|
|
|
|
Our sponsors make financial contributions toward the costs of publishing Linux Gazette. If you would like to become a sponsor of LG, e-mail us at .
TWDT 1 (text)
TWDT 2 (HTML)
are files containing the entire issue: one in text format, one in HTML. They are provided strictly as a way to save the contents as one file for later printing in the format of your choice; there is no guarantee of working links in the HTML version.
Got any great ideas for improvements! Send your
This page written and maintained by the Editor of Linux Gazette,
Write the Gazette at
|
Contents: |
Date: Tue, 06 Jan 1998 17:09:31 +1000
From: Peter Scott
Subject: Help - Adding third hard drive
I've been using Slackware Linux 2.0.29 for quite some time. I've managed with 2 drives with partitions for Win95 and Linux, but now I need to add another drive. It is recognised in the BIOS and can be found in Windoze, but I get no joy from Linux. I expected to be able to mount the drive straight away. Do I need to do some insnod or mke2fs or something.
The Mailbag!
# mount /dev/hdc1 /mnt
mount: the kernel does not recognize /dev/hdc1 as a block device
(may# fdisk /dev/hdc
# fdisk /dev/hdc
Unable to open /dev/hdc
I've got a fealing that I need to reconfigure Lilo or something? I know that I've forgotten something obvious, but I've wasted hours without any joy.
thanx,
pete
Date: Tue, 06 Jan 1998 19:55:08 +0000
From: George Russell
Subject: Installing StarOffice 3.1 on Redhat 4.2
I'm having difficulties installing StarOffice onto my system. I've installed the rpms for static binaries, common files, english demos and english docs. I've run the setup script and done a user install, after updating libc and ld.so, and would like to now run the package. It says to install two daemons, svdaemon and svportmap . These both need something called rpc and the portmap daemon, which I can find no reference to on my system. How can I install these so that StarOffice will run. All help gratefully recieved.
--
George Richard Russell
Date: Sat, 10 Jan 1998 05:55:26 -0600
From: ReXsOn RuLeZ
Subject: Question....
Hello there... sorry to bother with probably one of the stupidist questions in the world, but I want to install Linux on my computer; the problem is that I share a computer with my family and of course they don't have a clue of what I do so they don't care, they just want to be able to use office to do their work. I've looked around various Linux sites trying to find an answer but I've been unsuccesful. My question is this: As I told you I have a windows95 box and all the documents that
Are outthere focus on installing linux in a DOS environment which in my case and a lot of people it's history. I have a 3 gig hardrive that I think is partitioned already in 2 because I have a c: and d: I'm not sure if they're separate hardrives or one is partitioned. What I would like to know is what should I do here. I'm not sure if my second drive which is 1 gig is already formated for windows which I think it is because it has a recyble bin. I don't know what to do because I'm afraid that if I delete or erase the partition the whole thing will become one hardrive and I will have to erase everything to partition that one hardrive. I was kind of hoping there was a way or partitionin my second hardrive (d:) and leave a part for windows and another for Linux.
As I told you earlier I'm sorry to make this kind of questions but if I damage something of this computer my dad would prive me of even looking at it, and I don't want that to happen. I would really aprecciate your help since I'm really eagered to use Linux.
Thanx in advance for your help.
Rexson
Date: Sat, 17 Jan 1998 20:39:14 -0400
From: Frank Nazario
Subject: HI...
I've just finished browsing your Gazzettte and it is very cool...as a web administrator at http://www.prplaza.net I was fedup with the performance and slowness of an NT enviroment and decided kind of reluctant to migrate to Linux (right now i'm a green thumb at it)... But and a big BUT after seen a single processor pentium pro 200 server running linux redhat 5.0 and Apache Webserver blow the doors of a dual pentium pro 200 running on NT and IIS3.0...i was sold in the spot....never to touch Microsoft NT again ... and feeling good about it.
My problem is this one ... I've gone bananas in trying to find a document that explains how to install, in a step by step fashion, the Apache SSL "extensions" to one of my Apache WWW Webservers (the performance increase is awesome) can you or anyone that reads this help...
thanks beforehand for you response....
Frank Nazario San Juan, Puerto Rico
Date: Sun, 18 Jan 1998 11:36:50 -0500
From: Michael Vore
Subject: Problems with CD-ROM
Admittedly I'm not sure where the problem lies, When using NT-4/Netscape Communicator-4 to view the cdrom all links look like "file:///El/lj/" Which of course will not be found. I have looked at the source to try to find why the double '//' and the '/El' come from. Any ideas? (and any work arounds??)
At the moment I don't have X running on my Linux machine - it's a new install of RedHat and during the upgrade I forgot to same the XConfig files.
mike
Date: Mon, 19 Jan 1998 09:52:28 -0500 (EST)
From: Michael Stutz
Subject: Help Wanted: SVGALIB Screenshots?
Is there any way to make a screenshot of a graphical program that runs on the console (_not_ in X)?
Date: 21 Jan 98 11:28:04 -0500
From: Jonathan Smith
Subject: netcfg
I am using X to connect to my ISP via the netcfg command. I have it starting up at boot time. This works great, but I was wondering where the chat script and pppd command are hiding for the ppp interface that you can create via netcfg.
I was also wondering if there was a way to prevent my ISP from dropping me after a given time of activity. I am using a cron job to ping to my isp, but that does not seem to prevent this from happening. Should I try pinging to a server other than my ISP?
Thanks, Jonathan Smith.
Date: Thu, 22 Jan 1998 02:38:11 -0800 (PST)
From: Jaume Vicent
Subject: Sound Card MED3931
I'm a new Linux user (kernel 2.0.29). My sound card is a MED3931, with a chip OPTi 82c931.
As it is a PnP card, I use the isapnptools-1.9 package, loading the sound support as a module. I've tried configure it as a MAD16 or MSS (Microsoft Sound System) but it hasn't worked in any way.
I don't know if the problem is with the IRQ/DMA/IO settings (I use the same ones as with Windows 95) that I set in the /etc/isapnp.conf file, or it is that the sound driver (OSS/Free) just doesn't support this card.
Can you help? Thank you.
Date: Thu, 22 Jan 1998 22:51:09 +0200
From: Asaf Wiener
Subject: from were can i download (for free) LINUX?
I have an inter pentium, and I would like to install LINUX in my computer. But, I don't know from were can i download the installation files (for free), I heard that LINUX is a free softwere, but i don't find a site that i can download for free LINUX. Please help me to find such a site (and also some install instractions).
Thank you,
Asaf wiener
Look on the Linux Resources page to find pointers to everything you need, http://www.linuxresources.com/ --Editor
Date: Fri, 23 Jan 1998 14:59:00 +1100
From: Peter Lee
Subject: POP3d Problem
I am having problem connecting to the POP3 Server in Linux. This problem only arise when a new email arrives or there are mails in my mailbox If I delete all my mails I can connect to the POP3 Server. Error message I get is:
ERR - being read already /usr/spool/mail/
I have removed the account and recreated it again. Still problem occurs. And I know I am the only one logged on. The only way I can read my mails is manually telneting to the Linux and use either pine or mail from the unix command
Any Suggestions ?
PETER LEE
Date: Fri, 23 Jan 1998 13:02:25 -0003
From:
Subject: Printing postcript ...
I really want to print some using postscript form but I can't ... So, I have read a lot of docs and unfortunately when I try to print some I just got the postscript language.
I tried configure the 'printcap' and so on but. My printer is a CANON 4200 Bj and I am running Slackware 96 Linux Version.
Oh: I just gave a look at the RedHat 5.0 comments and seems it make easier. I am thinking about purchase it.
Thanks a lot. I would appreciate a reply.
Regards,
Rafael.
Date: Sat, 24 Jan 1998 08:09:51 -0500 (EST)
From: Casimer P. Zakrzewski
Subject: IBM 8514 monitor
Hi. I'm new to Linux, and my problem is installing my monitor, an IBM 8514, for use with X-Window. I use an S3 Virge 86C325 accelerator card.
After installing Red Hat 4.2, the monitor works fine for command line, but when I try using it for X-Window, the screen shrivels up to something less than a 3x5 recipe card! I've tried reconfiguring different combinations of color depths and screen resolutions, and have come up with everything from a blank screen to 'your worst nightmare'.
I'm stumped. I've tried the different FAQ sites, but can't find one that can give me a hint of how to configure this monitor for use with X-Window. I'd appreciate any help anyone can give me. I had to resort to installing Win95 and IE (which work for this monitor/card) just to send this out. Thanks in advance for any help I can get.
Zak
Date: Sun, 25 Jan 1998 11:06:17 -0800
From: Apple Annie
Subject: Re: Remote address on Chat sites
I am not a very literate person on the internet, so many of the vernaculars used are over my head. However, am having a problem of people "killing" me when they wish to , on Java Chat room. I would like to be able to eliminate my Remote number coming up with my user name . Is there a simple way of doing this? I do not desire these people to locate my server & other information. Thanks for your response, if you can give me help. If not, then thank you anyhow.
Sincerely yours,
Anne L
Date: 27 Jan 98 13:18:56
From: dennis.j.smith
Subject: Linux and VAX 3400 and 3300
I have just purchased a MicroVAX 3400 and 3300. I would like to put Linux on these two systems. Can you provide any help in this aspect.
Dennis
Date: Wed, 28 Jan 98 15:54:55 MST
From: Antony Ware
Subject: Linux and Children
I've been hunting around for linux software for toddlers. My eldest (3) has had fun with xpaint, and he likes to "type", but there's a lot more going on at his level on my DOS partition. (:-(
So far, my searches in the linux world have turned up...nothing. Does anyone know of anything out there?
Cheers,
Date: Mon, 5 Jan 1998 12:14:09 PST
From: Marty Leisner
Subject: I don't like long articles
Glen Fowler's article comparing NT and linux processes is too long for the gazette (IMHO) and didn't print out good from netscape...
HTML is not the best media for everything, maybe the gazette should have an abstract and a URL for a postscript or tex master.
marty
Date: Tue, 06 Jan 1998 11:07:06 +0100
From: Trond Eivind Glomsrød
Subject: Linux and routing
In the January issue, you ask for readers to write an article on how to connect a LAN via just 1 IP address...
That is rather unnecesarry - there is a mini-HOWTO on it, called "IP Masquerade mini-HOWTO". Available from your favorite LDP mirror.
Trond Eivind Glomsrød
Date: Tue, 13 Jan 1998 22:26:57 -0600
From: chris rennert
Subject: Rookie
Hello I am a newbie to Linux and I am very excited that I stumbled across the Linux Gazette.. I have been wanting to put up a home LAN with 2 pc's for some time ... and the article on SAMBA has put me on the right track. I am a computer science student here in Wisconsin and I love using linux. I will keep reading .. I just hope that you keep printing.. Thanks again and I hope I can contribute in the future to this great Mag.
Chris Rennert
Date: Sat, 17 Jan 1998 01:32:06 -0700
From: Sean Horan
Subject: Server uptime
I'm sending this maybe as news, perhaps Linux stability and advocacy.
I heard that the record for keeping up a Linux server up continuously without reboot is six months. Here's the output from executing 'w' on our Linux 1.2.8 system.
1:48am up 274 days, 17:05, 1 user, load average: 1.09, 1.02, 1.00 User tty from login@ idle JCPU PCPU what sean ttyp1 sss2-01.inre.as 1:46am w274 days, 24 hours a day. Never restarted. How common is this?
Let us know
--Sean
Date: Sun, 25 Jan 1998 15:04:35 -0800
From: Sean Russell
Subject: Linux security
I'm not intending to kick of a debate of the merits of PAM, but I have a couple of comments and a question.
The question is, has anybody, commercial or freeware, started coding an MVS-like security system for Linux? Specifically, I'm interested in the fine granularity of access controls, the ability to deal with more than just file accesses, user configurable ACLs, and most importantly, security at the kernel level. One thing I find most distasteful about PAM is the fact that applications have to be PAM aware to make use of PAM's abilities. MVS security, on the other hand, is soft-linked into the IO layer of the kernel, and /all/ applications use that security model without knowing anything about it.
Anyone who has any comments on this, information, or leads, please email me.
Thanks!
--- SER
![[ TABLE OF CONTENTS ]](../gx/indexnew.gif)
![[ FRONT PAGE ]](../gx/homenew.gif)
More 2¢ Tips!
Linux - 2 Cents about vim for pico usersDate: Mon, 5 Jan 1998 23:07:20 +0100
From: Sven Guckes
I just read the "2 cent tips" again and I thought you might enjoy this tip:
Several people enjoy the editor "pico" but do not feel comfortable with an editor like "vim" for several reasons - one of these being that it is so easy to do reformat the current paragraph with ^J (control-j) within pico while it is so "difficult" within Vim. Well, all it takes is two mappings for Vim:
nmap <C-J> vipgq
nmap <C-J> gq
Put these mappings into your setup file (on Unix and esp Linux this is ~/.vimrc) and you can use ^J to reformat the current paragraph or the currently highlighted text (use 'V' and some movement commands to do that, for example).
More tips can be obtained from these Pages:
http://www.vim.org/ Vim Home Page
http://www.vim.org/faq/ Vim FAQ
http://www.vim.org/answ.html Vim Answers Page
(for everything not yet in the VIM FAQ)
http://www.vim.org/rc Sven's Huge Setup File with comments
And for those people who use "some vi" but never got the hang of it - here is a page about "why" you would want to use a vi clone such as Vim:
http://www.vim.org/why.html
Enjoy!
Sven
My 1/50th of a DollarDate: Wed, 07 Jan 1998 01:27:09 +0000
From: Michael Katz-Hyman
Here is a small shell script I wrote to blink the scroll lock on my keyboard when new mail arrived.
--------------------------------------------------------------
#!/bin/bash
#
# Keyboard blinky thingy when you have new mail, sleeps 5 minutes if you
don't
#
# Michael Katz-Hyman ([email protected]) running Linux 2.0.33 Red Hat
4.0
Mail_File = "/var/spool/mail/mkatshym"
# The static file is used to make the script a daemon (I just test to
see if /bin/bash is present :- )
Static_File="/bin/bash"
LED_SET_COMMAND_ON = "/usr/bin/setleds +scroll"
LED_SET_COMMAND_OFF = "/usr/bin/setleds -scroll"
Sleep_Command = "/bin/sleep 2m"
# O.k. lets get started
while [ -e $Static_File ]; do
while [ -s $Mail_File ]; do
$LED_SET_COMMAND_ON
$LED_SET_COMMAND_OFF
done
if [ ! -sMail_FIle ]; then
/bin/sleep 5m
fi
done
------------------------------------------------------------------
Michael Katz-Hyman
sound problemsDate: Wed, 7 Jan 1998 09:48:10 -0600 (CST)
From: Mike Hammel
> Have installed RedHat 5.0 and configured the sound card using sndconfig. > All went well and I heard the demo sound bite of Linus. However, I > have never heard another sound since. When browsing web sites with sound, > no audio is played. Anyone have any ideas?First, cat an audio file to the audio device: cat file > /dev/audio. If you get sound out then the device is fine. The problem is probably that you haven't configured your browser to play the audio. With Netscape you would use the Preferences->Navigator->Applications option. You'll need to configure the various audio types to be played using whatever tool you choose (I don't play much audio, so don't have anything configured in my browser to do so). The cat command will work with .au files, and maybe .wav (I think), but possibly not with others. You might want to look at the Linux Application and Utilities Page or the Linux Midi and Sound Page for hints on getting applications for playing sound files. Both of these have links on the Software Resources page at the Linux Journal: http://www.linuxresources.com/apps.html.
Hope this helps a little.
Michael J. Hammel
Filtering output of binary filesDate: Wed, 7 Jan 1998 14:56:05 -0500
From: Sylvain Falardeau
When you do a cat/grep/etc. of binary files on a tty, the terminal may become unusable because of some control character.
Guido Socher ([email protected]) suggests a
sed -e 's/[^ -~][^ -~]*/ /g'
to filter unprintable characters. You can simply use a
cat -v
and all the control characters are escaped to be printable. It's very useful when you are "cating" files and don't know if they contains control characters.
Easter Eggs in NetscapeDate: Thu, 8 Jan 1998 11:53:51 +0000 (GMT)
From: Caolan McNamara
* From: Ivan Griffin [email protected] * * These special URLs do interesting things in Netscape Navigator and Communicator. * * about:cache gives details on your cache * about:global gives details about global history * about:memory-cache * about:image-cache * about:document * about:hype * about:plugins * about:editfilenew * * view-source:URL opens source window of the URL * * Ctrl-Alt-F take you to an interesting site :-)At least some of the netscape developers have an about for themselves, e.g about:kahern.
C.
RE: Perl and HTMLDate: Thu, 08 Jan 1998 16:58:44 +0000
From: Carl Mark Windsor
In reply to Gabriele Giansante ([email protected]), whose return mail address does not seem to work.
--------------------------------------------------------------
Gabriele,
The #!/usr/local/bin/perl line is what is used to indicate that this is a perl script, but netscape is not clever enough to know this, it has to be told.
Go to Options / General Preferences / Helpers and edit (if it exists) or create (if it doesn't) the following configuration
Description: Perl Script Type: application/perl Suffix: plTick the Application box and put the path
Application: /usr/sbin/perl <-----(or the path to your perl)Sorry if you have heard this all before!
Carl
Update locateDate: Sat, 10 Jan 1998 19:16:31 +0000
From: Joaquim Baptista
Both Redhat and Slackware (not sure about Debian) install the package updatedb. This package has two programs:
- "updatedb" scans the filesystem and generates a database of existing files. This is run every night as root. - "locate" is run by users to quickly locate files on the filesystem, using the database generated by updatedb.My problem is that "updatedb" runs at 4:40 in the morning, and my machine is rarely running at 4:40. Thus the database is never updated and "locate" never finds any recent file.
The solution is not very simple: updating the database hits the disk hard and takes some time; it is hardly a task to be performed every hour.
My solution is to run a script every hour that updates the database only if it is more than 24 hours old. I (ab)used find to do the task.
Here is the script "run-updatedb":
#!/bin/sh
/usr/bin/find /var/spool/locate/locatedb -mtime +1 -exec \
/usr/bin/updatedb \
--prunepaths='/tmp /usr/tmp /var/tmp /mnt /cdrom /floppy /var/spool' \;
I also had to change the crontab for root: I commented the old line that runs updatedb at 4:40, and added a line that runs my script every hour:
0 * * * * /usr/local/sbin/run-updatedb 1> /dev/null 2> /dev/nullOne final note: I believe that both Redhat and Debian have "super-crontabs." That means that you must fish around in /etc (/etc/cron?) for extra crontab files (long live Slackware!).
