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LINUX GAZETTE
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By The Readers of Linux Gazette

See also: The Answer Gang's Knowledge Base and the LG Search Engine


Hiding your email on websites from spammers

Sat, 28 Sep 2002 22:02:01 -0700
Benjamin A. Okopnik (the LG Answer Gang)

Here's a way to "munge" your email address on your Web page so that spammer's bots can't grab it:

perl -we'map{printf"&#%s;",ord}split//,pop' user@host.com

Use your address, and stick the output into your HTML where you'd normally use your address. It will display correctly, but all that the bots will see will be something like

user@host.com

Of course, if bots get smart enough to undo this, it won't help... a friend of mine also uses tricks to confuse them as to where the @ sign has gotten to... SGML comments within their domain name, stuff like that. Yet another shows their address and phone number within a PNG of their business card (although, admittedly, this is not lynx-clean).
A combination of such tricks, combined with a couple of "sentinel" addresses which look legit but are only for spambots to find, should aid you greatly in both reducing the total spam, and in having bait to feed to Razor to reduce the overall spam even further. -- Heather


Help on LILO

Tue, 08 Oct 2002 02:36:22 -0700
Tres Melton (class5 from pacbell.net)

I can usually resolve LILO issue myself but I read your help solutions out of curiosity. The one thing that I noticed that you missed (hopefully -- I only skimmed your replies) is the fact that LILO is printed one character at a time. Each character means the following...

Characters


Description

none


LILO has not yet started. Either it was not installed or
the partition is not active

L errorcode


The first stage boot loader has been loaded and started.
However, the second stage boot loader cannot be loaded.
The errorcode typically indicates a media problem, such
as a hard disk error or incorrect hard disk geometry.

LI


The second stage boot loader was loaded, but could not
be executed. Either a geometry msimatch or by moving
/boot/boot.b and not running the map installer.
Or the "lba32" option was specified and the BIOS or drive cannot handle it. Solution: switch to "linear". -- Mike

LIL


Second stage boot loader started, but could not load the
descriptor table from the map file. Typically a media
failure or by a geometry mismatch.

LIL?


Second stage boot loader loaded at an incorrect address.
Typically a geometry mismatch or by moving /boot/boot.b
without running the map installer.

LIL-


Descriptor table is corrupt. Either a geometry mismatch
or by moving /boot/boot.b without running the map
installer.
That is, you made it into 32 bit or other paged memory processing, beyond what old DOS hacks call "real mode" -- but the page descriptors don't look good, and LILO refuses to jump to hyperspace with such ugly coordinates. -- Heather

LILO


Everything successfully loaded and executed.
Statistics: 3 out of 6 troubles mention the map installer. Just run /sbin/lilo again and see if it helps.
4 out of 6 mention geometry. linear, lba32, and compact are all options which relate to geometry; if you're using one, try changing this and running /sbin/lilo. But you just might have to tweak CMOS instead. For instance, LBA32 often needs to be turned on in CMOS before the lilo option can do anything.
2 mention media problems. Sorry. If you're lucky the mangled piece of disk is not track 0, and you can just copy fresh lilo bits out of their package, to new disk locations that aren't bad. For goodness' sake run fsck -c to get the bad spots marked useless before going much further. And make sure your partition table is good.
And #1 on the "whap yourself on the forehead" list: If you get no LILO response at all, make sure that /etc/lilo.conf says boot=/dev/hda (or sda if you're on SCSI and not a numbered partition like /dev/hda1. -- Heather

Courtesy of Linux Tutorial

http://www.linux-tutorial.info/cgi-bin/display.pl?68&0&0&0&3

Regards
Tres


bad clusters

Mon, 30 Sep 2002 16:28:55 -0700
Dan Wilder (dan from ssc.com)
Question by aneta (aneta from cox.net)

where do bad clusters come from?

The Great Bad Cluster Cabbage Patch in the Sky.

Seriously, bad clusters represent errors in a file system. They may be soft errors, for example where power failed or the OS crashed during a write to disk. It could be where there are some bad bits on RAM that was used to hold data on the way to the filesystem. It may be that the computer has problems with its power circuitry, either in the power supply or in the power distribution circuits, filters, regulators and so on on the motherboard. Or the underlying problem may be failed sectors on the disk.

also my friend has an HP pavilion with windows 98, she has 3 bad clusters and her computer is running anciently slow. i'm running a windows 95 format disk to reformat her computer and so far it has been running for 3 days just trying to recover the allocation units, why is it running slow, and will re-formatting take care of some of the problems since she does have bad clusters?