Best regards,
Joaquim Baptista, alias pxQuim
Doing spaces in file namesDate: Tue, 13 Jan 1998 18:16:48 -0800 (PST)
From: Mark Lundeberg
If you think Win95/NT filenames are better than Linux ones, think again. In bash, (this may work in csh, but I never use it) use quotes to enclose the filename in the parameters of a program:
echo "test" > "spaced name"
and do an ls, and you see a space in the middle of the filename! This can be used for confusing people, by going:
echo "Hi" > "test "
(notice the space at the end of "test ").
Then, someone tries to open the file "test" as it looks from ls, but all it does is open a new file.
PS: The ext2 filesystem allows names of up to 255 chars long, just like Loseows 95.
Go Linux!
Mailing binary files to Microsoft clientsDate: Fri, 16 Jan 1998 12:37:22 +0000 (GMT)
From: Ivan Griffin
Quite often I receive a mail with an attachment in that weird Microsoft format which is not quite MIME. It's easy for a Unix client to decode such attachments -- save the message as a file, and run uudecode or the excellent freeware uudeview on it.
However, sending a mail message to such a Microsoft mail user is a little different -- you cannot send them a standard MIME message (unless they are using Exchange I believe). I have found the following script useful in such situations.
Say, for example, I wanted to send a file foo.gif to user mike. I would run my script as follows:
msmail_encode foo.gif > mail_message
Then I would read the mail message into the body of the message I wanted to send. This script could easily be improved to include automatic mailing, and editing of the mail message proper.
#!/bin/sh echo "[[ $1 : 2628 in $1 ]]" echo "" echo " Microsoft document attached. " echo "" echo " Regards, " echo " Ivan." echo "" echo "The following binary file has been uuencoded to ensure successful" echo "transmission. Use UUDECODE to extract." echo cat $1 | uuencode $1
By the way, I have no idea what the 2628 above refers to. It is a number generated somehow by Microsoft mail clients, but they don't seem to need it, so the 2628 is a value I received once in a mail message.
Regards,
Ivan.
Linux and RoutingDate: Sat, 17 Jan 1998 11:02:43 -0800
From: James C. Carr
I am not sure if you have already received a reply regarding your question on routing a LAN to the 'net, so I thought I'd go ahead and give it a shot. The CC to Linux Gazette is just in case no one else has sent in a more elaborate reply. ;) Also, this is something that was mentioned back in Linux Journal number 43 ( November 1997 ), so most of this stems from that particular article, "IP Masquerading Code Follow-UP". To avoid re-hashing someone else's wonderful article, I'll just skim over what I use here at my own home.
======================================================================
Linux and Routing with ipfwadm
======================================================================
Getting Linux to route information between a LAN and the 'net will require you to re-compile the kernel with IP Masquerading support. Of course, one could also use firewalls and disable the routing, but I don't have experience with that just yet. If your kernel version is < 2.0.30, you'll need to enable the "Code Maturity Level" option at re-compilation -- this gives you access to the other Network Options in the kernel, such as IP Masquerading support.
After installing the new kernel, obtain and install the ipfwadm program; this usually comes installed on a base Debian 1.3.1 system, and is easily obtainable for Red Hat. Executing ipfwadm from my end includes the following commands:
/sbin/ipfwadm -F -p deny
This portion breaks down as follows:
-F -- Notify ipfwadm that you're modifying the IP forwarding rules.
-p -- Tell ipfwadm that you want to deny the forwarding of incoming packets.
I've experienced certain web pages that will not open with this option set; it's probably some Microsoftian plot, you know. ;)
/sbin/ipfwadm -F -a m -S 192.168.0.0/24 -D 0.0.0.0/0
-F is the same as above.
/sbin/ipfwadm -F -l -n
Let's make sure this thing is up and running.
-l -- List all IP # forwarding rules;
-n -- convert the information to numeric format.
Of course, you'll need to have assigned your computers with IP addresses within the 192.168.0.* range to use the exact commands above. On my own setup, the primary computer gets 192.168.0.1, and the others fall in succession. Be sure to have all the computers that are being masqueraded set their gateway address to the primary, e.g. secondary.my.com (192.168.0.2) uses primary.my.com (192.168.0.1) as its gateway to the 'net.
For a far more in-depth article regarding this type of set-up, I do suggest reading Chris Kostick's article "IP Masquerading Code Follow-up" in the November 1997 issue of Linux Journal. Not only does it cover the basics, but the author also explains a few more subtle aspects to ipfwadm. Besides, without the help of this article, I wouldn't even know the small amount about ipfwadm that I do. :)
======================================================================
I hope this helped at least a little,
-- James
Linux and Routing 2Date: Tue, 6 Jan 1998 13:25:57 -0500 (EST)
From: Paul Lussier,
> I plan on getting a cable modem soon, so the bandwidth would be pretty
> high, so that is why I have decided to try to make this connection
> provide for my whole house via a LAN connection in my home. What I
> have read is that you could use the private IPs, meaning the 10.x.x.x
> or so, 192.168.x.x and some others for the IP of the LAN and have
> these connect to some box (the LINUX box?) that would provide its
> connection to the internet to the inside LAN connected to the box. Is
> the problem that you would have to route the assigned address to the
> private IPs for the LAN use. I have also read that this would slow
> down the connection a bit or something, but that is a price I am
> willing to pay. So, the summary of the question is how would I be able
> to connect many computers to the internet via just 1 assigned IP
> address? I would like to be able to do it using my LINUX box connected
> to the internet via cable modem, and to my LAN via an Ethernet
> link. Any help is much appreciated, thanks.
This caught my attention, especially since I'm the Unix admin for Baynetworks Broadband Technology Division (formerly LANcity) and we pretty much invented this technology, along with being the leader in the Cable modem industry :) Now that I've got the plug in for company I'll get down to your problem :)
I first must admit that 1.) I don't own a cable modem (I can't get cable, long story :( and 2.) I don't do any routing of this nature. But I have read a lot about it, and I do work with cable modems, so I think I can help a little :)
The first thing to understand is that with Linux, you don't want to be routing, and definitely do not want to run routed to do what you want to accomplish. Rather, you want to be doing IP forwarding/IP masquerading which you would enable in the kernel by re-configuring/re-compiling a new kernel. You'll definitely want to scour the HOWTOs, I believe there is one on this subject. In addition, you may want to check out the Linux Network and/or Systems Administrator's guides, as they too, probably have some good infomation in them. Other good references may be:
Some words of caution. DO NOT HAVE YOUR LAN CONNECTED AT THE TIME OF THE CABLE MODEM INSTALLATION!!!! MediaOne, Cablevision, Time Warner, and most of the other cable companies (we deal with them all here) will refuse to connect a LAN to their broadband network. Simply remove your hub or coax cable from view, and let them do what they need to do, then connect everything else up after they leave. =20
You will need 2 Ethernet NICs in the system which will be connected to the broadband, one for the cable modem and one for the internal LAN.. Most cable companies will gladly provide and install one for you (MediaOne charges $120 for a 3C509 + labor). I recommend telling them you have a NIC, and going out and buying one and installing it yourself.
The cable modem, in reality, is NOT a modem. It's an Ethernet Bridge. When the modem^H^H^H^H^Hbridge boots/powers up it does a bootp request to a server at the cable companies central office to obtain an IP address. The NIC is also assigned an IP address, which (at least with MediaOne) is registered to the MAC address on the NIC (MediaOne doesn't want you to move the modem to another computer after they leave. They apparently check the modems from time to time to see what MAC they're connected to). Therefore, you want your proxy server/firewall configured so that it prevents all incoming connections from the cable modem and allows only outgoing connections. You want the IP forwarding/masquerading set up to allow other systems on your private lan to use the proxy server as a proxy server (I'm not sure if using the term gateway here is correct).
Some other interesting tidbits of information about cable modems and cable companies:
Seeya, Paul
Netscape's AboutsDate: Tue, 20 Jan 1998 16:00:46 +0100
From: "Stefan K."
I've read the article about the about's of Netscape... Here's some more (some of them may not work or simply do nothing)
about:montulli
about:nihongo
about:francais
about:plugins
about:document
about:license
about:cache
about:global
about:image-cache
about:memory-cache
about:security
about:hype
about:blank
about:mozilla
about:security?subject-logo=
about:security?
about:security?banner-mixed
about:security?banner-insecure
about:security?banner-secure
about:security?banner-payment
mocha:
javascript:
livescript:
view-source:
about:FeCoNtExT=123
PEACE!
kampi
Netscape on the DesktopDate: Sat, 24 Jan 1998 06:46:22 -0500
From: Tim Hawes
I do a lot of my web development work at home on my Linux box. Netscape for Linux does not automatically check for an existing Netscape session. As a result, if you try to run two different Netscape sessions, you will get an error message box with something like the following:
Netscape has detected a /home/thawes/.netscape/lock
file.
This may indecate that another user is running
Netscape using your /home/thawes/.netscape files.
It appears to be running on host localhost under process-ID 316.
You may continue to use Netscape, but you will
be unable to use the disk cache, global history,
or your personal ceritificates.
Blah, blah, blah.
If you are like me, and like to have links to URL's using Netscape on your menus, FVWM GoodStuff or desktop icons, this can be a real nuisance, having to completely start a new Netscape session each time. Or you can have them link with this:
netscape -remote 'openURL(your.url)
But then none of your links will work if Netscape is not currently running. This shell script will look for the lock file that Netscape creates when it is started. If it does not find the lock file, it will start a fresh Netscape session. If it does find it, it will send a netscape -remote command to your current session with the URL you provide in the argument. If you do not provide a URL, netscape will simply give you a popup message indicating that you did not specify a URL. If you do not want Netscape to start up a new window for the URL, just get rid of the "new-window" in the argument in the shell script.
#!/bin/sh
if [ -L $HOME/.netscape/lock ]
then exec /usr/local/netscape/netscape -remote
'openURL('$*',new-window)';
else exec /usr/local/netscape/netscape $*;
fi
exit 0
There are limitations with this script. First of all, if Netscape did not exit cleanly after the last session, then the lock file will still be present in your ~/.netscape directory. The script will then try to execute a netscape -remote command and will error out with the console message that Netscape is not running on :0.0. If you are not redirecting your console messages anywhere, then you will not see anything except Netscape not-starting.
1. Do a ps to see if there are any zombie processes left over from your last netscape session.
2. Kill all zombie processes
3. $ rm ~/.netscape/lock
4. retry
I am sure there is a way to automate this through a shell script as well, but I have not yet any time nor motivation to write it. Some other shortcomings include trying to start Netscape composer with the -remote argument for a currently running netscape session. But then this is probably why you should never name a shell script after the actual binary it attempts to start.
All in all, if you envy the functionality of Netscape on Windows 95, automatically checking for an existing netscape session to send the browser surfing, and starting a new session if it does not find it, well, here is a simple solution for Linux users, using the power of the shell.
Tim Hawes
Re: Printing ProblemsDate: Sat, 31 Jan 1998 20:09:18 +0100 (MET)
From: Roland Smith,
>Anyone that can help me. I'd love to hear it. I try running
>lpr, but everytime I get no name for local machine.
>How do I set this and/or what is the problem.
>Manish Oberoi
It sounds like you're using LPRng. This is a new version of lpr that's more suitable for networks. It is included in the newer Slackware releases and maybe others.
My solution was to grab the bsdlpr.tgz package from ftp.cdrom.com and use that (This is meant for Slackware). Otherwise you can search the Net for "bsdlpr".
-- Roland
Re: Using a 386 ComputerDate: Sat, 31 Jan 1998 20:13:09 +0100 (MET)
From: Roland Smith,
>I used to have a 386 25 MHz computer. Not long time ago I bought a
>Pentium 200 MHz computer. Since then I have not played with 386.
>Is there any easy and economical way to connect the 386 to the
>Pentinum computer where I will install the Release 5.0. If so,
>what I can do with it or at lease what I can learn from it.
If you connect both machines with a parallel cable, and configure PLIP into the kernel on both machines, you can have your own little network. A 386 should at least work nice as a terminal, even if it might not run X :-)
-- Roland
 |
Contents: |
March Linux JournalThe March issue of Linux Journal will be hitting the newsstands this week. The focus of this issue is Graphical User Interfaces with articles on XView, GTK+, X-Designer and CDE. Check out the Table of Contents.
Netscape Announces Plans To Make Source Code FreeNetscape Communications Corporation today announced bold plans to make the source code for the next generation of its highly popular Netscape Communicator client software available for free licensing on the Internet. The company plans to post the source code beginning with the first Netscape Communicator 5.0 developer release, expected by the end of the first quarter of 1998.
Netscape is releasing its currently available Netscape Navigator and Communicator Standard Edition 4.0 software products immediately free for all users.
In addition, the company separately announced the launch of an aggressive new software distribution program called "Unlimited Distribution" to broadly distribute its market-leading Internet client software for free. Unlimited Distribution enables Original Equipment Manufacturers (OEMs), Internet Service Providers (ISPs), telecommunications companies, Web content providers, publishers and software developers to download and redistribute Netscape Communicator and Netscape Navigator easily with "no strings attached."
To read and post reactions about this latest announcement, Linux Journal has added a discussion group to our pages.
Linux in the NewsEric Raymond's article "The Cathedral and the Bazaar" evidently made the rounds at Netscape and helped convince them that giving away Navigator source code was a good idea. If you've never read it, now is a good time.
Check out the article by Barton Crockett on msnbc: A Titanic Challenge to Microsoft
The February issue of Dr. Dobb's Journal has an interview with Larry Wall, the creator of Perl.
The SEUL ProjectFor more information:
Roger Dingledine,
http://www.seul.org/
The Linux Clothing ProjectCheck out http://genocide.adept.co.za/lcp/ to have your questions answered.
We're planning another t-shirt, with ordering opening on the 1st of February, 1998. All the info is on the page.
For more information:
Albert Strasheim, UUNET Internet Africa,
Stampede Linux Logo Contest!Along with the highly anticipated release of Stampede Linux 0.55 (heber), the developers felt it time to have an official logo. The developers also felt that they should look elsewhere for development of said logo. This contest is a result of the looking elsewhere bit. (Yes, prizes are part of this contest =]).
For more Information:
Matt Wood, Stampede Linux Head Developer,
http://www.stampede.org/
12th SYSTEMS ADMINISTRATION CONFERENCE (LISA '98)December 6-11, 1998
Boston, Massachusetts
The LISA '98 program is put together by a volunteer committee of experienced systems administrators. The Program Committee welcomes your submission. The Call for Participation is now available at http://www.usenix.org/events/lisa98/
Sponsored by USENIX, The Advanced Computing Systems Association Co-Sponsored by SAGE, the System Administrators Guild
Japanese Word ProcessorPerhaps you'd like to work on another exciting project? There is a Windows application, called JWP -- a Japanese Word Processor. This package was written by Stephen Chung, and as a GNU product it is freely distributable. I've used it extensively over the past few years, and it is a *great* package.
Unfortunately, JWP is only available for Windows right now, which is locking out a lot of people under other platforms who might benefit from it. As Stephen is quite busy with full-time work and maintaining the Windows versions (he's developing version 2.00 now), Steve Frampton has decided to go ahead with a port to X-Windows.
The JWP-Port Project home page contains more information on the JWP package as well as the JWP-Port project itself. If you are interested, please visit the page at http://qlink.queensu.ca/~3srf/jwp-port/.
For more information:
Steve Frampton,
A 3D CAD Application for Linux ProjectFreeDesigner is intended to be a fully extendable Computer Aided Design and Drafting (CAD) application for Linux and other Unix type operating systems. Initially K Desktop Environment and GNOME/GTK frontends will be investigated, although it will be written as "toolkit inspecific" as is possible, by utilizing a GUI abstraction layer in FreeDesigner Core.
For more information:
Fleming, Petersen & Associates, http://www.fpa-engineers.com/OD/
Artificial IntelligenceInterested in Artificial Intelligence, Eveolutionary Computing, Connectionism, Artificial Life, and/or Software Agents? Want to find out what software is available for Linux in these areas? Or are you just curious?
If so, check out my Linux AI/Alife mini-HOWTO at: http://www.ai.uga.edu/~jae/ai.html
For more information:
John A. Eikenberry,
Digital Domain and Red Hat LinuxDigital Domain used Red Hat Linux not only for special effects in the movie Titanic but also in commercials that debuted during this Superbowl. Here's Red Hat's press release.
eVote 2.2Date: Wed, 28 Jan 1998
eVote image
eVote is a freely available add-on to email list-servers that gives the members of the list the ability to poll each other. After installation of the software, the administrator is not involved. All participants have the power to open polls, vote, change their votes and view each other's votes if the particular poll was so configured. The underlying specialized data-server, The Clerk, is also freely available for Linux systems only. eVote 2.2 is available in both English and French.
For more information:
Marilyn Davis, , http://www.Deliberate.com/
FunktrackerGOLD 1.1FunktrackerGOLD 1.1 has been released. FunktrackerGOLD is a module editor for Linux that allows you to compose digital music (similar to Fasttracker, Impulsetracker etc for those who are familar with them).
For more information:
Jason Nunn,
http://www.downunder.net.au/~jsno/proj/unix_projects/
QuikscriptQuikscript is a PostScript text formatting and typesetting program. It enables documents to be prepared on any type of hardware, using visible layout marks to control the appearance of the output, and produce output on a PostScript printer by despatching Qs and the document file to the device. No processing is performed by the host hardware; all processing is done within the printer.
The advantage that Quikscript provides, other than portability, is precision of control over output. Because it is written in PostScript, it is interpreted at run-time within the printer. It is possible to create documents that modify the Quikscript program during execution. It is very easy to include other PostScript programs or fragments with Quikscript. It is possible to use special PostScript fonts, such as hand-generated ones. Graphics generated from a variety of sources can be easily included, as can text output from computer programs. It is possible to embed Quikscript within a document, such as an advertisement or a telephone bill.
The Quikscript distribution is available by anonymous ftp from "ftp.adfa.oz.au" in the directory "pub/postscript". It may also be accessed through the World Wide Web at URL http://www.cs.adfa.oz.au/~gfreeman/
For more information:
Graham Freeman,
YP-Tools & YP-ServerVersion 1.4 of the YP (NIS version 2) tools for Linux has been released. This package contains ypcat, ypmatch, ypset, ypwhich and yppasswd. You need this package for GNU C Library 2.x and Linux libc 5.4.21, but you should use libc 5.4.36 or later due some NIS bugs in libc. It replaces the old yp-clients 2.2 on this systems.
You could get the latest version from: http://www-vt.uni-paderborn.de/~kukuk/linux/nis.html
Version 1.2.7 of an YP (NIS version 2) Server for Linux has been released. It also runs under SunOS 4.1.x, Solaris 2.4 - 2.6, AIX, HP-UX, IRIX, Ultrix and OSF1 (alpha).
The programs are needed to turn your workstation in a NIS server. It contains ypserv, ypxfr, rpc.ypxfrd, rpc.yppasswdd, yppush, ypinit, revnetgroup, makedbm and /var/yp/Makefile. This is NOT an NIS+ (NIS version 3) Server ! ypserv 1.2.7 is available under the GNU General Public License.
You could get the latest version from: http://www-vt.uni-paderborn.de/~kukuk/linux/nis.html
For more information:
Thorsten Kukuk,
Motif 2.1 for LinuxThe latest and best release of Motif (version 2.1) is now available for the best operating system! Linked against both glibc (yes, it DOES work with RedHat 5) and libc (ie it works with Debian, Caldera, RedHat 4.0).
For more information:
LSL, http://www.lsl.com/,
NC Laboratories, http://www.nc-labs.com,
NetTrackerNetTracker is one of the most powerful, yet easy to use Internet and Intranet usage tracking programs on the market today. NetTracker allows marketing professionals, webmasters and ISPs to get the essential information they need to make informed decisions regarding their web sites.
A demonstration of NetTracker can be seen at [http://www.sane.com/demo/], and a free 30 day evaluation copy can be downloaded from [http://www.sane.com/eval/].
For more information:
Sane Solutions,
SCEPTRE-90SCEPTRE-90 a program for the analysis and simulation of electrical nonlinear networks and dynamic systems is now available for Linux users (free of charge). The ftp site, where the program can be found is: novilux.fh-friedberg.de/pub/sceptre_linux.
Detailed documentation in english and german as well as many samples are included in the archive file.
For more information:
Prof. Dr. Wolf-Rainer Novender,
BANAL 0.04 (free bookkeeping software)BANAL is a bookkeeping system that allows you to track invoices, clients, projects, TODOs, bank accounts and expenses. BANAL is a client/server application so you can keep one set of books on your system while allowing everyone access.
For this release, BANAL can store your information, list (and allow searching of) information and generate invoices, income and expense statements. You can also make and use recurring and memorized transactions to ease the burden of creating them manually. Check the TODO file, that is included with the distribution, for an idea of what is coming in the next release.
If you want to obtain BANAL and try it out, ftp to: ftp://sunsite.unc.edu/pub/Linux/apps/financial/accounting.
For more information:
Matthew Rice,
Aegis 3.1 - Software Configuration Management SystemAegis is a transaction-based software configuration management system. It provides a framework within which a team of developers may work on many changes to a program independently, and Aegis coordinates integrating these changes back into the master source of the program, with as little disruption as possible.
http://www.canb.auug.org.au/~millerp/aegis.html
For more information:
Peter Miller,
Free CORBA 2 ORB - omniORB 2.4.0The Olivetti and Oracle Research Laboratory has made available the second public release of omniORB (version 2.4.0). We also refer to this version as omniORB2. omniORB2 is copyright Olivetti & Oracle Research Laboratory. It is free software. The programs in omniORB2 are distributed under the GNU General Public Licence as published by the Free Software Foundation. The libraries in omniORB2 are distributed under the GNU Library General Public Licence.
Source code and binary distributions are available from our Web pages: http://www.orl.co.uk/omniORB/omniORB.html
For more information:
Dr. Sai-Lai Lo,
http://www.orl.co.uk/omniORB/omniORB_240/
New Linux STREAMS ReleaseLinux STREAMS (LiS) version 1.12 is now available. This version supports kernels 2.0.24 through 2.0.33. By mutual consent of the authors, the licensing terms have been changed to the GNU Public Library License. This allows linking of proprietary STREAMS drivers with the LiS code. This version contains an install script which automates the installation.
It can be downloaded from ftp.gcom.com from the directory /pub/linux/src/streams-1-15-98.
For more information:
Mikel L. Matthews,
Speech Enhancement by Kalman Filtering PackageIf you are interested in speech enhancement, signal processing in general, or applications of Kalman filtering, read on. Mr. Kybic has just finished his diploma work, entitled "Kalman Filtering and Speech Enhancement" which includes, among other things, an implementation of a Kalman smoothing based speech enhancement algorithm, working on speech signal corrupted by slowly changing coloured additive noise. Tested on Linux and HP-UX. Parallel version using PVM. It is not perfect but might be inspiring anyway. Free for non-commercial use.
http://cmp.felk.cvut.cz/~kybic/dipl
For more information:
Jan Kybic,
The Answer Guy 
Removing LILO, Reinstalling MS-DOSFrom: Stephen Britton,
My parents just told me that I have to give our extra machine (a 486 running Red Hat 4.1) to my younger brother, who only knows Windows. I have formated the drive with MS-DOS, but I can't seem to figure out how to remove LILO. I recall reading somewhere that it can be done by c:\fdisk /mbr But that doesn't seem to be working. Please help, he is returning to College next week!!
That should do it. However -- which version of MS-DOS are we talking about. This option was introduced in MS-DOS 5.0. Although it wasn't documented at the time it is widely used to recover from a variety of boot viruses.
If that that doesn't work -- boot from a Linux floppy -- zero out the whole partition table and MBR (dd if=/dev/zero of=/dev/hda -- for a primary IDE, or of=/dev/sda for the primary SCSI and count=1 (or 2 or so)).
Then you can boot from a DOS installation floppy and it will insist that you run fdisk and will treat the drive as though it was brand new and previously unformatted/partitioned.
(Technically you only have to zero out or put anyting other that 0x55AA as the last two bytes of the MBR -- that's the signature that tells FDISK that this drive has been previously partitioned. However, it's just easier to zero out the whole mess.)
Naturally this will make all of the data on the drive inaccessible -- but I suspect you already knew that was going to happen anyway.
Alternatively -- if fdisk /mbr doesn't work -- you should find out *why*. If this is an early version of DOS -- you should probably try to get a copy of 5.0 or later (or consider Caldera's OpenDOS). I suppose you could also consider installing Win '95, considering the likelihood that your brother will need access to TCP/IP utilities like web browsers and some e-mail package.
On the one hand I hate to push some further down the throat of the snake -- on the other hand we should always do our best to act in the best interests of our customers -- even when they're our pesky brothers.
P.S. I tried talking him into taking Linux, but he's locked into the Windows mindset.
Trying to convince someone of something is usually a losing proposition. Try to understand his real requirements -- and offer the best advice you can.
It may be that Windows is the best environment for him. It may also be that there are over-riding constraints that force him to choose a Windows compatible platform.
I think that many organizations are now "chained" to the Microsoft aggenda by their current investment in their existing data files (all their spreadsheets, documents, and many of their small, departmental mailing lists, and databases are locked into various versions of the proprietary .DOC, .XLS, and other data formats).
Microsoft clearly intends to maintain this state. I guess that is has been the core of their strategy for the last five years (since about the release of Win 3.0 or 3.1).
(It is also not unique to them -- most major commercial hardware and software vendors have tried to "lock" their customer into upgrade paths. Companies like DEC, IBM, and HP have each had their VMS, MVS, MPE OS' with this aggenda. Consequently their efforts at Unix have often been "skunkworks" -- and have been highly politicized for over a quarter of a century).
I ask people to consider this tidbit in their long range planning. Truly optimizing for the present requires looking to the future as well.
-- Jim
Running as root on Standalone Systems -- DON'TFrom:
What advantages are there, if any, to running your single-user system as a normal user and not root?
If you're absolutely perfect, you never make a typing mistake or issue a wrong command, or a right command from a wrong directory with the wrong arguments, *and* you only run perfect software, with no bugs in it at all, *and* you are totally disconnected from the world (you don't get any e-mail, never use netnews, or IRC etc) -- then you *might* be sort of safe running as root on your system.
If you simply don't care about your data and you like the idea of rebuilding your system configuration from scratch then throw all caution to the wind and go for it.
However, for the vast majority of us, it's the most minimal bow to prudence to log in as an unprivileged user for the vast majority of work you do at your system.
The advantages are:
By maintaining the discipline of only doing administrative tasks from a 'root' login -- and all of your other work from one or more 'user' accounts you are forced to pause and consider the implications of what you're doing.
It's also nice that you can partition your work into distinct domains -- you can always play games from your 'player' account -- and none of those games can damage you're thesis project, or financial records, or whatever.
Personally I think this could use some improvement. I'd like to see a system whereby by each user is implicitly the manager of a group of "roles." For single-user home systems this would be basically the same as using your root account to create new psuedo users for yourself. On multi-user systems it would delegate the task of creating new roles and rolegroups to the user --- so that each user's "base account" in effect becomes an administrator of this own roles.
The problem I see with that is that there's no support in Unix for it. I think it would take alot of work to build a set of tools to support it (and many of these tools would have to be SUID 'root' in traditional Unix systems -- or would require some totally different lower level support such as a variant of a "capabilities" system. In any event these tools would be very security sensitive -- and early versions would probably be the cause of numerous exploits.
However, none of that matters to the home user with root access to his own box.
-- Jim
More on Netscape Mail CrashesFrom: Chris,
In http://www.linuxgazette.com/issue24/lg_answer24.html, you suggest removing the ~/.netscape tree to stop Netscape Mail from crashing. I have had the same problem several times, and it does not appear to be anything in that directory -- it is the mail files themselves. It appears as though Netscape will occasionally put a wee bit of corruption in your ~/nsmail/[Inbox, Trash, etc.] files, which prevents it from reading them. And it crashes when it encounters any corruption in these files. It also seems to crash if your trash gets too large. (Anything over 1MB seems hopeless).
So one solution is to back up your mail elsewhere, and erase your mail directory. Then Netscape will create new, valid, empty mail folders, and stop crashing for a while. Another solution is to open the files yourself (they are just text files), and erase any messages that look suspect.
These sound like excellent troubleshooting suggestions, recovery procedures and workarounds.
I believe I also mentioned that my e-mail is far too important to me to entrust to Netscape (or any "new" product). For years I used 'elm' and before that it was 'mush' (mail user's shell). The switch from 'elm' to MH (using emacs' mh-e and Gnus interfaces) was nerve-wracking. (I deal with over a hundred messages a day -- and it's at the core of my business that I "keep up" on administration and security issues for my customers).
My biggest customer (another consultant in a different specialty) has also made this switch, after over a decade of using emacs' RMAIL. As you can imagine there have to be some pretty extensive advantages to a package to warrant changing from one client to another. (Merely having a "prettier" interface and a few bells and whistles isn't nearly enough).
Consequently I will probably stay in a poor position to answer questions about NS's mail and news readers.
As for the fact that NS crashes when encountering corruptions in folders and messages -- that's just poor quality control and poor coding. As usual the issues of "time-to-market" and "pretty interface" dominate the development of commercial products.
The nature of the computer software industry practically guarantees that the most widely used commercial products will have bugs of this sort. This is the result of a set of corporate priorities that don't match typical customer priorities -- and is a byproduct of the selection process by most software is purchased.
I could go on about this for many pages. Since I worked in the software industry for a long time -- I had a lot of time to observe the process first hand. (Since I was doing tech support I also had an abundance of free neural cycles to think about the issues, as well). Here's a few observations that will help explain my conclusion:
Sadly it takes *really* bad software to fail as a result of its bugs. dBase IV comes to mind. It doesn't take much for really high quality software to fail as a result of poor marketing (or the superior marketing and industry dominance of competitors). DESQview comes to mind.
By contrast almost all free software is chosen by end-users based on recommendations from other end-users. It is produced by people whose only rewards are: access to their own tool to solve their own problems, the satisfaction of having lots of users, and some chance for fame and sincere admiration. They gain nothing by claiming more than they deliver (except more e-mail with more support questions).
Luckily we, Linux and free software users, are blessed with alternatives. These systemic problems are what I think we are really "free" of.
-- Jim
Several months ago, with some trepidation and the assistance of a friend who is somewhat more knowledgeable than myself about computer hardware, I took the plunge and installed Linux on my Pentium PC.
Soon after, I downloaded a pile of assorted How-To's, FAQS and Tutorials from the Internet to start doing something useful with Linux. The downloaded documentation was handy but I frequently had trouble finding answers to important questions. After a month I purchased 2 books - Running Linux by Welsh & Kaufman and A Practical Guide to Linux by Mark Sobell. Welsh & Kaufman's Book is a well known, highly regarded, authoritative book on Linux. It is fundamentally about how to set up the major Systems and Hardware and how they interact.
Sobell's book, by way of contrast, approaches Linux from a software perspective. There is little, if any, overlap between the two books, even when they are talking about the same thing. The two books effectively work opposite sides of the Linux street. There is also a contrast in the styles of the two books. Welsh and Kaufman are somewhat "chatty" while Sobell basically tells it like it is with little or no opinion thrown in.
Although there is a chapter on System Administration, Sobell's book concentrates on showing how to use the Linux variants of the standard Unix software packages. There are chapters on X-Windows, vi, emacs, Linux Internet and Networking Software, bash (2 chapters on this important subject), the TC Shell, the Z Shell and Programming Tools.
Learning the bash Shell by Cameron Newham and Bill Rosenblatt (published by O'Reilly) covers the use of bash in more detail than Sobell's book, but I suspect it is a little advanced for the beginner. Sobell's chapters on bash were the most informative and useful information that I have come across so far. Being something of a scripting/batch file afficianado the two chapters on bash provided just the information I needed to produce a host of useful custom scripts.
The Command Summary takes up about a third of the book and maintains the high standards of the rest of the text. Sobell uses internal page references quite freely. This often results in a lot of page turning. I assume this was done to avoid repetition of material, and given the vast amount of material that could be included in a book on Linux/Unix software this is a reasonable compromise as it leaves more room for additional material.
This is not a book for solving Linux hardware or installation problems. If you are looking for that sort of information then get Welsh and Kaufman's book, or download the relevant "How-Tos" (or both). This is the book to use if you want to do learn how to do useful things with the software. The book manages to cover almost all the major software topics, and it covers them well.
I do have some quibbles with the book. The Table of Contents uses a typeface that is much too large, As a result it runs from page xvii to page xlvii. (That's 31 pages for the Roman numerally challenged) Hopefully, the next edition will address this issue.
One notable Linux/Unix Utility not mentioned at all is Perl. A short 5-6 page reference to it in the Linux Utility Program Section or an Appendix would have been nice. Summarising Perl in 5-6 pages is possibly a tall order, but I would have liked some mention or reference to it.
Although the book gives a good rundown on accessing Linux Documentation and Software from the Internet, a Bibliography of Linux/Unix books would have been good. "Running Linux" does have a Bibliography, so if you have that book as well then I guess you have the information anyway (although it's a little out of date).
The book is an adaptation of Sobell's other Practical Guides to the Unix System and this shows, and it's not necessarily a bad thing either. However, given the nature of the Linux community, I doubt whether photographs of a mouse and keyboard are necessary. On the positive side, the book is professionally organized, indexed and referenced. It is substantially larger than the other Practical Guides to Unix by the same author as well.
In the light of the high quality of the book overall, all of the above criticisms are minor and easily overlooked. The book is far and away the best I have seen on the market for quickly and effectively using Linux software. If you have a copy of A Practical Guide to Linux and Running Linux along with a few appropriate "How-Tos", you should be able to get solutions to most of your Linux questions as well as productively use your system.
Sooner or later every UNIX user has a use for a shell script. You may just want to do a repetitive task easier, or you may want to add a bit more kick to an existing program. An easy way to accomplish this is to use a shell script. One of the first shell scripts I wanted was something that would change a directory full of files which were all in capital letters to lowercase. I did it with this script:
LCem.sh
Line one tells the computer which shell to use, in this case it is "sh" the bourne shell ( or this may be a link to the bash shell ). The combination of the two symbols #! are special to the shell and indicates what shell will run this script. It IS NOT IGNORED like other comment lines. Line 3 sets a variable called DIR to equal the first argument of the input. (Arguments start at $0, which is the name of the shell script or in this case LCem.sh ).
In line 5 we enter a control loop. In this case it is a for loop. Translated into english this line means for every entry "a" that I get back from the command `ls $DIR` I want to do something. The shell will replace the variable name $DIR to whatever was typed on the command line for you. Line 6 starts the loop.
Now in line seven we make use of the UNIX utilities available , `echo` and `tr`. So what we are doing is echoing whatever the current value of $a is and piping it into tr which is short for translate. In this case we are translating uppercase to lowercase, and setting a new variable called fname to the result.
In line eight we move the file $DIR/$a, whatever it may be to $DIR/$fname. Line nine tells the shell to go back and do all the other $a variables until it is done. And finally line 10 we exit the script with an error code of zero. Line eleven is a comment.
This script wouldn't have been needed to change one or two file names, but because I needed to change a couple of hundred it saved me lots of typing. To get this to run on your machine you would have to chmod the file to be executable. Like this `chmod +x LCem.sh` . Or you could evoke the shell command directly and give it the name of your script like this `sh LCem.sh`. Using the comment and exclamation mark combination would tell the kernel what shell to evoke and is the normal way to do things. But remember if you use the #! then the file itself needs to have execution permissions.
It is only eleven lines but it shows us a lot about shell scripting. We have learned how to get the computer to run the script using the #! combination. This combination of a comment mark and a bang operator, or as some people call it an exclamation mark, is used to start a shell script without having to evoke the shell first. We learned that a # is how we can write a comment into our script and have them ignored when the script is processed. We learned how to pass arguments to the script to get input from the user, and we know how to set a variable. We have glanced at one of the many control structures we can use to control the functionality of a script.
Don't worry if you didn't really get all of that. We shall now move on to explaining some of the most common decision making / control structures. The first one we want to look at is the `if` statement. In every programming language we want to be able to change the flow of the program based on various conditions. For example if a file is in this directory do one thing. If it isn't do something else. The syntax for the if command is:
if expression then
commands
fi
So if the expression is true the statements inside the if block are executed. Lets look at a simple example of the if statement.
WhoMe.sh
1 #!/bin/sh
2
3 # set the variable ME to the first argument after the command.
4 ME=$1
5
6 # grep through the passwd file discarding the output and see if $ME is in the file
7 if grep $ME /etc/passwd > /dev/null
8 then
9 # if $ME is in the file out put the following line
10 echo "You are a user"
11 fi
Notice the extensive use of comments on lines 3, 6, and 9. You should try to comment you scripts as much as possible because someone else may need to look at it later. In six months you may not remember what you were doing, so you might need the comments as well.