In either the Linux case, which is what this mailing list is about, or other operating systems, it's time to enlist the services of somebody with serious diagnostic tools and skills. Simply reformatting the disk is very unlikely to cure the underlying problem, unless it was merely due to a power glitch. It probably wasn't a good idea to begin the reformat prior to consulting an expert, as you may have erased some of the information that would lead to a correct diagnosis.

Or, it might just be time to replace the computer.

I wouldn't rush to that as the first thing; it may only be the hard disk that's bad, not the whole machine.
If a bad controller on the motherboard is doing it, well yes, then it's probably easier to just replace the box. -- Heather


CDRW plugging-it-in mini-howto

Tue, 24 Sep 2002 15:13:26 -0700
Jim Dennis, Karl-Heinz Herrmann, Dan Wilder, Mike 'Iron' Orr (the LG Answer Gang)
Question by Dale & Shelby (rlewis97 from sheltonbbs.com)

I know nearly nothing about drives. I purchased a cd-rd drive and can't get it to work. I have installed the drive, but it won't work. The switch on the back of the drive is set in the middle. There is no writing on the switches, so I assumed the switch was set on the slave from the factory. From what I have read it seems like it has something to do with my ide. But I have no idea how to set that. The drive does not show up in my hardware properties. Do you think you can help?

Thanks in advance

[JimD] .... That's an MS Windows dialog box. Right?
If so you should call Microsoft and see if they offer support for their products.
Strictly speaking, it's the CD bay manufacturer to call, not the MSwin guys. -- Heather
[K.-H.] Start earlier -- bo into bios setup and do a "drive detect" if available. Does it show up there? Also All IDE CD drives I had gave some boot message during the BIOS search for IDE devices. This is before the box with the summary comes but after the memory countup.
If it's not there the hardware is not detected and something is quite wrong on hardware level.
[Dan] Try the HOWTOs...
You'll probably have to rebuild your kernel or load a module to support these. If you need help with that, check back here after you've taken a look at the HOWTO.
[JimD] The best resource for this topic right now is probably:
Winfried Trümper's CD-Writing HOWTO
http://www.tldp.org/HOWTO/CD-Writing-HOWTO.html
... though there are a couple of comments at:
The Answer Gang 65: cd-writing mini-howto
http://linuxgazette.net/issue65/tag/17.html
In general IDE CDR/CDRW drives under Linux are accessed through the SCSI emulation layer. Thus you normally have to build the ide-scsi module (either into your kernel, statically, or as a loadable ".o" file). Normally you'd also have to pass the kernel a command line hint like hdc=ide-scsi which will force the system to direct all traffic to that IDE device through the SCSI emulation subsystem.
The oddity of this is that it affect normal access to CDs via that device, too. Thus to mount a normal CD in that drive you'd use the /dev/scd0 (or other /dev/scd*) device node. Writing to CDR and CDRW media would generally go through the /dev/sg0 (or similar) devices -- sg is "generic scsi device" (printers, scanners, etc). (Actually the cdrecord command uses a three part bus, ID, LUN address for this).
[Iron] If it's a new drive, I would return it and say the inadequate labeling is preventing you from using the drive. Maybe that will goad the manufacturer into doing what practically all other manufacturers have done: put labels with diagrams on the drive.
An IDE drive normally has a jumper (not a switch) with three positions: "master", "slave" and "cable select". Some also have a position for "single". IDE cables have three plugs so they can fit two drives on one controller. If this is the only drive on the cable, it must be "single" (if such a position exists) or "master" (if it doesn't). If there is another drive on the cable too, one must be "master" and the other "slave". "Cable select" was one of those nifty new ideas that never caught on, so don't bother with it.
If an IDE plug fits it, it's probably an IDE drive. I've never seen one with a switch instead of jumpers, but it's possible. Is it an external drive? Those would be more likely to have switches.
If the switch is unlabeled you'll have no choice but to try all three positions and see which one works.
The IDE cable should be connected with the red stripe facing toward the power cable. On the motherboard, the red stripe should go toward the pin marked "1".
The power cable is connected, right?
It's possible it's not an IDE drive at all but a SCSI drive. The plug would be a different shape and the switch would have numbers (0-8 or 0-16).