Using the if statement we can now correct some of the errors which would occur in the lowercasing script. In LCem.sh the script will hang if the user doesn't input a directory as an argument. To check for an empty string, we would use the following syntax:
if [ ! $1 ]
This means if not $1. The two new things here are the use of the bang operator, or exclamation mark as the symbol for NOT. So lets add this new knowledge to our program.
#!/bin/sh
1 if [ ! $1 ]
2 then
3 echo "Usage: `basename $0` directory_name"
4 exit 1
5 fi
6
7 DIR=$1
8
9 for a in `ls $DIR`
10 do
11 fname=`echo $a | tr A-Z a-z`
12 mv $DIR/$a $DIR/$fname
13 done;
Now if the user types in the command but not the directory then the script will exit with a message about the proper way to use it, and an error code of one.
But what if we really did want to change the name of a single file? We have already got this command wouldn't it be nice if it could cope. If we want to do that then we need to be able to test if the argument is a file or directory. Here is a list of the file test operators.
Parameter |
Test |
| -b file | True is file is a block device |
| -c file | True if file is a character special file |
| -d file | True if the file is a directory |
| -f file | True if file is a ordinary file |
| -r file | True if file is readable by process |
| -w file | True if file is writeable by process |
| -x file | True if file is executable |
1 #!/bin/sh
2
3 if [ ! $1 ]
4 then
5 echo "Usage: `basename $0` directory_name"
6 exit 1
7 fi
8
9 if [ -d $1 ]
10 then
11 DIR="/$1"
12 fi
13
14 if [ -f $1 ]
15 then
16 DIR=""
17 fi
18
19 for a in `ls $DIR`
20 do
21 fname=`echo $a | tr A-Z a-z`
22 mv $DIR$a $DIR$fname
23 done;
We inserted lines nine through seventeen to do our file/directory checks. If it is a directory we set DIR to equal "/$1" if not we set it blank. Notice we now put the directory slash in with the DIR variable and we've modified line 22 so that there is no slash between $DIR and $a. This way the paths are correct.
We still have a few problems with our script. One of them is that if the file which is getting moved already exists then the scripts outputs an error. What we want to do is check the file name before we attempt to move it. Another thing is what if someone puts in more than two arguments? We'll modify our script to accept more than one path or filename.
The first problem is easily corrected by using a simple string test and an if statement like we have use earlier. The second problem is slightly more difficult in that we need to know how many arguments the user has input. To discover this we'll use a special shell variable which is already supplied for us. It is the $# variable, this holds the number of arguments present on the command line. Now what we want to do is loop through the arguments until we reach the end. This time we'll use the While loop to do our work. Finally we shall need to know how to compare integer values, this is because we want to check the number of time we have gone through the loop to the number of arguments. There are special test options for evaluating integers, they are as follows
| Test | Action |
| int1 -eq int2 | True if integer one is equal to integer two |
| int1 -ge int2 | True if integer one is greater than or equal to integer two |
| int1 -gt int2 | True if integer one is greater than integer two |
| int1 -le int2 | True if integer one is less than or equal to integer two |
| int1 -lt int2 | True if interger one is less then interger two. |
| int1 -ne int2 | True if integer one is not equal to integer two |
Using this new knowledge we'll modify our program.
1 #!/bin/sh
2
3 if [ ! $1 ]
4 then
5 echo "Usage: `basename $0` directory_name"
6 exit 1
7 fi
8
9 while [ $# -ne 0 ]
10 do
11 if [ -d $1 ]
12 then
13 DIR="/$1"
14 fi
15
16 if [ -f $1 ]
17 then
18 DIR=""
19 fi
20
21 for a in `ls $DIR`
22 do
23 fname=`echo $a | tr A-Z a-z`
24 if [ $fname != $a ]
25 then
26 mv $DIR$a $DIR$fname
27 fi
28 done;
29
30 shift
31 done
What we've done here is to insert a while loop on line 9 which checks to see if the arguments listing is equal to zero. This may seem like we just created an infinite loop but the command on line 30 the shift saves us. You see the shift command basically discards the command nearest the command name. (LCem.sh) and replaces it with the one to the right. This loop will succeed in discarding all the arguments eventually and then will equal zero and exit our loop.
And finally note the if statement on line 24, this checks to see if the file name is already lowercase and if so ignores it.
I hope you have enjoyed this brief introduction to Bourne / Bash programming. I would encourage you to try some of these examples for yourself. In fact if you want you could make this script much better by using a switch like -l to lowercase and -u to uppercase and modifying the script to handle it.
I take full responsibility for any errors or mistakes in the above documentation. Please send any comments or questions to
REFERENCES:
The UNIX programming environment
by Brian W. Kernighan & Rob Pike
Published by Prentice Hall
Inside UNIX
Published by New Riders
Here's this month's account of the triumphs, trials and tribulations that I caused myself or encountered since the last time, and a couple tips that may come in handy and increase your understanding of linux.
If you adopt the strategy of selective backups, you can easily fit them on a floppy or three, rather than using a whole tape or zipdisk to backup what you have already on your installation media. I think that especially if you installed from a CD, the plain vanilla install like you did the first time, can put you back on your feet when combined with a backup of only those files you wrote or modified, and and any special software that wasn't included in the distribution. To find out what files and libraries are required to run an app, you can use
ldd filename
Another command that you can use to find out more about files is, strangely enough, file. File can be used as
file filename
which will give information about other files, as well as executables. Yet one more helpful command is which, used like
which executable
where executable is the command used to start the application as in
which makewhatis
to find out where the executable is located, pretty handy if you are modifying your path statement.
I stress this because I know from experience that failing to backup your data is an extremely stupid and easy thing to do, but since I apart from the cardiac care unit and the nuclear reactor I don't have anything mission critical on my box right now, I'm still too lazy to back it up. Please excercise a little cautious computing if anyone's data needs to be secure
Exec "PROGNAME" exec progname -options &
the "&" causes the program to execute in the background, which keeps it from monopolizing X. Note that some apps, such as ImageMagick don't seem to want to share, and those will have to be exec'ed without the "&". Also non-X apps can usually be run by invoking an xterm or rxvt, in which case the titlebar can be changed to reflect the program name, as in
Exec "Top" exec color_xterm -font 7x14 -T Top -n Top -e top &
which starts a color_xterm running top. Top, in case you aren't familiar, basically lists the amount of resources each process is using. For more info type
man top
or better yet just type
top
Some examples:
cat filenamehere>>anotherfile
This one will add the contents of one file to another file, as in chapters 1 and 2 could be added together for reasons of continuity to make a fluid read that would otherwise be broken up by having to cat the successive chapters
cat hellaracket.au >/dev/audio or /dev/dsp
is another example of redirecting the output of a command or file to somewhere other than standard output which is another way of saying your monitor.
Another feature is command line batching of commands. If you type several commands separated by semicolons, each command will execute when the previous one exits. A good example, is:
make config; make dev; make clean; make zImage
which will perform each of the steps necessary to compile a kernel. As soon as the first command exits or is closed, the next one starts Any group of commands that you would like to run in succession can be done in this manner.
Another device you can use to your advantage with a little imagination is the pipe, signified by the "|" symbol. Pipe is a pretty good description of what it does, which is to "pipe" the output of one command into another command for further processing. One example that springs to mind is
cat filename | pr -l56>/dev/lp0
which come to think of it, is another example of redirection as well. The above command takes the results of the cat command pipes it to a filter "pr", and redirects the output to /dev/lp0 to print a file in a reasonably attractive manner. For some of the options available to "pr", try
man pr
This filter is particularly useful if you find lpr to be beyond your present capability, as I have :(. You should be aware however, that this will only work as root, or with a lot of permission hacking, which is probably best left undone, as it can cause security problems if /dev/lp0 is made available to regular users.
s2:12345:respawn:/sbin/agetty -L 9600 ttyS1 vt100
if modified to reflect the serial port used, in this case com port 1 in DOS lingo. This line can also be used with a 8086 or above to emulate a serial terminal, if used with the proper cable. The proper cable, usually called a null modem, is often sold as a serial printer cable.
A serial terminal is a very good option when used with a Linux box as it allows more than one user on the system at a reasonable cost compared to buying another computer. The local university surplus disposal has them for about $25US, and you may find them for free. 8086, 8088, and 286 boxes, which will also serve the purpose can be gotten just as cheaply, depending on what hardware is attached. The other thing you need is a comm program, Minicom and Kermit are two that spring to mind or perhaps Seyon if you're in X. I've never used any of these programs to connect directly to another computer as a terminal without a modem, so I don't know much about connecting with minicom in this manner, but Kermit seems to be pretty simple in this capacity Another use is to kill frozen X applications. I had a Netscape bus error problem before I got Andreas Theofilu's nets , and a terminal can be used to kill out of control processes quite easily, by logging in and using kill or similar(remember die?)command to wax it and you can regain your X session. Nearly any non-graphical task you can do on the console can be done on a serial terminal. One exception, virtual terminals can be worked around to a degree by usingsplitvt which cuts your screen into two parts and by using
CTRL-Wyou can switch between the upper and lower displays, and work alternately between the two, with the added advantage of seeing both screens at once. You can even be root on one while using a different account on the other screen, easily cut and paste from one editting session to another, check top or ps or many administrative tasks that require monitoring. It ain't X but it's pretty good for a text only environment.
See you next month!
Once upon a time, in a land far, far away...
Someone once told me that phrase was the perfect way to begin a story with a happy ending. If so, then I am inclined to employ it here.
It has been over 20 years since my first programming experience. An ASR-33 Teletype with a paper tape punch attached to an acoustic coupler (do they even tell today's Computer Science students about the joys of a 110 baud acoustic coupler?) would whir, clunk, chunk, and ding as it magically made my dry, clinical code come to life and perform wonderful tasks! Amazing! And, I was told, the wondrous machine miles away on the other end of the telephone could not only breath life into my coded creations, but it could simultaneously do likewise for dozens of other aspiring Dr. Frankensteins who, like me, wanted to see dry, dead algorithms transformed into living, breathing computer creations.
That's how it all started. In retrospect, it involved a dreary little teletype in a bleak little room connected to a slow little coupler (for you recent CS grads, that's a modem that connected to a phone using an acoustic cradle rather than today's direct modular phone wire) connected over a telephone line to a computer that probably didn't have the computational power of a modern programmable pocket calculator. By today's standards, it was a trivial computing experience. But it shaped my perspective on computing forever, because that ancient assembly of antique parts could not only perform computations, but it could support multiple concurrent users. It did something that those of us with grey in our hair used to refer to as "timesharing".
When I went to college, I was exposed to and learned the internals of a DEC PDP-11/34 running the RSTS/E operating system. Another fine timesharing operating system, RSTS/E happily supported an entire campus population with a mere 124K words -- just 248K bytes! -- of usable memory and 12.5M bytes of hard disk storage! But this Resource Sharing Time Sharing / Extended system made each user feel like they had a whole computer at their beck and call. It was a marvelously reliable workhorse that ran for days without crashing, even while hordes of unthankful students stretched it to its very limits on a daily basis.
Soon after I entered the business world, I met another highly impressive operating system. It was called DEC VAX/VMS. It was an iron horse of a operating system that was seemingly massive in its internal complexity, yet uniform in its appearance. When properly tuned, a VAX/VMS system could satisfy the needs of dozens or even hundreds of concurrent users for months on end. Even now, Digital's OpenVMS (the current incarnation of VAX/VMS) can run for years between reboots faithfully servicing the needs of its users.
It was here that I settled down. It was here I dug in. Nestled safely in the FABs and RABs and QIOs of OpenVMS internals, I settled in for a long, comfortable stay. Where else would a programmer rather go? Here was reliability. Here were strong multiuser capabilities. Here were documented system calls... uniform presentation... true upgradability... all found in a system that just wouldn't quit!
I was home!
Yes, I knew there was more out there. There were all those mainframes. But who the heck wanted to work with IBM? They were on top. They were the Big Corporate standard. They were the "safe choice". What fun was that?
Then, there was Unix. Or, shall I say, the plethora of Unix-like systems. Each different. Each ugly. Commands that made no sense. Non words like "grep". What's a "grep"? Editors named after people's initials. Uck. Phewy! Give me commands like SEARCH and EDIT any day.
Then, of course, came the ground swell which was dubbed the "PC revolution". Here, at last, was computing for the common man. You could have your own system with your own software to do your own work. Magnificent concept, but the tools... yow! The popular PC operating systems were so anemic. Remember, these operating systems were responsible for the word "reboot" entering common speech. They were lucky if they could accomplish one thing at a time, let alone serve the needs of hundreds of people simultaneously.
Yes, color and sound became standard through the PC influence, but so did the notion that an operating system could have a nervous breakdown whenever it pleased. With the introduction of these systems into the business realm, the bar of technical excellence for operating systems plummeted to previously unimagined lows. Amidst the growing cry for open standards, the PC's proprietary operating system with undocumented system calls inexplicably soared in popularity. Suddenly, interface was everything. Reliability was nothing.
Yet, though I tinkered with the PC at home, I was happy to continue my work with solid, feature-rich OpenVMS. Then, one day, it happened. I was attending training on migrating software from OpenVMS to Unix (ugly though it was, at least Unix was a product of people who knew what it meant to have a reliable operating system). I picked up a mail order catalog and there was an ad for an inexpensive PC-based Unix called Linux. I passed it around during class and by the end of the training session, there were several people intending to purchase this product as a means of brushing up on Unix skills.
That's how I came to use Linux. After the class was over, I ordered a copy of Yggdrasil Plug-and-Play Linux (Nov 1994; kernel version 1.1). At first, I created an 80 MB partition on my 386SX/40 and ran most of the operating system off of the CD. The few people I found who knew of the operating system said it was "still a bit buggy, but cool". I quickly found out that a "buggy" Linux was still more stable than the more "mature" PC operating systems I had been fiddling with.
One of my first practical uses for Linux presented itself during a 2 week intensive training course I needed to attend. As I wanted to touch base with my wife daily, but knew that the schedule could make it difficult for us to connect on the phone, I decided to set up my little Linux box as a mail server during the training. I created a turnkey account and menu for my non-technical wife to create and read mail messages on the box at home, while I would compose my mail messages on my laptop and dial in to my home system to upload and download my mail. Much to my amazement, my limited little 386 turned out to be a marvelous little mail hub. This lowly little box, which many would dismiss as having insufficient resources to perform any serious computing, was suddenly transformed into a true multiuser system which easily handled the task of being a miniature mail hub!
I soon discovered that there were familiar friends available to help me get acclimated to my new O/S. On the Web, I found Anker Berg-Sonne's SEDT editor to give the EDT emulator I desired. I also found source code for an implementation of the TECO editor which compiled nicely under Linux. Suddenly, I was ready to give programming a try in this "new world" I had discovered.
The robust GNU C compiler proved to be a rich engine for developing software. Coupled with the XFree86 software that provides the standard X windows interface, I soon found that the Linux environment was a splendid development platform for producing some 3D object rotation software that was requested by one of my clients. Even though the target system was an OpenVMS workstation, I found that I could port the software I developed under Linux by simply changing a couple of #include directives. Wow! I now had the ability to create and run workstation software on a low-end PC!
But that was only the beginning. Soon, I upgraded my system and made the strategic decision to allocate a large portion of my new disk drive to Linux. That is one decision I have never regretted. The operational advantages of my new platform were becoming more and more significant.
Like any PC, my Linux box enjoyed numerous inexpensive hardware options. Yet, unlike most PCs, this operating system could really perform multiple tasks simultaneously. And, unlike most PCs, I didn't have an operating system that needed constant rebooting. I could develop and run software based on open standards without having to focus on proprietary system calls. I could employ a TCP/IP stack that was sure and solid. And, I had the power of a true multiuser, multitasking operating system.
Then came the 1997 Atlanta Linux Showcase. I talked my manager into letting me attend it as a training event. Suddenly, I was surrounded by hundreds of people who were even more enthusiastic than I. Amidst the technology and training, there was passion and conviction. I discovered that Linux wasn't merely the pleasant pastime of a few hackers; it was the growing wave that was beginning to wash over the beaches of corporations worldwide. Listening to the impassioned appeals of people like maddog Hall, Eric Raymond, and Robert Young, I was affected. The software paradigm was changing, and I had to find my place in this new world.
At work, I liberated an old 486 languishing in a corner and turned it into a intranet web server. It had been considered too weak for most "serious" PC applications, yet it has plenty of horsepower to serve as my personal workstation, intranet ftp server, and intranet web server. Its intranet web pages are dedicated to Linux advocacy, attempting to convey, convince, and convict folks within the corporation that Linux is a new market that will not be ignored. In its first 6 months of operation, the server has processed requests for over 3300 HTML pages. In all that time, the system has never crashed due to software (we had a power outage once), and at one point the system exceeded 10 weeks between reboots (I have had to shut it down for hardware upgrades and environmental reasons).
I have used Linux to develop software for US government customers, both on site and off. It has proved to be an extremely capable development platform for software destined for OpenVMS, Digital UNIX, and even Windows NT. Linux's adherence to industry standards makes it an excellent base for designing portable software. Plus, the addition of exciting technologies like KDE and GNOME bring the concept of a user-friendly desktop to a POSIX-compliant system. Who could imagine the day of a sharp looking Unix desktop that even the most hesitant end-user could conquer?
Today, Linux is my preferred platform, both at work and at home. I still have a deep fondness for the robustness of OpenVMS, but I relish the possibilities of an operating system that can scale from a lowly 386 to a networked army of thundering Alphas.
I do not know all that is ahead for Linux, but I'm tempted to invoke the normal conclusion for all good stories:
... and they lived happily ever after!
This column is devoted to making the best use of Emacs, text editor extraordinaire. Each issue I plan to present an Emacs extension which can improve your productivity, make the sun shine more brightly and the grass greener.