1 ut2003a.tgz: The archive is corrupt

Wed, 02 Oct 2002 20:52:02 -0700
Dan Wilder, Rick Moen (the LG Answer Gang)
Question by Justin Medeiros (jmed from shaw.ca)

hey i have downloaded a .tar file and it says its corrupted, and i changed it to .tgz and it's still corrupt, any ideas?

thanks.

[Dan] Believe tar. The file is corrupted. Throw it away. Download it again.
You didn't say how you downloaded it.
Rick Moen proceeds to answer the question he should have asked ... "how do I keep it from arriving corrupted?" -- Heather
If you were using the ftp protocol, make sure you were using binary transfer mode, not ascii mode.


How to delete LINUX?

Fri, 18 Oct 2002 01:43:28 -0400
Daniel Washko (the LG Answer Gang)
Question by Suijian Zhou (zhous from wicc.weizmann.ac.il)
This is the best framed question of this type I've seen in years, and Daniel had a fast, neat answer ready to hand. So I'm publishing it even though it's an FAQ.
As long as later editions of Windows continue to have a tool to replace the MBR cleanly, this note will continue to be useful. -- Heather

Dear Friend,

I have a computer with two operating systems: Win98+Linux. Now I want to delete the whole Linux system to free its space into Win98. The selection of boot for a certain operating system is by LILO at start. Can you tell me 1) How to delete the Linux? 2) After delete Linux, that means delete LILO too, so can I still boot the computer into Win98?

Many thanks

Use a win98 startup disk or the win98 cd to boot. Run fdisk, delete the linux partitions using the non-dos partition optoins. Then exit, run fdisk /mbr. Reboot with the disk or disc, run fdisk again and create a new dos partition. Reboot, format the parition. Why you would want to do this is beyond me. You should be deleting the win98 partition to free up some disk space for the linux partition.


How to write C program?

19 Oct 2002 20:45:15 +0530
Ashwin M, Rick Moen (the LG Answer Gang)
Question by maud (maud007 from 163.net)

Hello,I am a university student from China. Now I write C program with vi,and compile with gcc,but I find write program like this is unefficient.There are very good tools for Windows, like Visuanl C++, Tubro C/C++ etc. So I want to ask what tools we can use in Linux and the step to write a program.

If you find vim and command line gcc too rudimentary for your taste, a lot of visual-like and IDE tools for Linux are available. Some of the popular ones are -


KDevelop (KDE/Qt based)
Glade (Gtk based)

If you cannot find them, then maybe you have not installed them from the CDs. Please do so and give them a try. They ship with all popular Linux distros (distributions).

... ashwin

In case it will help, I maintain a list of all known Linux IDEs / GUI Builders / RAD tools, at http://linuxmafia.com/~rick/faq/#idedev . The list has passed 100 entries.

... Rick Moen


cd-writer device driver

Sat, 05 Oct 2002 10:09:54 -0500
Karl-Heinz Herrmann, Pradeep (the LG Answer Gang)
Question by Sarath Ananthapadmanabhan (sarath from scientist.com)

hello answerguy,

Hi Sarath,

It's gang now, not guy: see http://www.linuxgazette.net/faq/index.html or www.linuxgazette.com/authors

I am a final year software engineering student and I want some driver writing information. I would like to know how to obtain enough information about my cd-writer to write a driver for it. This is important for my final sem project and I can't seem to find anything on the web.Even a few helpful links would do.

You already asked this on the cdwrite mailing list and you got one answer pointing you to the SCSI MMC-3 specifications, so why not try to locate it? The cdwrite mailing list certainly has the more knowledgeable people on this particular issue. So they do expect you to know at least to some degree what you are talking about if you venture to write a cd-writer driver from scratch and they think a pointer like they gave should be sufficient. If you have particular questions/problems on implementation that will be a good place to ask again.

I read that u are an LG fan.

I am certainly not an LG fan (neither the cdrom manufacturer nor the Indian(?) electronics manufacturer (TV's and stuff) if they are not the same.

I certainly am a fan of Linux Gazette so....

The device I'm talking about is an LG GCE-8160B (16x max).Hope you can help me with it.