Jka-compr is a package written by Jay K. Adams which allows Emacs to handle compressed files transparently. When you open a compressed file, Emacs will automatically decompress it before displaying it. If you make changes and save the file, it will be compressed transparently before being written to the disk. To enable jka-compr, just add the following line to your emacs configuration file (normally called ~/.emacs) :
(require 'jka-compr)
jka-compr works by looking at the filename extension, and in its default configuration recognizes .gz (gzip), and .Z (compress) files. It also recognizes the extension .tgz and unzips tarballs before passing them to tar-mode, which lets you look inside tar files. If you use other compression programs you can tell Emacs about them too, for example to use Julian Seward's bzip2 (faster and slightly better compression than gzip, under GPL) you could add the following to your .emacs (before loading jka-compr)
(setq jka-compr-compression-info-list
'(["\\.Z\\(~\\|\\.~[0-9]+~\\)?\\'"
"compressing" "compress" ("-c")
"uncompressing" "uncompress" ("-c")
nil t]
["\\.tgz\\'"
"zipping" "gzip" ("-c" "-q")
"unzipping" "gzip" ("-c" "-q" "-d")
t nil]
["\\.gz\\(~\\|\\.~[0-9]+~\\)?\\'"
"zipping" "gzip" ("-c" "-q")
"unzipping" "gzip" ("-c" "-q" "-d")
t t]
["\\.bz2\\(~\\|\\.~[0-9]+~\\)?\\'"
"bzipping" "bzip2" ()
"bunzipping" "bzip2" ("-d")
nil t]))
Packages like jka-compr are written in Emacs Lisp; you can read the source code in the directory /usr/local/lib/emacs/${VERSION}/lisp/jka-compr.el for GNU Emacs, or /usr/local/lib/xemacs-${VERSION}/lisp/packages/jka-compr.el for XEmacs users (if you are using a Red Hat Linux distribution, you need to install the emacs-el package to see the source files). How can they change the behaviour of Emacs at such a low level as reading and writing files? The answer comes from the concept of hooks.
Most of Emacs' low-level functions (which are written in C) have an associated hook, to which user-level functions (written in Emacs Lisp) can be attached. Hooks are fundamental to the customizability of Emacs, allowing users to override default behaviour in ways that its developers could not have imagined. Hooks are explained in the Emacs and Elisp manuals, which are available online from within Emacs by typing C-h i (or from the Help menubar or (blech!) the XEmacs toolbar).
As an example of using a hook, the after-init-hook is run right after Emacs is lauched and has loaded your initialization file. Let's say you want Emacs to tell your fortune each time you start it. Just add the following lines to your .emacs :
(add-hook 'after-init-hook
(function
(lambda ()
(pop-to-buffer (get-buffer-create " *Fortune*"))
(shell-command "fortune -a" t))))
In the next issue I'll discuss ange-ftp, which lets Emacs see the Internet as a huge virtual filesystem. Please contact me at <[email protected]> with comments, corrections or suggestions. C-u 1000 M-x hail-emacs !
PS : Emacs isn't in any way limited to Linux, since implementations exist for many other operating systems. However, as one of the leading bits of free software, one of the most powerful, complex and customizable, I feel it has its place in the Linux Gazette. Don't forget, Emacs makes all computing simple :-)
Being the curious type, I sat down to write a program that would gather usage information. The information I wanted includes:
My second thought was to use the "w" command. This command reads a log file (normally /var/log/wtmp) and produces a line of output for every logon event in the past, describing who was logged on and for how long. My hope was that a summary of this information would provide the usage statistics I was looking for. Unfortunately, this command does not produce foolproof output. If the machine crashes while someone is logged on, then "w" will sometimes produce the wrong total time online. Even worse, if a person is logged on but idle, this idle time still counts as usage as computed by "w".
Counting idle time was unacceptable to me. We have several users with computers in their offices, and they are essentially logged on 24 hours per day 7 days per week. Their usage is nowhere near this level (yes, even college professors go to sleep!)
Luckily , there was an alternative to "w". The easiest way to find out who is currently logged onto a computer is to use finger, a program designed for just this purpose. The command "finger @hostname" will describe who is logged on to "hostname", and how long since they actually typed a command (i.e. finger knows their idle time).
Finger produces a header line, and the one line for every person logged on. Eliminating the users with a high idle time will provide a list of users who are using the computer at any given moment. A log file of such lists, gathered at regular intervals, will describe usage over the time the log file was gathered.
There is an important statistical assumption here. We assume that a set of entries will accurately describe usage over the whole time period, not just the precise moments when those entries occur. For this assumption to be valid the entries should be gathered at regular intervals.
| Date 97 10 11 23 45 Host ogimaa 1 Host bine 0 Host gaag 0 Host makwa 0 Host mooz 0 Host zagime 0 Host ogaa 1 Host euclid 0 Host euler 0 Host fermat 0 User randy User root Total 2 users |
There are two basic tasks of fingersummarize. These functions could easily be done with two separate programs, but I find it easier to have one program with options rather than two executables.
|
Stats by user User Total Usage Hours Name Observ. Percent /Day abasosh 47 4 0.42 agdgdfg 54 4.6 0.49 arnelso 7 0.6 0.06 bparton 2 0.1 0.01 bob 28 2.4 0.25 brandk 101 8.7 0.92 btsumda 37 3.2 0.33 chgijs 1 0 0 clntudp 1 0 0 daepke 2 0.1 0.01 dan 93 8 0.84 dfliter 17 1.4 0.15 gclas 43 3.7 0.39 goofy 15 1.3 0.13 gypsy 2 0.1 0.01 jadsjhf 2 0.1 0.01 jbsdjh 2 0.1 0.01 jdefgg 2 0.1 0.01 jeffpat 6 0.5 0.05 jpaulin 7 0.6 0.06 jstyle 4 0.3 0.03 jstamo 17 1.4 0.15 jwilpin 37 3.2 0.33 jwilpou 79 6.8 0.72 kangol 39 3.3 0.35 matt 58 5 0.52 mhgihjj 8 0.6 0.07 randy 187 16.2 1.7 rbush 2 0.1 0.01 root 22 1.9 0.2 rpijj 2 0.1 0.01 sbeyne 17 1.4 0.15 sdajani 1 0 0 sdalma 28 2.4 0.25 ship 1 0 0 skinny 48 4.1 0.43 stacey 2 0.1 0.01 tbutler 35 3 0.31 tmarsha 5 0.4 0.04 tpauls 34 2.9 0.31 vladami 30 2.6 0.27 xetroni 26 2.2 0.23 --------------------------------- Overall 1151 10.24 Stats by Host |
Stats by the Week Week User Starting Hours 97 10 04 74.5705816481128 97 09 28 55.9130434782609 97 09 21 64.7 97 09 14 113.023956442831 Last Two Weeks Stats by the Hour |
 |
|
 |
muse:
 elcome to the Graphics Muse! Why a "muse"? Well, except for the sisters aspect, the above definitions are pretty much the way I'd describe my own interest in computer graphics: it keeps me deep in thought and it is a daily source of inspiration.
|
his column is dedicated to the use, creation, distribution, and discussion of computer graphics tools for Linux systems.
 |
 |
|||
Play Video CDs with MpegTV PlayerMpegTV is happy to announce that is it now possible to play Video-CD's (VCD's) on Linux-x86 systems with MpegTV Player 1.0 and xreadvcd.MpegTV Player 1.0 is shareware (US$ 10) for personnal and non profit use only. Commercial licenses are required for commercial or governmental use. xreadvcd is a free utility developped by Ales Makarov (source code available). For information and to download MpegTV Player and xreadvcd: To receive announcement of new MpegTV product releases you can subscribe to our mailing list: Contact information: |
|
Xi Graphics announes Virge GX/2 supportXi Graphics, Inc. announces support for the Virge GX/2 in their Accelerated-X Display Server v4.1 for Linux, FreeBSD, BSD/OS, Sun Solaris/86, Interactive, Unixware, and SCO OpenServer V. XiG has full 2D acceleration in all color depths and resolutions. XiG also supports hardware gamma correction.For current users of Accelerated-X Display Server v4.1 there is now an update_4100.016 on their FTP site which contains new support for the Virge GX/2 (AGP & PCI) video cards, this update includes specific support for the Number9 Reality 334 video card. The update also contains enhanced support for the previous Virge GX and DX video cards. For a demo of the Accelerated-X Display Server v4.1 download the demo and these updates: ftp://ftp.xig.com/pub/update/ If you have a graphic card with troubled support contact XiG. They may have a server that fixes your problems. |
|
|
|
||
TrueType to Postscript font converterAndrew Weeks has written a program to convert True Type fonts to Postscript, so Linux users can use the TT fonts that come with Windows.See http://www.bath.ac.uk/~ccsaw/fonts/ |
OpenGL Widget for GtkgtkGL version 0.2 is a function/object/widget set to use OpenGL easily with GTK. gtkGL includes gdkGL; GLX wrapper.List of current archives appears to be at MindsEye mailing list archiveshttp://mailarchive.luna.nl/mindseye/ |
||
|
|||
Freedom VR 2 adds many features to Freedom VR 1 -- it's now possible to embed hyperlinks in your VR scenes as well as to make scenes with two dimensional navigation -- where you can drag the object up and down as well as left and right. Users can now navigate via the keyboard, and Freedom VR 2 can now be controlled by Javascript. In addition, Freedom VR 2 has some improvements in cross-platform performance.
Freedom VR 2 is easy to use; many people have already made great content with Freedom VR 1 -- to encourage people to use Freedom VR 2, we're sponsoring a contest. We're giving away a free virtual pet to the person who submits the best VR model before December 15, 1997. Take a look at http://www.honeylocust.com/vr/
Editor's Note: Ok, so I didn't get this out in time for the contest. My apologies.
|
Brother HL 720 Laser Printer driver for GhostscriptP.O. Gaillard wrote a Ghostscript driver for the Brother HL 720 laser printer. He submitted it to Aladdin Enterprises and it should be included in upcoming versions of Ghostscript (i.e. the ones coming AFTER 5.10).This driver is completely free from copyrights by Brother or Microsoft (the printer is not a true WPS printer, which is why he could obtain documentation). You should note that such documentation is not available for Oki and Canon (LBP 660) printers which prevents writing drivers for them. Some facts about the driver and the printer People (especially maintainers of Ghostscript packages for commercial distributions) who want to use the driver with gs3.33 can contact Mr. Gaillard and he will send them a patch. (The patch has already been posted in fr.comp.os.linux a few months ago). Maybe normal users can wait for Debian and Red Hat packages.
Ed. Note: this was an old announcment from comp.os.linux.announce. I don't have any other contact information except for the email address. VARKON V1.15CVARKON is a high level development tool for parametric CAD and engineering applications developed by Microform, Sweden. Version 1.15C of the free version for Linux is now available for download at:http://www.microform.se For details on what's new in 1.15C check: Johan Kjellander, Microform AB |
|
Awethor - Java Based authoring toolCandleWeb AS is proud to announce a new Java based authoring tool called Awethor. Awethor strives to meet the needs of web authors when it comes to designing and creating graphics for the Web. As the Awethor system uses vector graphics rather than bitmaps, users can create and publish large scale drawings and animations in small files, thereby avoiding the large download times traditionally associated with large web graphics and animations.The output of Awethor can be run in any browser that supports the Java language. Awethor typically outputs two files :
http://www.candleweb.no/ |
|
FREEdraft is licensed under the GPL. Feedback is appreciated. The source code and a screen shot is available from http://www2.netcom.com/~iamcliff/techno.html
|
WebMagick is a package which makes putting images on the Web as easy as magick. You want WebMagick if you:
The primary focus of WebMagick is performance. Image thumbnails are reduced and composed into a single image to reduce client accesses, reducing server load and improving client performance. Everything is either pre-computed or computed in the browser.
Users with JavaScript-capable browsers (Netscape 3 or 4 & Internet Explorer 4) enjoy an interface that minimizes accesses to the server. Since HTML generation is done in the brower, navigation is much faster and more interactive.
During operation WebMagick employs innovative caching and work-avoidance techniques to make successive executions much faster. WebMagick has been successfully executed on directory trees containing hundreds of directories and thousands of images ranging from tiny icons to large JPEGs or PDF files.
Here is a small sampling of the many image formats that WebMagick supports (48 in all):
Obtain WebMagick from the WebMagick page at http://www.cyberramp.net/~bfriesen/webmagick/dist/. WebMagick
can also be obtained from the ImageMagick distribution site (or one of its mirrors) at ftp://ftp.wizards.dupont.com/pub/ImageMagick/perl/.
|
A: Actually, I'm not completely sure about the legal differences, but I'll tell you what I know and how I interpret it. First, the Gimp core program is licensed under GPL. The Plug-Ins (as of the 0.99.18 release) are licensed via the Gimp API library they use which is called libgimp. This library is licensed under the LPGL. GPL - the GNU General Public LIcense - provides that the program may be modified and distributed by anyone as long as the changes are distributed with the source. This means, I believe, that you can sell the Gimp if you want but that you need to distribute it with the source code, including any changes you may have made to the program. It also means that the code in the Gimp's core cannot be incorporated into proprietary programs - those programs would have to fall under the GPL if they used any of the Gimp's source code directly.
The Plug-Ins differ from this in that they can be commercial applications, distributable without source code. They link against libgimp (and the Gtk libraries, which are also LGPL'd) but do not use any of the core Gimp code directly. The LGPL appears to cover the libraries distribution rights, but allows proprietary programs to link against the library with certain restrictions.
At least thats how I interpreted it.
|
In going through some old email, I found the following discussion which took place in early November 1997 regarding the use of RIB shaders with BRMT. Being a little short on real subject matter this month, I thought I'd share it with you.
Ed Holzwarth () initially wrote:
Partial RIB code
AttributeBegin
Attribute "identifier" "name" [ "ball" ]
Interior "shaders/hsin"
Surface "shaders/trans"
Translate 2 0 6
Sphere 3 -3 3 360
AttributeEnd
.sl code
volume hsin ()
{
if (sin (xcomp(P)) > 0)
{
Oi = .5;
Ci = color (0,.8,0);
printf(".");
}
else
{
Oi = 0.8;
Ci = color (.5,0,0);
printf("!");
}
}
/* transparent shader */
surface
trans ()
{
Oi = .2;
trace(P,normalize(I));
printf("After : Oi = %c, Ci = %c\n",Oi,Ci);
}
Hmmm. I haven't been playing with BMRT for some time now and was no expert to begin with, however I think the problem might be fairly straight forward. I played with what you sent me by shoving it in a standard RIB that I use to test objects and shaders. I played with lots of settings in the RIB for colors and opacity. No real help there. Then I tried mucking with the two shaders. Not much luck there.
So I thought about what the volume shader really does. A volume shader does not have a geometric primitive associated with it. It is bound to a surface. So thinking about this and looking at how the surface was defined via the RIB and the surface shader I thought "Gee, maybe the surface isn't of a type that can allow light to pass through it very well, even if we've set the opacity low". So I swapped your surface shader with the BMGlass shader I got from a web site (or maybe it was from Larry Gritz's pages, I've forgotten now - the shader was written by Larry).
Success. The effects of the volume shader are properly displayed using the glass surface shader. Or lets say the colors you'd expect from the volume shaders impact are obvious and distinct. The old way, all I got was various forms of reflection from the surface. Now I get the surface mixed with the volume shader effects.
I don't know if this is the correct solution to your problem, but I think its a start. The volume shaders effects are tightly bound to how the light enters that volume, and that is determined by the characteristics of the surface through which the light must travel. Muck with the surface characteristics (or use a clear glass shader if you don't want the surface to play a role in the overall effect) first, then fiddle with the volume shader.
Ed wrote back:
Partial RIB code
AttributeBegin
Attribute "identifier" "name" [ "ball" ]
Surface "shaders/trans"
Interior "shaders/hsin"
Opacity [0 0 0]
Translate 1.9 0 6
SolidBegin "primitive"
Sphere 3 -3 3 360
SolidEnd
AttributeEnd
Shader code
/* transparent shader */
surface
trans ()
{
Ci = trace(P,I);
}
volume hsin ()
{
color Cv, Ov;
if (sin (2*xcomp(P)) > 0)
Cv = color (0,length(I)/8,0);
else
Cv = 0;
Ov = length(I)/8;
/* Ci & Oi are the color (premultiplied by opacity) and opacity of
*the background element.
* Now Cv is the light contributed by the volume itself, and Ov is the
* opacity of the volume, i.e. (1-Ov)*Ci is the light from the background
* which makes it through the volume.
*/
Ci = Cv + (1-Ov)*Ci;
Oi = Ov + (1-Ov)*Oi;
And another from the really old email category:
Rob Hartley < or > wrote:
The problem with OIV is that it costs nearly a thousand dollars U.S.! A bit much when I consider that I can get a whole new Linux box for that much, or for the price of a new souped up PC and OIV, we can get a second-hand SGI workstation which comes with Inventor pre-installed.
So I scrounged the 'net a bit and found Links to the 'Apprentice Project' and 'Pryan' which runs under the QT GUI library. Both of these packages, available in source form, will read Inventor files, which is really nice, because Inventor files are/were the basis for the VRML 1.0 file definition. This I find particularly handy for developing applications at work and at home. At work we have a mix of SGI, AIX, HP, and Sun workstations pumped up and running Catia for our design group (we build gas turbine engines for jets, helicopters and commuter aircraft.)
Which brings me to why I am writing: In the Linux Gazette I noticed a query about: "...PC software product -- an interactive educational system -- what PC graphics package is "state of the art" for Linux or Windows?" If I were tasked with developing an interactive 3D system that had to be run on Linux, Win'95/NT and a large variety of Unixen (Unixes, Unicses?), I would be tempted to look further into the following:
Open Inventor
 |
|
||||||||||||||||||||
Font3D and XFont3DOne of the problems with using 3D graphics for logos is the lack of good model data for the fonts. A quick scan of the various model banks, such as Viewpoint Datalabs Avalon archives or 3DSite, finds very few canned models of fonts. Besides, do you really want to hang on to a complete set of letters in a given font as model data? After all, how often will you be using X, Q or Z? (Of course, cyberworld artists probably use these all the time, but thats another story).Fortunately, this problem is easily solved using Todd Prater's Font3D utiltity. Font3D is a tool for converting text strings using a given font into model data which can be read by a variety of modelling programs and rendering utilities. Output formats include support for POV-Ray (both 2.x and 3.x formats), Raidance, Vivid, AutoCad DXF, Renderman RIB, and RAW Triangles. The model data can be generated using a healthy set of Font3D command options. Features such as face textures, beveling of both front and back faces, length of face and side cuts for beveling, and object positioning are provided. Font3D supports both Macintosh and MSWindows TrueType font files. Font3D is, I believe, shareware. The register.txt file states it runs for $10US, although it doesn't state explicitly that you need to register. Since the files in the latest version, 1.60, are dated with a January 1996 date, I suspect that either no new work has been done on Font3D in some time or only registered users are getting updates. Then again, once you've seen the breadth of command options avialable, you might wonder what new features could be added. You can fetch the C++ source for Font3D from its primary archives at http://www-personal.ksu.edu/~squid/ font3d.html. You can also fetch a slightly older version from the POV-Ray archives at ftp://ftp.povray.org/pub/poray/utilities. This latter version is th 1.51 version. I'm not certain why, after all this time, the 1.60 version has not been added to the POV-Ray archives. Also note that the 1.51 release includes a large DOS and OS/2 binaries in the zip file, along with the C++ source. The 1.60 release broke out the DOS and OS/2 binaries and includes only the source. The source for 1.60 comes in a zip file. If, like me, you are unfamiliar with C++, don't worry. The Makefile provided builds the source without modification. There really isn't all that much to the source, which makes dealing with the build all that much simpler. The Makefile assumes you have GCC/G++ installed and in your path. For Linux users this is pretty much a given, especially if you've installed from one of the well known Linux distributions (Red Hat, Debian, SuSE, Slackware, etc.). Basically, just follow the installation instructions for Unix systems that can be found in the font3d.txt file, or if you prefer, in the font3d.ps document. The code appears quite stable, producing usable code for both POV and RIB (via BMRT) as well as DXF and RAW files that were parsable by the latest version of the AC3D modeller. Font3D processes a specified string using a specified font by parsing a set of commands. These commands can be specified either on the command line or in a configuration file. Command options fall into 8 basic categories:
For bash/ksh/sh users:
FONT3D_DEFAULT_CONFIG=<path>/<config_file_name> For csh users:
export FONT3D_DEFAULT_CONFIG
setenv FONT3D_DEFAULT_CONFIG <path>/<config_file_name>
If a path is not specified, the default config file (font3d.def) will be searched for in the same directory from which you started Font3D. Note that the FONT3D_DEFAULT_CONFIG variable specifies the path and file name, not just the path, to the config file.