So -- that might be an IDE drive or might not be an IDE drive. I guess it is.

in any case: The protocol used to access these devices --- and all newer CD-writers are ATAPI/SCSI MMC-3 compliant --- is the MMC-3 specification. Actually ATAPI for CDROM drives is nothing but SCSI over IDE, so the devices understand scsi commands which are sent over the IDE hardware connection. In Linux (to be a little bit ontopic for a LINUX-questions-only) there is a ide-scsi driver which is taking care of the scsi over ide commands part, so you don't have to worry about that when writing the driver. (NT BTW does the same, burners and Co are treated as SCSI devices).

SO:

  1. try to get hold of this specifications like typing "mmc-3 specification" in www.google.com... but this is not the first hit there and will require some digging. It is well possible that you have to buy that in printed book form from somewhere. I get lots of *.msdn.* hits, maybe you find something generic there too. you are trying low level hardware programming so getting used to that kind of bit poking manuals will be unavoidable I guess
  2. get cdrecord and/or cdrdao and have a look at their code, especially the library libscg might be interesting since it's handling all the low level data transfers
  3. be aware that this is a major project, i.e. to write a successful driver for at least most of the CD-R's features

If you need info on how to write a device driver for Linux there is a HowTo out there..... hmm. (some poking about in the web-shelves ensues)

What I could find are the SCSI-programming howto's:
http://www.tldp.org/HOWTO/HOWTO-INDEX/programming.html#PROGINTERFACE

Look for SCSI one page down.

(it doesn't evade view for long, though.) There is a Linux kernel module programming guide:

http://www.tldp.org/LDP/lkmpg/mpg.html

K.-H.

It's quite old and the interface is a bit changed in 2.4(from 2.2). The best reference for driver writers is Alessandro Rubini's book

Linux Device Drivers
http://www.oreilly.com/catalog/linuxdrive2

This is a must if you are planning to do any serious kernel module hacking. It's quite affordable too. I guess it costs around 170/- in india.

--pradeep


Cheap duplex fix

Tue, 08 Oct 2002 12:22:32 -0400
Allan Peda (pedaa from rockefeller.edu)
and an alternive answer to same problem, by Ben Okopnik

Hi:

I wanted to share a trivial printing fix, and ask a question. We recently upgraded here to a duplex printer, which worked terrific, except that when duplex printing from my Redhat 7.3 box every second page was offset an extra centimter to the right. It didn't matter which application I used either.

I tried a few different drivers, but they all had this problem. Rather than approach this trial and error I decided to intercept the input Postscript and fix the margins. Admittedly this is not finding the cause of this problem, but it works.

I edited the /etc/printacap file (after backing it up) to point to a different magic filter wrapper for the duplex printer, and copied the original wrapper to a new "improved" one.

I called this mf_wrapper_duplex, the diff output from the original mf_wrapper and mf_wrapper_duplex follows:

diff  /usr/share/printconf/util/mf_wrapper
/usr/share/printconf/util/mf_wrapper_duplex
45c45
< /usr/bin/magicfilter-t "$TMP_FILE" $DEBUGSTRING < /dev/stdin
---
 > pstops -b 2:0\(0,0\),1\(-1cm,0\) < /dev/stdin |
/usr/bin/magicfilter-t "$TMP_FILE" $DEBUGSTRING

I use pstops to adjust margins on the postscript data stream, using the '-b' option to strip binding information, and push the margins over 1 centimeter to the left via the 2:0(0,0),1(-1cm,0) rule, - see the pstops manual. I then restarted lpd.

Of course this is not a perfect, or even a really correct solution, for one the printconf utility will overwrite this, so it should be put in /etc/printconf.local but I was getting really annoyed at the margin drift on the even number pages. Also, I believe the data stream into magicfilter might not be postscript, so it would break on this as well.

I think this should really be done in magicfilter - does anyone know how to hack this nicely?

Thanks
Allan


For quite a while now, I've had a printing problem - plain text always came out shifted about an inch to the left, and some characters "fell off" the page. Until recently, I didn't bother fixing it - instead, I'd bring up the text in "vim", issue an ":ha" (hardcopy) command, and presto!... of course, this required setting up "vim" to print (see my "Fancy Printing in Vim" tip in LG#79.)