Commands are formed as "name=value" pairs, whether they are in the config file or on the command line. If the "value" portion of the command includes spaces it must be enclosed in double quotes. This is probably only applicable to the string command, which is used to specify the text for which the objects will be generated. By default Font3D uses POV-Ray as its preview renderer, which means the default output file will be a POV-Ray include file. Object naming is supported for POV objects, although no other output formats allow for naming of objects. Font3D also uses a right-handed coordinate system by default. This can be changed with the coordiante-system command line option. Note that POV-Ray, for example, uses a left handed coordinate system. I would think it would make more sense to make the default left handed since the default output is POV-Ray. Strings are generated by default, but you can specify a single character using the char command. You can also specify a character code of a single glyph using the code command. Texturing is only supported for POV output formats. The texture is referenced by name only, by applying the named texture to the object. Font3D cannot be used to generate a texture directly. The visibility commands only determine if a component (front face, a bevel, etc) will be displayed in the rendered image. If the visibility for a component is turned off, the component is still generated as part of the object in the output file. This means turning the visibility off for various components will reduce the polygon count for your objects. It does not turn off the actual beveling, however. If the cut for a face or side is non-zero, then the bevel will still be there except with the visibility turned off the object has a gap where the bevel would have been.
|
|
More Musings...
|
||||||||||||||||||
|
||||||||||||||||||||
Bevels, sides and faces are better understood with a simple diagram:  As you can see, it is possible to set quite a few characteristics of the objects generated. You can't use the rounded beveling features of Font3D to create completely rounded lettering, however. The beveling (whether using rounded or flat bevels) work best as subtle effects on the lettering. This is because the rounded beveling is done using smooth triangles on a flat bevel, which only fake the rounded appearance by altering the normals at the points of triangles. I covered this type of problem when discussing BMRT's support for True Displacements in the May 1997 Graphics Muse article titled BMRT Part II: Renderman Shaders. Also, not all formats support the smooth triangles. Despite this, smooth triangles are the default (POV-Ray) does support them) and are recommended for final renderings. Previews can be run without them, of course, to decrease rendering time. The output from Font3D is prefixed with comments, as shown in font3d-1.txt. This makes it easy to determine how to reproduce the objects should the need arise. You can view the actual object code by viewing the example POV-Ray 3.x and RIB files. These are abbreviated, sample files, since the complete files were over 700k. Notice that the RIB file is in a format where it can be included using the ReadArchive command. The samples generated produced the following images:
Font3D comes complete with very good documentation in both regular text and a postscript version which prints out to 30 pages. The document includes a very thorough description of all command line options. Although Font3D offers many wonderful features, it can be cumbersome to remeber how to use them all. Thankfully, has added an X-based front end to Font3D which he calls XFont3D. XFont3D is an XForms based front end that includes a POV preview capability. That means it understands how to run POV, but not any of the other supported formats supported by Font3D. 
Using this interface is pretty straightforward as long as you understand the Font3D command structure. Clicking a button under the options header on the right of the window causes the framed area to the left of that to be populated with relevant buttons and input fields. Many of these options can be reset to their default values using the small, square buttons with the black dot in them (just click on it once). In general, you'll want to choose a font first (using the font button to access a file selection window), specify the string to generate and an output file name. AFter this you can specify configuration options and an output file format (RIB, POV, etc). Changing the map type (MS, which should really be PC to avoid annoying Unix traditionalists like myself, or MAC) or the Cooordinate handedness probably won't be necessary that often, but that depends on your own needs. |
||||||||||||||||||||
|
||||||||||||||||||||
 |
|
Linux Graphics mini-Howto Unix Graphics Utilities Linux Multimedia Page Some of the Mailing Lists and Newsgroups I keep an eye on and where I get much of the information in this column: The Gimp User and Gimp Developer Mailing Lists. |
 |
Our company network is based on some sparcs and linux servers and windows (3.11 and 95) clients, wich telnet to the server to use a Cobol-written accounting program. After passing from nfs to samba (imagine the user's fun when they first discovered winpopup), we decided to try some fax software. We had some alternatives: comercial (and really expensive) Un*x software, the NT alternative, and the free software solution.
NT was an unfriendly and unflexible solution, based on licenses per user, and we didn't want to spend thousands of dollars buying an unix fax server. Having had the good samba experience, we decided to give hylafax a try.
HylaFax (originally flexfax) is made by Silicon Graphics, and distributed with source code, availiable at http://www.vix.com/hylafax/. Latest version is 4.0pl1. Get also the tiff library. If you get the source, you must first compile and install the tiff library (in order to convert tiff files to .g3 fax format). You must also have Ghostscript up and running to convert from Postscript to g3. As experience: use the latest ghostscript you can get (unless you would like to see your customer receiving ghostscript error messages by fax).
After having the tiff library installed, hylfax compiles at first under an stardard linux distribution, placing binaries under /usr/local, and /var/spool/fax for the jobs.
Once installed, configure the system by running /usr/local/sbin/faxsetup. It will add the fax user, modify /etc/services and /etc/inetd.conf (hylafax listens to ports 4559 and 444). After some other confguration, faxsetup will run faxaddmodem, in order to configure wich modem(s) to use. Faxaddmodem will talk to the modems you've specified, getting its parameters, and let you configure other stuff.
Hylafax consists in two daemons: hfaxd (the server), and hfaxq (the priorityzed Round-Robin scheduler). You should run faxmodem to tell the scheduler wich modem(s) it can use. If you've also planed to receive calls, you'll have to set up faxgetty, that will place incoming faximiles into /var/spool/fax/incoming, respecting also data calls (pasing the control to getty/mgetty). You should also add these daemons in /etc/rc.d. Now you can check the server works by telneting yourself at port 4559.
Some useful programs you will use are sendfax (files), faxstat (to check the queue), and faxrm to remove jobs. Sendfax calls faxq, sendpage, etc.. It also invoques ghostscript for the image format translation, so you'll normally send postscript or ascii text. If you want to send other formats, check out /usr/local/lib/fax/typerules. Other interesting configuration files reside at /var/spool/fax/etc: If you run in trouble with your modem, you'll probably want to check them.
And to finish with the server side, it's not a bad idea to modify crontab to invoque faxqclean, in order to remove sent faxes.
Once you've hylafax up and running, it's time to configure the clients: There's MacFlex for Macintosh users, and WinFlex for Windows users. With Winflex (and MacFlex too), you'll install a generic postscript printer (I usually use a Apple Laserwriter Pro600 window's driver). So, when something is sent to that printer, a window appears, asking for the phone number. You can also check the queue, remove jobs, etc. Once the fax is sent, the user will receive an e-mail confirming the job has been done with some other useful information. HylaFax creators claim that "you'll never loose a fax", and I must say that this aspect has been taken with a great effort.
WinFlex, although a good solution, is not perfect (the interface with the printer driver is a bit poor), and doesn't use all hylafax features yet (any volunteer?).
Another feature yet to be perfectioned, this time a server feature, is the automatic cover page generation: I've really had pains to create the cover page, much postscript knowledge needed. In our company, we finally wrote the cover page as a normal document with our word processor, and copy it in a samba share.
The real party began when I was told about the accounting department special need. They needed to send the facturation automatically by fax. That facturation was generated by the cobol program as an ascii file, up to 20 pages. But ALL pages had to inlcude the company logo at top, and some text at the left side. That seemed to be a harder issue than the cover page one, but after some scripting and some C, and thanks giving to hylafax flexibility, I could write a printer filter that:
Now, I don't even want to think how I'd solve this problem with a Windows server.
HylaFax is a versatile, powerful and flexible fax software, although missing some features. It's highly configurable, provides a good amount of debugging information, its secure, and it's free.
There's also a mailing list, where you can get patches and solve some problems. Once again, free software has proven me its strength.
You might have the feeling that Linux is a real good OS.
In this article I will pit some of Linux' features against those of some competing *nix's, and thus identify some of Linux's relative strengths and weaknesses.
Linux and it's competitors
Not so long ago a frequent Linux question was "Is it really useful or is it just another geeks only OS". Now most insightful people consider Linux as being on par with the best, and the interesting question is "when is it best to use Linux and when should some other *nix be preferred".
To help people identify Linux' place in the market, I've made a comparison of ten different OS's eight of them *nix's, where each OS's capabilities in a number of specific areas, are pitted against each other.
The comparison is available as an interactive chart at: http://www.falconweb.com/~linuxrx/WS_Linux/OS_comparison.html .
It's part of a bigger Linux-page called "The Linux Resource Exchange" that holds a lot of other Linux-info such as a searchable HOWTO-mirror, guides to both unofficial and official patches to the 2.0.* and 2.1.* kernels, Linux on workstation hardware pointers, and much more. Take a look at it at http://www.falconweb.com/~linuxrx .
It will be noted that the emphasis of the Comparison Chart as well as this article is on usability and suitability for "real-world-usage" rather than the more technically features of the kernels.
In this article I will present a summary of the information for Linux 2.0, Solaris 2.6, SGI Irix 6.2/6.4 and Digital Unix 4.0 and discuss it. The web-site has more info, and holds information for BSDI 3.0, Freebsd 2.2, MacOS 8, OS/2 4, UnixWare 2.1 and OpenServer 5.0 as well. While this article is fixed in time, I intent to keep the web-site up-to-date in a long time from now.
A small extract of the OS Comparison Chart
| Linux 2.0 | SGI Irix 6.2/6.4 | SUN Solaris 2.6 | DIGITAL Unix 4.0 | |
| OS interoperability | ||||
| Runnable foreign binaries | DOS, Windows 3.1, Macintosh, some SysV | Dos and Windows 3.1 | Macintosh, Windows 3.1 | |
| Mountable foreign filesystems | FAT, VFAT, UFS ro, SysV, HPFS ro, MAC | MAC, FAT | ||
| Java | yes | yes | yes | yes |
| OS-standards | ||||
| Posix.1 | Designed to comply, but only a hacked version has been certified. | yes | yes | yes |
| XPG4 base 95 | no | yes | yes | yes |
| Unix 95 | no | no | yes | yes |
| Unix 98 | no | no | no | no |
| Policy-issues | ||||
| Pricing | Free | Pay per release | Pay per release or 2 year subscriptions | Pay per release |
Linux and the OS standards
The days of the great Unix wars are sort of gone. It has always been part of the Unix-philosophy that a program written for Unix should not need anything more than a recompile to work on any vendors *nix. In reality there have always been many minor and major differences, making the task of writing applications runnable on a vide selection of *nix'n a challenging one.
During the 90' the vendors have agreed to write down and follow a set of common standards for *nix behavior. The first one to gain big following was the Posix.1 standard. In the last couple of years this standard have been enchanged by standards such as Unix 95 and Unix98, the newer standards including up-to-date versions of the older standards as well as standardizing additional areas of Unix. It seems that after a quarter of a century Unix can finally live up to the "Unix-box" metaphor, e.g. a generic square box with some flavor of *nix capable of running every random Unix-program you care to use.
It's as if OS's are becoming less important from now on. People want a box with 100 % standard Unix behavor so they can run all ther applications, and buy equipment and OS from whichever vendor has the best offer at the day of purchase.
The versions of *nix made before Linux consisted of many niveaus of revorkings of code that stemmed back from the earliest versions. This was necessary in order for a *nix version to behave to applications like it's counterparts so applications could run everywhere.
When Linus turned his Linux-development into a quest for a complete OS, the Posix.1 standard was his guideline. Having the OS <-> application interface ready, allowed him and the other developers to build all the internal parts of the OS without using any old code. Ideas fostered and experience gained since the original Unix could be freely used in the development of Linux, since none of the code from older *nix's had to be used.
This is one of the main factors that allowed Linux to be so much better than the competition. All the innards are brand new modern OS code, taking full advantage of modern hardware.
As can be seen in the chart above, Linux haven't got the official "I am Posix.1 compliant" stamp. A German company named Unifix has hacked on Linux and gotten their versions of both 1.2 and 2.0 certified. Their work have more or less been included in the main Linux-code. This doesn't make Linux Posix.1 certified, but it ensures that it's very close, probably as close as it's certified counterparts non-certified patchlevels and minor releases.
It's important that work is done to keep Linux in sync with recent standards, or it will turn into a non-standard *nix only suited for certain niche purposes, like we are currently seing various BSD derived *nix's do.
Linux does only have a cost of zero if your time is worthless
The fact that Linux' price tag says zero is not as interesting as it might seem.
Most of the cost of owning and using a computersystem, is the cost of time spent on learning how to use the system, time spent on installation and maintaining it over it's lifetime, and the initial cost of purchase of computer, applications and OS.
If Linux is a cheap OS then it's because it can do more with less hardware than many of it's competitors, or because it comes preinstalled with many hundreds of apps., saving installation time, or since it gives it's users the ability to work smarter, rather than by the OS itself being obtainable without expense
Linux has better documentation than most OS's, and all of it is on-line, so it keeps itself current and is search-able, unlike shelves full of expensive vendor supplied paper manuals. The newsgroups and mailing-lists provide a rapid help and support forum, that beats every phone-support system I have ever used. This ensures more rapid problem fixing than most other OS's even when the local gurus are out of luck, and can be used as a learning tool, thus helping all Linux users work smarter than people using some other *nix.
Linux can make a PC do most of the tricks an ordinary workstation-user makes his workstation do. A workgroup with workstations can be renewed to a few high-end workstations as shared CPU servers and a Linux PC on every table. This costs less, and the really speedy CPU servers ensures that the users gets more power than before.
What makes Linux an economically OS isn't so much it's own cost of zero, but all the related savings and improvements it gives it's users.
Linux speaks many tongues
One of the first business support purposes Linux was widely put to was to act as a multipurpose network device and server. It's capable of handling most of the purposes needed to keep a modern LAN or WAN running. It can be both router, firewall, bridge, gateway, modem and ISDN dial-up server, nameserver and many other network task imaginable. It's also really good at server jobs like mail, ftp and web.
Having the same OS with the same tools doing all these very different jobs, instead of having to use a different device for every task, is saving people a lot of time, gives more flexibility, and ties up a lot less money in equipment purchases or leases.
Other *nix'n have somewhat similar abilities, but most require expensive workstations and really expensive network peripherals, and those that does run on PC's doesn't support an equally huge amount of cheap peripherals and software as does Linux.
I am writing in response to Dave Blondell's letter, where he says "The sad truth of the matter is that Bently, and for that matter most other software companies don't get enough requests for Linux ports to justify the production costs."
Well perhaps it's true for ports from non-Unix environments, but it surely is not true otherwise. A look at page 84 "Linux Makes The Big Leagues" and "A place for Linux" is exactly the how I persuaded our company to start using Linux. For only $250 we could have Linux with Metrolink Motif, what's more we could use a cheap PC clone that put our HP715 to shame in the performance stakes.
As we started to use Linux seriously, we bought more tools like Insure++, CodeWizard, and INT Edittable Widgets. Soon the HP was gathering dust, and only used for porting to HP-UX and testing. Ironically the HP715 has just been paid off this year, its still a nice machine, but its no match for a high end Linux PC.
Since we associate closely with some of our clients, they often visit and get to see some of the new enhancements that are under development. Often they noticed how fast Linux was compared to other platforms, so natural evolution took place, and a lot of our clients have switched to Linux.
And the best part of all is that I never need to change a line of code when compiling across platforms, I use simple shell scripts that are used as CC and LN. An example would be..
------------------------------------- mcc --------------------------------
#! /bin/sh
name=`uname -m`
if [ $name = "i386" ]
then
cc -DSCO $*
elif [ $name = "i486" ] || [ $name = "i586" ] || [ $name = "i686" ]
then
cc -O2 -m486 -fomit-frame-pointer -malign-loops=2 -malign-jumps=2 \
-malign-functions=2 -DLinux $*
else
c89 +w2 -z +FPD -DHPUX -D_HPUX_SOURCE -I/usr/include/X11R5 \
-I/usr/include/Motif1.2 -I/mnt/INT -I/mnt/700_LIBS/xpm-3.4e $*
fi
--------------------------------------------------------------------------
The combination of Linux[Intel] with its LITTLE ENDIAN architecture and HP-PA Risc with its nice BIG ENDIAN (Same as networking) provides a really nice combination of test beds to ensure both byte swapping and 64/32 bit compatibility is tested.
At the end of the day it is no extra effort to provide a Linux solution. Probably the biggest deterrent is the _loud_ anti-commercial voices. Some folk who don't mind paying for software should be more vocal.
Recently a really nice guy called Jay, explained to me why the GNU philosophy was so good, he said someone pays you once to do the work then the rest of the community should be able to get the benefit of your work for free, as you have already been paid.
When I pointed out that most commercial applications take many man years to write, so we have two options, to get one poor soul to pay millions of $'s or we can try to market our product to ten thousand people who would each only pay $100 I got no response.
And while not every one may appreciate or use any of the free software that I have contributed to the Linux community, some of the credit must go to my employer (Who does not provide free software as a rule) for the skills and resources I used to create my free S/W were gained from them, in return they use some of my free S/W.
Many Linux users tend to think of Windows95 as a competitor to Linux. In mailing lists and in Usenet it is common to encounter comments that portray Windows95 as the materialization of evil and Linux as the savior of all cybernetic souls. While it is my belief that only a small portion of the Linux community believes the source of all darkness is Redmond, it is easy to get caught by passion and forget to analyze this situation through a more technical light, which would definitely be more productive in promoting the growth of Linux, through it's own merits.
Of course Microsoft has thrown more than it's share of low blows over the years. But it is hard for me to believe that any other company in the position Microsoft was in would act much differently. And in any case, the Linux community has nothing to gain by confronting the Goliaths of the software business in any field except the technical one. The media attention we have received lately is totally funded on the quality of Linux, which by the way separates us clearly from the pack. This attention will only grow in the future, especially if we present ourselves as mature albeit idealistic developers, which most of us are.
We know all too well that Windows95 and it's applications are not as stable as we would like, that support is very poor and expensive, how inflexible and insecure it is, and all the other perils that plague it. People in charge of supporting it are familiar with error messages like: "Consult an Expert" and "Reinstall Windows95".
But if you can put up with that, what you have is an extraordinary operating system: It is very easy to use, install and configure; It is inexpensive; It has impressive internationalization support; it has excellent development tools; it is supported by nearly every major hardware manufacturer; not to mention the tremendous amount of high quality software available in almost every category for the platform.
Linux, on the other hand, has a different set of advantages. It is rock solid, has excellent support, is extremely flexible and secure, is free, is open, and so on. From a technical point of view, it is incomparably superior to Windows95.
The problem is that companies have invested billions of dollars in software and training for the Windows platform. And Linux does not run Powerpoint, or MS Word, or Delphi. Also, most end users will not take advantage of the extra flexibility and security offered by Linux. It is not that they have no use for it, it is just that they are so used to working with what they have, and so wary of changes, that they don't really care about the advantages they may get. It is sad, but true: They would rather not save sensitive information than learn about permissions; They are so used to rebooting their machine all the time that it has become as frivolous as clicking a mouse button.
Most end-users spend the whole day performing parametric transactions on their machines. In many cases, even management will prefer to wait days or weeks for their IS department to prepare a GUI interface to a query than to learn SQL and get the information immediately. Of course I and many people use Linux for most of my personal computing needs. When I use Windows95, I really miss the things we take for granted in Linux, like powerful command line tools, permissions, stability, etc... But unfortunately most users are not like that nor are they likely to be.
Linux is best exactly where Windows is lacking. It is strong in support for different software platforms. It is designed to be sturdy and take heavy workloads day in day out. It has marvelous internet tools, and picks up the security buck where Windows passes it. Nobody wants a web server or for that matter any server in which you can't have 100% confidence on.
For all these reasons, looking at Linux as an alternative to Windows95 is in my opinion a mistake. It's greatest potential will be achieved as a server and manager for Windows, complementing Windows' weaknesses and guaranteeing a high level of service to the enterprises who select it. If at all possible, it's generally a good idea that end users don't even know<\#151>or need to know<\#151>that it's Linux that is offering the advanced services they're using.
That having been said, the natural competitors to Linux become Windows NT and other unices. So let's see why it is by far the natural choice for this role.
In every step of the initial cost equation you will be saving money with Linux. To begin with it is free, or almost free if you want to take into account the cost of a distribution. Then It requires far less computer resources than it's competitors, and you'll also save money there. Also it will often eliminate or reduce the need for additional equipment, especially when compared to NT. Then it is portable to several platforms. So instead of supporting NT, Solaris, Ultrix and AIX, each with it's own expenses in training, documentation, etc..., now you only have to support Linux. That aspect alone can save thousands of dollars every month to an organization.
With regard to software, not only you will find almost every type of software you may need for free or very inexpensively, but bugs are corrected and new features are added with incredible agility. No more of that "it will be fixed in the next release" talk. And since almost everything comes with source code, if your organization needs a feature with great urgency, it is much easier to add it than with a closed box OS. That is not to mention the speed with which Linux itself is updated. Security holes and bugs are quickly tracked and fixed, frequently in a matter of hours. Nobody can put a price tag on that.
Probably the biggest difference between Linux and it's competitors is in support and documentation. No, it is not commonplace yet to have your Linux vendor put you on hold for half an hour to charge you big bucks for online support like the other guys. And yes, there are situations in which online support is indispensable. But there are already options for online support for Linux, a business which has everything to grow considerably as Linux invades the corporate market. And in an emergency, putting a Linux server up and running can be done much faster than any of it's competitors. In fact, in many cases you can have a spare hard disk laying around for an eventuality. If you need it, pop open just about any PC, stick the disk in there, turn the machine on and go. Also, if you want to really do things right, the low setup and maintenance cost makes redundant solutions using Linux much more interesting than with any other OS. And that is not to mention that a lot of people, including probably the people who will be in charge of maintaining Linux at work, use or will use Linux at home. How many people you know use Ultrix or even NT at home?
If your business is connected to the internet, you will get an infinite knowledge base, always willing to help, generally for free. Antagonists will say: "Other OSs have their own mailing lists and Usenet groups too." But the fact is that no other internet support group is even closely as effective as Linux's. Linux is unique in that it offers many more tools to fix your problems. It doesn't matter how big a guru you may be, if the software you use is not traceable by a debugger and doesn't come with source, you will not be able to get answers as fast and as easily. And there is a "positive spiral", as Bill Gates would like to define it, with Linux support: A lot of people learned a lot of what they know through the Linux internet support channels. Now they feel in many ways obliged to help lots of other people. Who will learn a lot of what they will now through these channels. And so on.
Linux documentation is incomparable to any other OS's. Not only in quantity, quality and price, but also in that it is so frequently updated. From novice users to accomplished network administrators, it is more than likely that you will find most of the answers you need from the documentation that comes with your distribution or with the CDs that accompany it. If you don't find it there, it is almost always somewhere in the internet, reachable by any search engine. More and more books are published every month about Linux. There are monthly publications like Linux Journal and Linux Gazette available. There are tutorials, howtos, faqs and other documents describing every single detail of the operating system, and most of the software that comes with it. And that is not to mention the inheritance of over 20 years of UNIX expertise and information. In total, the amount saved with support and documentation expenses every day with Linux can add up considerably.
Administrative costs are also much lower in Linux, and administration is much easier on Linux than in any other OS. An argument many people use in favor of NT is that it is so easy to administrate. A lot of UNIX people were at first fearful of losing their jobs when NT came out. Now, how many NT sites you know don't have a dedicated administrator? The fallacy of Microsoft's argumentation is that administrative costs are not affected by creating new users in a GUI instead of using a shell script, or even editing a file. They are not affected by day to day operations when things go right, and they are not affected by performing ordinary maintenance. What really skyrockets your administrative costs is when things go wrong. And anyone supporting networks knows that they do. With any system. And when that happens, you need clear error messages. You need trace and debug capabilities. And you need documentation. And Linux offers all these items in great generosity, much more than NT and more than most other unices.
Another factor that increases your administration costs is when you have to do anything that is out of the ordinary. When that happens, you want flexibility. And while NT may be acceptable for cooking pasta, finer dishes will require tools and flexibility you can only get from UNIX. Because Linux is so flexible, you can frequently eliminate routers, bridges, and other equipment which not only add to additional hardware cost, but also contribute to make your network more complex, introduce new environments to be learned, and become yet another failure point. With Linux, cost involved in the maintenance of these equipments can often be eliminated, and other times, greatly reduced. @subhd:Getting To the Point<\#151>Integrating Linux and Windows95
Using Linux with Windows95 is not a very complicated task. Most of the work is handled by the Samba suite, a host of programs designed to work with the SMB protocol, capable of most services you expect from a network server: Handling logins, sharing hard drives, printers, etc... Samba is especially useful when you have a mixed UNIX/Windows95 environment, like we did at the Mathematics Department at UFC. When people logged on any Windows machine, they would have access to their home directories at the H: drive. This brought up an administrative problem, as people quickly took up all the hard drive space available installing Windows programs in their H: drives. Nothing that a quota system won't fix.
Samba fools your Windows95 machine into thinking that it is talking to a NT server. You can have network profiles, unified registries for all your machines, run login scripts, and generally have most of the bells and whistles available with NT. [See earlier issue of Linux Journal]. It is one of the best supported and documented programs available. The only problem I had is that logins take a little longer to complete, when compared to NT. It is generally a little slower than NT, but perfectly usable. The configuration files have a format similar to the Windows .ini files. You can use it to share printers, hard disks, cdroms, etc... According to the documentation, there is no real reason why other mass storage peripherals shouldn't work, although I haven't tried any.
At PCC Inform=E1tica, a computer retailer at which I installed an intranet based on a sole Linux server, I also installed HylaFax, an excellent fax server. It was not as simple to install, mainly because it asks so many questions that it can scare you. If you take your time to answer them, especially with the aid of your Modem's manual, it should be no big deal. Also it searches for some programs which you will not find in most distributions. For instance, it asked me for mawk, which I symbolically linked to gawk, and never had any problems. The Windows95 Hylafax client, whfc, works reasonably well, although it is not quite stable enough for everyday use, and lacks important features, like job scheduling. I contacted the author, but he was busy with other projects, and told me that he could not release the source code because of limitations by his employer. HylaFax is so richly documented I decided to implement my own client, with the specific needs of my organization. As soon as I get a couple of machines, I will start doing that. Any volunteers?
Mail came mostly configured. Not only sendmail was configured correctly almost right out of the box, but a pop server also already came installed. All I had to do in Windows95 was install a major browser.
Information about products is created on regular Windows95 programs, then converted to HTML and made available for the intranet at the Linux server. Tutorials and documentation for installed programs available in HTML are also available from the server.
The Linux machine at PCC Inform=E1tica also has the responsibility of doing IP Masquerading for the whole network of 22 machines and counting. I had to get the newest stable kernel at the time (2.0.29), and a patch for it to work with ftp.. Even in this kernel, the help message on the configure script will say that masquerading is experimental code. I never had any problems, running the machine under the conditions above. Once the kernel was recompiled, all I had to do was add two calls to ipfwadm and I was all set. I had invaluable help from the people in the internet for this task. The Brazilian linux mailing list linux-br, an Issue of Linux Journal, the kernel documentation, web documentation, were all useful tools for me to get this job done.
Telecommunications in Brazil is very expensive. At the time we were planning this network, our first thought was on getting a 64k leased line from the company to our service provider. That would cost us around US$1050 a month, only on telephone company charges. So we decided to build a new machine, install it at our service provider and put in it our web content, ftp server and mail server. The company would then access the internet via a dial-up account, which would cost us only US$210 a month. Since dial-up calls tend to fail a lot, I made a simple script which would check if the line was ok, calling the service provider again in case the line had dropped. Also this script mailed my outside account the current IP number for the machine, in case I needed to access it from somewhere else in the internet. Then I put the script to run every 5 minutes with crontab. Simple and agile. In other words, low administration costs. If the bandwidth required increased sufficiently, it would be easy to add a second modem and use equal line balancing to get a higher throughput.
Another use for crontab is making automatic backups of the companies database, which runs on Access. Everyday at noon and at 6PM a copy of the whole database is made to the server using a script based on smbtar, part of the Samba suite, and at 8PM a copy of the database is made to tape. The home directories, which users use at their Windows95 clients mainly to store business proposals, are also saved to tape every week. Most users don't even know there is a Linux machine in the network. @subhd:Bottom Line<\#151>Savings
Savings with Linux start with the O.S. itself, grow through setup with lower power equipment (All the above work smoothly on a Pentium 133), and by making networking hardware dispensable (router), goes through easy software setup, flexible settings and easy administration and training, and adds up every month, with low equipment maintenance costs, agile software updates, and inexpensive support. It also protects your investment by allowing you to easily upgrade to other platforms. Or even other OSs, if you for some strange reason would ever want to do that.
How much you will actually save depends on many factors, but there are just so many ways to save with Linux, from support fees to documentation to feasible redundancy which means less down time to flexibility that one thing is for certain: It will be a bundle. At PCC, Linux saved more than US$3000 in initial setup costs and another US$1000 every month, out of software, communications and maintenance costs. It also has increased the safety of the data on the network, provided the employees with the convenience of private disk space and access to the wealth of information offered by the internet and made internal communications more agile and inexpensive. If you though your company or office was too small to afford a high quality intranet or a company-wide internet connection, think again. With Linux, Now You Can!!!
The GNU gcc compiler is one of the most highly-regarded applications made available by the Free Software Foundation; it has become an integral part of Linux distributions. The existence of gcc and its corollary utilities (make, autoconf, etc.) makes it possible to distribute source code for everything from the Linux kernel itself to a wide variety of free software applications and utilities. This fact is crucial to the survival and health of Linux; different people run different kernels and distributions, and it would be expecting too much to ask volunteer developers to create binary distributions for all of the different flavors and variations of Linux and other Unix-derived operating systems. Richard Stallman does have a valid point when he emphasizes Linux's dependence upon the many GNU utilities.
Lately there has been a flurry of activity in the GNU gcc compiler world, resulting in new releases and giving Linux users expanded choices in their development environments.
The GNU people operate in a relatively closed environment; the average user doesn't have access to news or progress reports; a new release is usually the first indication that development is actually progressing. Since GNU software is released under the GNU licence, there is nothing to stop other developers from modifying the code and making available variant releases. There exists another approach to free software development, in which patches and "snapshot" releases are freely available for interested developers and users. The Linux kernel (with both stable and unstable development releases available) is an obvious and influential example. XEmacs, KDE, and GNOME are others. Since the advent of egcs it seems the GNU developers might be moving toward this development model, judging by some new material at the GNU web-site. Eric Raymonds' online article, The Cathedral and the Bazaar is an insightful and interesting interpretation of these two different models of free software development. This piece was one of the inspirations for the first gcc variant (that I know of) to become available: egcs.
Gcc 2.7.2 has been the standard GNU compiler for some time now. The Cygnus Corporation is a company which offers commercial support for the GNU utilities and has ported many of them to the Windows environment. A group of programmers there decided to try an experiment. Beginning with the stock GNU sources, they adapted the patches which would eventually become gcc-2.8.0 (I assume from the GNU gcc development source tree) and added experimental features which the GNU developers either weren't interested in or were delaying for a future release. The idea was to make periodic snapshot releases freely available with the hope of attracting more developers. This approach seems to be working; I don't know how many new programmers are contributing to the project, but the two releases they have made to date (1.00 and 1.01) are being used by quite a few people without many problems. Any fruitful changes in gcc/egcs will be available to the GNU gcc developers for possible inclusion in future releases. This benefits end-users as well as the GNU programmers, as users get to try these new features and functions (and hopefully bugs will be reported and dealt with), while the sources may be of use to the GNU gcc people in their efforts.
Both the gcc and egcs compilers are intended to be built and used on systems based on a variety of processors. Yet another group of developers has hacked the egcs code to support operations peculiar to the Intel Pentium processors. Pgcc consists of a set of patches which can be applied to the egcs source, which will allow code to be compiled with various pentium optimizations. These developers claim execution speed (of binaries compiled with pgcc) can be five to thirty percent faster than stock gcc. A new Linux distribution called Stampede is using pgcs to compile the binaries of the kernel and applications which they plan to distribute. Interestingly enough, the original patches which the pgcc team used as a starting point came from a programming team at Intel.
Though the GNU gcc compiler has always worked well for me, the appeal of novelty led me to tentatively experiment with egcs when the first real release appeared on the egcs web-site late last year. The first thing I noticed was that the compiler tends to generate more warnings than the -Wall switch did with gcc 2.7.2. These don't seem to have deleterious effects, and I've heard gcc 2.8.0 exhibits the same tendency. Everything I tried seemed to compile successfully except for the KDE source; I've been told that this will be fixed for KDE beta 3. If you've never built a version of gcc from source be prepared for a long, disk-space-intensive compilation. It happens in several stages; during the last of these the compiler actually compiles itself, a process known as boot-strapping.
Some time after installing egcs I happened upon the pgcc web-site. I downloaded a large set of patches and patched the egcs source, ending up with another compiler. Along with the claimed execution speed increase (which in most cases probably isn't large enough to be noticeable) optimization can be increased to -O6, and a pentium-specific flag (-mpentium) can be used. The binaries generated tend to be substantially larger than gcc's due to the default inclusion of exception-handling. This can be disabled with the switch -fno-exceptions.
So far I've compiled several Linux kernels, XEmacs, mutt, slrn, the Gimp, gzip, bzip2, and others without any problems. I wish I was a systematic type of person and had timed the execution of these programs before and after using egcs/pgcc, but I'm not. As an example, I'm running XEmacs 20.5 beta-22 using the Linux kernel 2.1.84, and the editor seems snappier and more responsive than before. But is this due to the compiler, the kernel, the XEmacs version, or (most probably) all three? Too many variables and not enough time!
I wouldn't recommend installing any of these gcc variants unless you are willing to monitor newsgroups, web-sites, and possibly the mailing-lists. Luckily problems and work-arounds are reported quickly, and of course the invaluable safety-net of gcc distribution packages is always there if your set-up gets badly hosed. It will be interesting to see what comes of this non-adversarial fork in the evolution of gcc.
Last modified: Sat 31 Jan 1998
Linux may not have many office-suites available, but it sure does have a wide variety of system, process, and memory monitors! I use ProcMeter quite a bit, mainly for the incoming and outgoing TCPIP packet display, but recently I happened upon an unusual memory monitor which displays the relative proportions of memory in use by running processes. Gmemusage is a small X application written by Raju Mathur. He has been attempting to emulate a monitor (also called gmemusage) which is used on Silicon Graphics workstations.
Here is a screenshot, which will save me several paragraphs of description:
As with many other such monitors, the information shown is essentially the same as what is shown in the memory fields produced by ps -aux, which derives its information from pseudo-files in the /proc directory. These files, such as meminfo and loadavg, are generated dynamically by the kernel. You can read them directly, by running a command such as cat /proc/meminfo.
Although a plethora of information is presented by the output of ps -aux or top, more detail is shown than is needed for a quick overview and comparison, and tabular data doesn't easily lend itself to comparative analysis. You won't see precise differences between memory usage while contemplating a gmemusage display, but the proportions are shown in a graphical and easily interpreted format. In most cases the relative proportions are more useful than the decimally exact detail shown by ps or top.
Raju Mathur has plans to enhance gmemusage. One possibility (mentioned in his TODO file) is to add a pop-up window which would give additional information about a process when its name in the main display is selected with the mouse.
I like this small utility, partly because it diverges from the usual dynamic bar-chart display found in many memory monitors, and also because it is small and specialized. You don't have to spend time configuring it either; it works well "out of the box". If you would like to try it, the source archive is available at the gmemusage home WWW site. Last modified: Sat 31 Jan 1998
ephemeris n., pl. ephemerides 1. A table giving the coordinates of one or a number of celestial bodies at a number of specific times during a given period. 2. A publication that presents a collection of such tables; an astronomical almanac.