However, I really dislike it when things don't work the way they should, and I got around to this recently. Since I use "magicfilter" to process all of my print stuff, I simply edited "/etc/magicfilter/StylusColor-II@720dpi-filter" (which is what I use for my Epson Stylus), and changed the last entry, like so:

See attached leftshift.sed.txt

Note that I also add a formfeed (FF or ^L) at the end of the file. This character is not a '^' followed by an 'L' - that won't work! Instead, use a Real Editor ('vi', or something else that lets you enter raw characters). In "vi", as an example, press <Ctrl-V> ("raw character entry") followed by <Ctrl-L> ("formfeed"). Also, you may need more or fewer spaces than I did; simply adjust that string of spaces in the beginning of the "sed" expression.


odd use for eject

Thu, 24 Oct 2002 15:33:02 -0700
Jim Dennis (the LG Answer Guy)

Eject is of course, the command to spit out the CD that's inside your system, rather like the Macintosh does.

If you're a system admin at a large rack of pretty much the same machines, you can double-check which one your KVM switch is pointed to right now... by making it 'eject' and spit out its CD tray.

Then it'll be obvious!

If you have ever rebooted the wrong machine in your server rack or colo facility, you definitely can use this trick to keep that from happening again :)

Also handy if you have a habit of ssh'ing into any of several workstations in your development offices. You can probably even hear the whirring of the drive tray. But don't do it if you know the boss keeps their coffee in front of the CD bay...


emacs

Fri, 25 Oct 2002 09:36:09 -0700
Mike Orr (Linux Gazette Editor)
Question by Ben Okopnik

I'd imagine there's someone here who's fairly knowledgeable in Emacs...

Fairly knowledgeable, no. Slightly knowledgeable, yes.

So, I pull down the "Tools" menu, and choose "Read mail". OK, everything's fine. I exit Emacs, not saving anything... and shortly thereafter note, with an ice-water-down-the-back shock, that my "/var/mail/ben" is GONE. Zeroed. Empty. WHAT THE FSCK???

Fortunately, after some seriously POed muttering and high-speed maneuvers with "find", I thought: "what if Emacs did something weird with it? It shouldn't have just deleted the thing!" So, I open up Emacs again, "Tools/Read Mail"... and there it is! Big sigh of relief, and about a dozen blind avenues later I figure out that it stuffed my mail into a file called "~/RMAIL" and munged the format.

Typical emacs arrogance. It assumes that its way of handling mail is the best and that other mail utilities are stupid not to conform. I had the same problem when I tried emacs mail in 1990. And I stopped using emacs mail for precisely that reason: it didn't handle mail in a way that was compatible with other mail utilities.

So, my question to you guys and gals is, is Emacs ALWAYS this bloody rude? That is horribly intrusive behavior, as I see it: I never explicitly asked it to change, delete, move, mung, or do anything of the sort to my mail. I could see where a new user would be totally lost. If I did something stupid, OK - I'll just be extra-extra cautious of the beast. If, however, that's Emacs default behavior, I'm deleting it off my system with extreme prejudice and it shall never darken my STDOUT as long as I live.

Ben: Emacs is so rude!

Emacs: Why didn't you read the FM?

Ben: Why didn't you give me a warning the first time I ran it, O Editor That Calls Itself "Self-Documenting"? You're the one that's using an esoteric, incompatible format.

Emacs: It was probably the standard format in the environment where emacs mail was written, and then remain unchanged three decades later.

Ben: I'll show you who's boss!!! I'm going to uninstall you with extreme prejudice!!

Emacs: Bigot!

Ben: Bloated piece of crap! You've got more features than Internet Explorer, nyaa, nyaa, nyaa!

Emacs (Eliza mode): Is the fact that I'm a bloated piece of crap the reason we're having this conversation?

<*Splort*> <FOTCL>

Mike, that's one Diet Coke with lemon you owe me. I does not belong on my keyboard, and spraying it out through the nose hurts.


how many roots?

01 Oct 2002 04:07:06 +0100
mike, Sayamindu Dasgupta, Heather Stern (the LG Answer Gang)
Question by Maria Diaz (Galopwitch from aol.com)

I have a two part question.

How many root directories can you have in Linux?

How deep do you want to chroot? -- Heather
OOOH! Nominated for Answer of the Year. -- Ben

[mike] File systems work a bit differently in linux. There is only ever one root directoery wich is /

All partions or drives are mounted on subdirectories from this root

drives and partions are numbered like so

/dev/hda		first Hard disk
/dev/hdb		second hard disk
/dev/hda1		first partition on first hard disk

[SGD] Basically - it is not possible to have more than one root directory in the box

The real answer is "one at a time"
The guys here are correctly describing a normal directory setup.
However, an application can be working from a deeper directory than the real one; that's called a "changed root environment" or chroot and is actually done all the time by things like Apache and postfix and qmail. -- Heather

I you have more than one disk drive, what steps do you have to perform in order to make them available for use.

[SGD] what you can do is mount your other harddisk under a subdirectory for example, if you have /dev/hdb as your secondary harddisk, and you want to use the first partition of that harddisk under linux, just issue the command

mount -t <filesystem> /dev/hdb1 <mountpoint>

here <filesystem> may be vfat (if it's fat32) or ext2, or ext3 <mountpoint> may be any empty directory in your box - usually /mnt/disk2/ or something like that.

Yup, this is so. You can have lots of partitions, mounted anywhere you want, including on top of each other, though I don't recommend covering up any files as they will look like lost space.
To help make this more readable I made mike and Sayamindu's code describe the same system. I use /mnt/c when referring to a C:\ drive, I think it's nice and memorable. -- Heather

[mike] To eg add a second hard disk you could eg do this

mkdir /mnt/c
mount /dev/hdb1 /mnt/c

(assuming second drive has been partitioned and formatted)

to make this permanent edit the file /etc/fstab to add an entry like this

/dev/hdb1               /mnt/c                  vfat    defaults     0 0

and save the file (please note the above file system is fomatted for w32 - adjust to taste)

Your response would be greatly appreciated

Thanking you in advance

Maria Diaz

You're very welcome! -- Heather


[LG 82] help wanted #3 Postfix hates Outlook

Thu, 26 Sep 2002 23:48:34 +0000
Edward (itored from hotmail.com)

Shahid,

Postfix is an SMTP server and Outlook will send mail out through it but not get mail from it. The problem seems to be there is no POP3 server running. Have a look here: http://www.postfix.org/addon.html#pop

for info on obtaining and setting up a POP server.

Edward


Fun With Ioctls

Mon, 28 Oct 2002 00:23:56 -0600
Chris Gianakopoulos (cgianakop from 1stconnect.com)

Hello Gang,

A while ago, Shreedar V. K. from India asked for a program that would list the IP addresses for all of his interfaces. Back then, I joyfully referred him to one of those Stevens TCP/IP books. We got quite a thread from that response. I like that.

I got bored today, so I cranked out a simple program that prints the interface names with their associated primary IP address. I intentionally omitted the display of alias to keep the program simple. It's really a quick hack.

The purpose is to illustrate why the simple solutions, provided by Ben O., really make sense. Still though, I never turn down a challenge. Everyone can use and hack it at will. Just compile the program and run it. It takes no command line arguments. Example output, as well as the program listing, are displayed below.

Good night, Chris G.

See attached interfaces.c.txt

Hey, pretty nifty! I saved it in interfaces.c and here's what using it looks like -- Mike
% gcc -o interfaces interfaces.c
% chmod +x interfaces
% interfaces
lo: 127.0.0.1
eth0: 216.39.[censored]
eth1: 10.0.0.1

Thanks Mike! The program kinda shows how much work goes into our beloved network programs such as ifconfig.

Later... Chris G.


lkml

Thu, 24 Oct 2002 11:05:55 +0530 (IST)
Karl-Heinz Herrmann (the LG Answer Gang)
Question by Brad Herring (webgineering from xtra.co.nz)

Hi there,

I'm doing a report for Uni, I was wondering how many subscribers are there to the Linux Kernel Mailing List? Is there a more popular list? Estimates are fine.

Hi,

I have no idea, so the traffic on that list seems rather high (~1000 posts/day).

You might want to subscribe and send administrative commands like "help" "info" and if available "who" which would give you a list of all subscribed members. These commands depend on the exact mailing-list managing program but most have these options.

K.-H.

Many people subscribe to digests so they can get their mailing list stuff a little less often, all in one chunk.
But there is a brave soul who actually summarizes the Linux Kernel Mailing List, and publishes the results on a website he calls Kernel Traffic: http://kt.zork.net/kernel-traffic/latest.html
The Linux Weekly News notes about what's going on in the kernel are available to LWN subscribers :)
But you can see some of the latest patches some of these guys have whipped up at http://lwn.net/KernelPatches/ ... and they warn that these things might drink all your beer. From what I know of development parties, perhaps they are speaking from experience? :) -- Heather

WHIZBANG Patch


Adds /proc entry for refrigerator chilliness support.
Highly experimental, the beer keeps disappearing. Hope
to fix in next rev. Suspect memory leak in purchaser
algorithms.

workaround: we recommend Jolt Cola; or home zymurgy kits
stored in a seperate directory.