The above definition came to mind when, some time ago, I happened upon a Debian package called xephem while browsing the contents of a distribution CD. At the time I dismissed any thought of installing it; I could visualize (falsely, as I later learned) a simple X application displaying scrollable lists of sun, moon, and planet rising and setting times for various latitudes. This sort of information is easily available from printed ephemerides and hardly justified installing a probably old package.
A salient aspect of free software is that it's not advertised, and word-of-mouth has its limitations. News of an application with wide appeal, such as an editor or file-manager, will eventually be spread via the internet, but a program which occupies a specialized niche might not receive the attention it deserves.
Some time later I saw a brief description of xephem in a usenet posting which was enough to spark my curiosity. After trying it out, I was impressed, and thought the word should be spread.
Xephem is a Motif-based X application which goes far beyond the name's implication. It's a multi-purpose astronomical program which can present detailed, zoom-able star-charts as well as views of the earth, moon, planets and the entire solar-system. These views can be from any location on Earth, at any time in the past or future.
This application can be effective on several levels. The casual star-gazer can consult xephem just to see what planets and constellations are visible on a certain night, and perhaps print out a star-chart. As a teaching aid xephem's graphical and animated displays could spark a student's interest. The serious amateur astronomer can set up a link between a telescope and the program, so that the sky-view displays whichever spot the telescope is also seeing.
This review will be more comprehensible if a screenshot is presented first. The first window which appears when xephem is started is the control window:
In this window various parameters, such as location, date, and time, can be set. From the menubar the view windows can be summoned, as well as which of the various astronomical databases (included in the distribution) should be loaded into memory. These databases are quite a useful resource to have available. They include the Messier and NGC databases of deep-sky objects, along with databases of asteroids, comets, and satellites. Updated versions of the latter two are available on the xephem web-pages.
Here is a screenshot of a skyview window:
This window is much more than a simple star-chart of a certain date, time, and location. Right-mouse-button clicking on a star or other astronomical object summons a small window showing various facts about the object. Zooming in can also be done with the mouse, and a zoomed view can be panned using the scroll-bars. A variety of viewing options can be set from the menubar. The constellation names and outlines can be shown, and if any of the xephem databases are loaded the objects in them will be visible, if desired.
One view window which I find particulary interesting is the earth view. A representation of the earth from an orbital viewpoint is shown, with the sun's illumination and current zenith-point highlighted. This is updated in real-time, and equivalent views displaying the zenith location and area illumination of either the moon or the other planets are menu options.
Another view-window displays the solar-system in schematic form. This and the earth-view windows can be animated, a sort of cartoon-movie which shows the relative movements of the various celestial objects.
Those of us that have used Netscape (or other Web browsers) under Windows, may have felt some envy at the sight of the Dialer, a little box in one corner of the screen showing that you are on-line and how much time you have already spent on-line, so your phone bill doesn't go overboard.
In Linux, on the other hand, setting up a dial-up connection and making it work is often a rather painful process, a "challenge", if you like: Not only no handy auto-install packages available from your internet service provider -- you have to figure out everything for yourself, and know what questions to ask -- but also establishing the connection every time requires you to go through a sequence of operations.
Open an xterm or a virtual console, log in as root, and run the ppp startup script (unless of course you use the diald package for dial-on-demand, an alterative also. I personally found that it had too much a mind of its own :-).
Closing the connection similarly requires you to do the same to run a disconnect script.
One of the first things I did therefore when I decided to learn tcl/tk was to write a Dialer look-alike. It (tkdial) is attached to this text; it is the first tcl/tk program I ever wrote -- just under 150 lines -- and that may show. But tcl/tk is ideal for this kind of job, "glueing" existing command line facilities together into a beautiful motif-look, mouseable package. Just have a look at the pictures!
![[link down]](./gx/vermeer/linkdown.jpg)
![[link up]](./gx/vermeer/linkup.jpg)
There are some things with a dial-up connection which appear not generally known (I'm not talking to you, geeks and gurus :-). I'll give a quick run-down of my experiences as I understood them (but note that I am no professional):
Acknowledgement: I am indebted to Jaakko Hyvätti of EUnet Finland, who provided me with working ppp scripts and plenty good advice.
![[my desktop]](./gx/vermeer/mydesktop.jpeg)
Linux is the perfect operating system to deploy in a hostile environment, the built in security features combined with the customization most window managers allow make Linux ideally suited to this task. Recently a local career planning agency wanted to deploy a dozen public access Internet workstations at various locations in the community including libraries and hospitals. Linux was chosen as the operating system for the task. This article provides details about how to setup Linux so that it can safely be deployed as a public access workstation.
When it came time to decide on how to setup the workstations various solutions were considered. It was decided before hand that the hardware would be Intel-based PC's. That essentially left us to consider the various Microsoft offerings or Unix. The licensing costs for NT would have added significantly to the projects budget. Even after buying NT licenses for each workstation, an experienced administrator would have had to spend time configuring and securing each NT machine. It was determined that NT was an option, but an expensive one. Win95 is significantly cheaper than NT, but lacks the built in security features of a more advanced operating system. Our biggest fear with Win95, was that we would frequently have people walking in and messing up the systems setup. Linux offered us a solution to all of these problems. The flexibility of X-Windows, combined with Linux's basic security features allowed us to setup the workstations such that we did not have to fear hostile users. The licensing costs were essentially non-existent, and setting up each workstation became a manner of following a simple routine.
When you have to setup a bunch of Linux workstations with essentially the same configuration, there are two approaches you can take. The first one consists of setting up and testing the first machine, then dupilicate the entire hard disk onto each workstation. (If you are doing this remember that you will most likely have to re-run Lilo on each workstation). The second method is to manually set-up each workstation by following a standard check-list. We opted for the second method due to logistical reasons. However, the installation procedure was automated by re-using config files, and running scripts where possible.
We used RedHat 4.3 as our distribution, installing from the RedHat PowerCD set. I suspect any decent Linux distribution would have worked equally as well. By the time we had finished the installation of the first machine, I had established a step by step checklist of things to do during the install. As we went along, we occasionally revised the check-lists which required us to go back to the original few machines and make some changes after the fact.
The installation started out as a standard Red-Hat install, the machines had plenty of hard disk space so we were quite liberal in what packages we installed. This included any networking stuff we felt was relevant, and X-windows. We had to manually install
ipfwadm since there wasn't an explicit option for it.
The XF86Config file is the configuration file for the XFree86 X server. We created this file as we would have for a normal Linux workstation running X except added the lines "DontZap" and "DontZoom". DontZap prevents a user from killing the X-server with a break key sequence. DontZoom prevents dynamic changing of resolutions. Both of these options prevent a hostile user from making the machine look somehow different for the next person that comes along. Further details about this file can be found in the XF86Config man page.
The following files are located in xdm go in /usr/X11R6/lib/X11/xdm.
The XResources file controls settings for xdm's log in process. We used the standard XResource file but added/changed the following lines. They all effect the apperence of the login window, with the exception of the last line which allows our guest account to work without a password.
and removed the following from the translations section to a user from getting around XDM.xlogin*greeting: Welcome, please log in as 'guest', with no password.
xlogin*namePrompt: login:\xlogin*fail: Login incorrect, please use the username 'guest' with no password
xlogin*allowNullPasswd: true
Ctrl<Key>R: abort-display()\n\
We choose fvwm as our window manger as a matter of personnel preference and familiarity, most other window managers will require similar changes. All configuration information for a users fvwm setup is stored in a file named .fvwmrc located in their home directory. A system-default version of the config file is often located in /usr/X11R6/lib/X11/fvwm/system.fvwmrc. We will use this file as our base, and outline the important things you will have to check for. Since there is no "standard" base fvwm configuration, I will only outline the changes to make, and will assume familiarity with the format of an fvwmrc file.
The config file you use as your base will most likely start off with some pop-up menu's predefined. You will want to remove many of the predefined menu items.. I would recommend only leaving two items, "netscape" and "exit".
It is a good idea to disable paging, this will avoid some unnecessary user confusion.
This can be done with a line saying.
It is also a good idea to remove the "Pager" line if one exists.PagingDefault 0
The GoodStuff program that comes with Fvwm places a "Button-bar" at a predetermined location on the screen. This button bar allows for easy launching of applications. GoodStuff is a flexible program that can be tailored to your taste. I chose a button bar consisting of a single row located at the top-left of the desktop. The following are the relevant lines.
I created a pixmap file named netscape.xpm containing the netscape logo to be used as my icon. Pixmaps are usually stored in /usr/X11R6/include/pixmaps.*GoodStuffRows 1*GoodStuff Netscape netscape.xpm Exec "Netscape" /usr/local/netscape/netscape*GoodStuff Logout mini.exit.xpm Quit-Verify
Fvwm allows you to execute certain programs upon start-up. Since any guest users logging onto the machine would be using the Internet, we decided ensure that the modem starts to dial as soon as possible. We added an Initfunction section to the end of the fvwmrc file. If the PPP link already happens to be up, the ping will be successful, otherwise the kernel should start the connection process. Replace router.myisp.ca with the hostname of a machine located at your ISP.
Function "InitFunction" Exec "I" /bin/ping -c 1 router.myisp.ca & EndFunction
In a situation where the console is publicly accessible the BIOS is your first line of defense against hostile intent. Most modern BIOS's support password protection of some sort. It is recommended that a boot-up password be set. In our setup, we decided that we only wanted to allow "trusted" people to be able to boot the machine. Otherwise someone could boot the machine using a floppy disk as the root file system,(thus they will be able to gain root privledges), or alternatively boot into DOS and format the hard-disk. In addition to the boot-up password we also installed a password to protect the BIOS setup, and disabled booting from the floppy drive.
/etc/inittab is the configuration file for the "init" process. Since we wanted our workstations to work only in X-Windows, we changed the initial runlevel to 5. It is done with the following line. This means that when the machine boots, The X-server and Xdm are started automatically.
id:5:initdefault:
"Init" is also responsible for handling the "getty"'s or terminal monitors which handle text-based logins from the console or other terminals physically connected to the machine. The default inittab file should have a section that looks similar to this.
You should remove the "5" from the second section of each line. The result should look something like this.1:12345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6
This means that when the system is in runlevel 5(The runlevel where X-windows starts up to handle log-ins.) A user is unable to login from the text-based console. Before making this change it is a good idea to insure that X-windows and XDM are working properly. Disabling text-based logins is not essential to security, but we felt that it would confuse users who would walk up to a machine that was left logged in text mode. If for some reason X-windows stops working after you disable text-based logins, you will have to boot the machine into single user mode in order to login. This can be done by passing an option to the kernel from the lilo command prompt.1:1234:respawn:/sbin/mingetty tty1
2:234:respawn:/sbin/mingetty tty2
3:234:respawn:/sbin/mingetty tty3
RedHat uses the SVR4 style init-scripts to manage the boot-up process. The basic idea is that there is a directory for each runlevel under /etc/rc.d. When init switches runlevels it goes into the appropriate directory and executes each file that starts with a 'S' in ascending order. Eg on my RedHat system, when my system enters runlevel 3(multi-user) first /etc/rc.d/rc3.d/S10network is executed, and lastly /etc/rc.d/rc3.d/S99local is executed.
Even though we disabled the getty's for the console, a user could still press CTRL-ALT-F1 (or another function key) to switch to another virtual console from X-windows. I am unaware of a way of preventing this (short of kernel modifications). So in the event that a user accidently ended up switching virtual consoles we decided to leave the user instructions on how to get back into X-windows. We created the file S90Console and placed it in /etc/rc.d/rc5.d and gave root execute permissions to it. The file looks as follows.
Since getty does not run on any virtual-consoles, the X-server uses the second virtual console by default.#!/bin/shD="Press Ctrl+Alt+F2 to use this computer"
echo $D>/dev/tty1
echo $D>/dev/tty3
echo $D>/dev/tty4
echo $D>/dev/tty5
echo $D>/dev/tty6
echo $D>/dev/tty7
The file /etc/inetd.conf is the configuration file for the inetd daemon. This daemon is responsible for starting daemons that provide network services when needed. Not all daemons are started by inetd. Many, such as sendmail and httpd can either run in standalone mode, or under inetd. If your machine is only being used as a workstation, and is not providing network services to anyone then you should disable all unnecessary daemons. To disable a daemon that is currently being started by inetd, just added a '#' sign at the beginning of the relevant line to comment it out. I would recommend disabling finger, pop, ntalk, talk, and any other daemons that are not being used. We decided to leave telnet and ftp enabled to allow for remote administration. However if you are doing this remember to keep an eye out for security advisories that deal with problems associated with these packages(and any other program that is running on your system.) Usually fixing a bug is just a question of upgrading to the newest version of the program in question.
The Linux kernel can be configured to support IP Firewalling. This allows you to specify what packets the kernel should ignore, for example you can instruct the kernel to refuse to route any packets from the local machine destined to TCP port 25(of any machine). You must enable IP Firewalling, when compiling your kernel if you want to use this feature. You control the firewall parameters with the "ipfwadm" command, usually located in /sbin. We added the following lines to /etc/rc.d/rc5.d/S99local.
/sbin/ipfwadm -I -f
/sbin/ipfwadm -O -f
/sbin/ipfwadm -O -a deny -P tcp -D 0.0.0.0/0.0.0.0 25
/sbin/ipfwadm -O -a deny -P tcp -D 0.0.0.0/0.0.0.0 119
This restricts all outgoing traffic to port 25 (The mail port) so users can not send mail. Since anyone could walk up and use our workstations, we felt that it would be a bad idea to allow them to send mail. Likewise we restricted port 119(the news port) so usenet access is not allowed. Ideally we would have liked to allow read-only usenet access from Netscape, however I could not figure out how to do this so decided to be safe and restrict all usenet access.
In order to insure that your setup stays, you will want to change the permissions on various files located inside the guest users home directory. By this point you should have already created a guest user. You should also run netscape for the first time as the guest user before making these changes.
The commands above were executed, first we gave root ownership of the users home directory. Changing ownership prevents the user from changing the permissions back. Then we removed write access to the home directory. Next we changed ownership and removed write access to the .fvwmrc file, the .bash_profile, .Xdefaults, .bash_logout, and .bashrc. This prevents a user from changing aspects of his environment. Finally we secured the netscape preferences file, and the bookmarks file. A user can still change the settings in netscape, however they will not be saved, so the next person to login will be presented with the default settings.chown root /home/guestchmod 555 /home/guestchown root /home/guest/.fvwmrc /home/guest/.bash_profile chown root /home/guest/.Xdefaults /home/guest/.bashrc /home/guest/.bash_logoutchmod 555 /home/guest/.fvwmrc /home/guest/.bash_profile /home/guest/.Xdefaults /home/guest/.bashrc /home/guest/.bash_logoutchmod 444 /home/guest/.netscape/preferences /home/guest/.netscape/bookmarks.htmlchown root /home/guest/.netscape/preferences /home/guest/.netscape/bookmarks.htm
First, let me set the scene: today is January 22. The important events of this day are:
Let's get the Microsoft information out of the way first. My understanding is that a compromise has been reached between Microsoft and the justice department--the Internet Explorer icon will not appear on the desktop, but the browser itself will still be included. As the easiest way to get a new browser is to download it off the Internet and 90% of all personal computers today come with Microsoft Windows, it seems that all we have done is make it a little harder for Internet Explorer to be on 90% of the desktops. Hopefully, there will be further developments in the Microsoft vs. the U.S. Justice Department game.
The Netscape item has two parts. The first, making the browser available for free really is a necessity; 90% of new personal computers come with Windows and, thus, Internet Explorer. Whether IE is better than anything Netscape offers or not isn't the issue if one comes with your computer and you have to go buy and install the other one. Numbers back up this statement. Netscape used to account for about 90% of the browser market while 60% is probably the case today.
The good news for Netscape is that they have managed to shift their revenue stream away from stand-alone client software. Their own numbers show that in the fourth quarter of 1997 these revenues were only 13% of total, down from 45% a year earlier.
By far the most interesting part of Netscape's announcement for the Linux community is the fact they will release the source code for Communicator starting with 5.0. Sure, this will also make a change for them in the Windows arena and may force Microsoft to make some brave decision as well, but let's look at what this does for the Linux community.
The first thing I see is talk on the Gnome mailing list about a version of Navigator using Gnome. Call it Gnomescape, it is potentially a full-featured browser with a look and feel that is likely to become the Linux standard. [For more on Gnome see the "KDE and Gnome" article by Larry Ayers in issue 24 of Linux Gazette January 1998.]
Netscape claims they are releasing the code to allow the Internet community to contribute to the development. (I expect Linux helped them realize that is possible.) For us, this can mean that instead of complaining about Netscape bugs, we can fix them. I expect, based on Linux history, the best, most bug-free version of Netscape will appear on Linux systems first.
Free Communicator and free source code means that Linux systems become a much cheaper choice for "Web Appliances". It also means inexpensive kiosks at shopping malls, car dealers, etc. While I am sure Netscape made this decision to help their competitive position with Microsoft, I think we will see a huge impact on the Linux scene. Of course, if Linux replaces Windows as the operating system installed on 90% of the PCs sold today, Netscape will be as happy as the Linux community.
What's still up in the air is what sort of license the source code will fall under. GPL is one choice; a license more like that of BSD is another. Check out "Linux News" and the discussion groups on our web site to get up to the minute information on what is happening.
Randy AppletonLarry AyersJim DennisRick DearmanBernard DoyleMichael J. HammelPhil HughesMike ListRussell C. PavlicekMartin VermeerThanks to all our authors, not just the ones above, but also those who wrote giving us their tips and tricks and making suggestions. Thanks also to our new mirror sites.
Thanks to my wonderful husband, Riley, for the hard work he has done the last three months to help get LG out. He has, however, decided that he no longer wishes to take full responsibility for Linux Gazette so I am once more in the driver's seat. Whether or not I decide to outsource it again remains to be decided.
In the meantime, I'm having fun and enjoying all the mail and good articles that you guys have been sending in. Lots of you have subscribed to our announcement service and it seems to be working well -- no complaints!
Linux Journal has redesigned its Linux Resources Page. Check it out and give us your comments and suggestions. We'd like these pages to be community effort and will provide space for discussion groups and Linux projects. Just get in touch with our .
Have fun!
Marjorie L. Richardson
Editor, Linux Gazette,
Linux Gazette Issue 25, February 1998, http://www.linuxgazette.com/
This page written and maintained by the Editor of Linux Gazette,