When the Weekend Mechanic loses his tools

Wed, 2 Oct 2002 08:58:42 +0100 (BST)
Thomas Adam (The LG Weekend Mechanic)

How many of you have been guilty of using mc (midnight commander), hitting the key sequence "<ALT><SHIFT><?>" before, and then filling out that nice dialog box to find the file that you require?? Don't lie, we've all done it (Hi Ben :-) ).

<blink, blink> Thanks for the vote of confidence, Thomas... but I didn't even know about that feature until you mentioned it. <grin> So, _now_ I'll be guilty of it - maybe. I'm pretty used to "find" by now, and would miss things like "-exec" too much to use some constraining box. -- Ben

I actually wrote that? :-) he he.....

Oh no, Ben. I simply meant that as you keep promoting the use of "mc" for things like: rpm viewing, tar/gz viewing, etc, it was logical (?) to assume that you'd have used the "find" feature occasionally? :-)

<grin> It's one of the things I like about it; after all this time of using it (and using Norton Commander, which is was modeled after, for some 15-20 years before then), I _still_ discover cool new features occasionally. I wrote Miguel a nice letter back when; he deserves lots of kudos for this one. -- Ben


ATI Rage M4

Thu, 26 Sep 2002 12:59:34 -0500
Ben Okopnik (LG Answer Gang)
Question by Mark Gorat (MarkG7 from netscape.net)

I would like some help configuring my Dell Latitude C800 display (ATI Rage M4 16MB). No matter what magic I try to accomplish with Xconfigurator or hand editing of the /etc/X11/X86Config-4 files, I can't convince my XWindows display to set-up in anything but 1600x1200. This is very hard on my varilux bespectacled eyes.

[Robos] Just as a short answer (no time right now): down in xf86config-4:
 SubSection "Display"
   Depth           16
   Modes           "1024x768"
 EndSubSection
 SubSection "Display"
   Depth  24
   Modes           "1024x768"
 Exchange the numbers (swap em) to something like this
 Modes "1024x768" "1600x1200"
Robos is right on the dot. From my own "/etc/X11/XF86Config-4":
Modes "1600x1200" "1024x768" "800x600" "640x480"
Works fine on this Dell Inspiron. -- Ben

Some posts elsewhere have said to use <Ctrl><Alt><-> or <Ctrl><Alt><+>, but this seems to have no effect. Any help would be extremely appreciated.

Thanks
Mark Gorat

Something I just realized: if you're hitting <Ctrl><Alt><-> or <Ctrl><Alt><+> using the "_/-" or "+/=" keys, that definitely will not work - you need to use the keypad plus or minus. On most laptops - certainly on a Dell - that works out to <Alt><Ctrl><Fn> with the "blue" plus or minus (the ":/;/+" and "p/-" keys.) -- Ben


Cannot Login as root at all

Tue, 24 Sep 2002 01:15:36 -0700
Heather Stern (star from starshine.org )

This is a multi-part message in MIME format.

(sigh. The MIME has been put in a box on the sidewalk. Maybe that will help him communicate.)

Hi...

I had installed RedHAt 7.0 It was working perfectly fine. One fine day I cannot login at all.. After booting it says login... and when I type my root user it doesnot ask for password.. but just comes back to the login again... But I can access it from Webmin from a remote computer.

Please help me.

Thanx Danny

Check your securetty file, or PAM. Either of them could suggest to the system that root cannot be trusted to login from where you are at.

If it were a regular user, but root could login, I'd suggest checking if the nologin file is present.

You could also be on a system that cannot handle passwords longer than 8 characters, but be trying to work with a longer password, or be using something that is not shadow-aware while your password is stored in the shadow file. This used to cause trouble when Gnome was much younger.


I would have called, but...

Wed, 9 Oct 2002 07:30:05 -0700 (PDT)
Jay R. Ashworth, Heather Stern (the LG Answer Gang)
Question by satheish (hotshotis from yahoo.com)
Imagine our sysadmin's surprise when a help question came in through the customer service webform for Linux Journal ... (empty fields snipped) -- Heather
Subscriber:                          hotshot
  Comments:

 do we have pc2phone dialer software for linux ?

      Name: satheish
   Country: India
     Email: hotshotis@yahoo.com

Form: CustomerService    Version: 1    Request ID: 6584
[Heather] Hotshot, your question has been forwarded to the Linux Gazette Answer Gang. Linux Gazette is a web-based magazine hosted by the same publisher as Linux Journal. I greet you as the editor in charge of the monthly column.
I took a brief look at the internet search engines to see what you appeared to be talking about. There's apparently a company offering software which turns your computer into a phone, provided that it's plugged into a phone line and you have a full service sound card. It also looks like "2.9 cents a minute" comes up a lot.
There are a lot of internet-phone applications - voice conferencing is especially popular. If you type "phone" as a keyword into the application search engine at Freshmeat (http://freshmeat.net) you'll have about 250 projects to check on. You may want to start at the category : Communications :: Internet Phone.
As for the 2.9 cents a minute that just depends how they implemented it.
My suggestion would be to contact the folks who make the "ordinary" PC2Phone software and ask them the same question - is it available for Linux, and if not, what is the protocol used. If the protocol is an open standard, note it down, and ask them what settings you'll need to set your Linux software to, in order to enjoy their service.
Good luck in your quest.
[jra] I believe you mean "client software for a voice over Internet phone service called "pc2phone"... which appears to actually be net2phone...
and I'd recommend persuing the results of
http://www.google.com/linux?hl=en&lr=&ie=ISO-8859-1&q=net2phone
there appears to be some useful answers in there.
Please see also
http://www.tuxedo.org/~esr/faqs/smart-questions.html


Getting rid of offensive content on your hard disk dreged up by your web browser

Wed, 9 Oct 2002 11:02:15 -0700
Mike Orr (Linux Gazette Editor)

[Forwarding to LQO as a 2-cent tip. Anyone want to write such a script or write an article about it?]

The original message was a spam promoting commercial software that would scrub your (Windows) system of "offensive content" (pornography, drug references, terrorism references) you may have accidentally dreged up while websurfing.

Part of the scare tactics it mentioned is a claim that you can get convicted for child pornography merely for visiting a site once that has child porn pics on the home page, even if you didn't know the nature of the site beforehand, or 3rd-party Javascript sent you there without your approval, or you never saw the pictures in the visible portion of the window. This => cached porn pics on your HD => discoverable evidence of a crime => why you need this commercial program.

[tag-admin] Speak right up, what's the best way to delete offensive content that may have been automatically saved on your hard disk while you were websurfing?

Can you say, "Open the preferences/settings dialog and press the 'Empty Disk Cache' button?" I knew you could.

[Don Marti] What about history and cookies?
A script to clean all traces of web activity from your .mozilla directory (except cookies from sites you like) would be an interesting exercise. All of these files seems to have some potentially "incriminating" info in them:

history.dat
downloads.rdf
localstore.rdf
This should work just fine. However, there's other semi-personal info scattered throughout, e.g., info about filenames to which you've printed content in "prefs.js", etc.
<shrug> You could just whack the whole "~/.mozilla" directory if you're really concerned.
Wind*ws people need expensive software to do this... amazing. -- Ben

See attached scrub-mozilla.sh.txt

The canonical way to deal with this in email gardens is to wipe out the guest user home on logout ... completely ... and re-establish it via popping open the tarball of its homedir again.
This, together with having the system be one-user and wiping the /tmp directory, should be sufficient to most purposes. It also keeps nameless guests from using your e-garden as a storage bin. -- Heather


At a loss for words

Tue, 15 Oct 2002 18:40:02 -0400
Ashwin N, Thomas Adams, Frank Rodolf, Jay R. Ashworth (the LG Answer Gang)
Question by Lon Diffenderfer (profitrocket from nmax.net)

Hi,

My name is Lon Diffenderfer. I am looking for a way to convert some very important files created by my father in SCO Lyrix into a .txt file. Is this a simple procedure or will I need a the help of a professional? Is there a file conversion program that I can purchase or download that would be able to handle this job? I thank you in advance for your time and assistance.

Best Regards,
Lon Diffenderfer

[Ashwin] Now can you please elaborate on what kind of files these are? Knowing the file format will be essential ...
[Thomas] Ashwin, I agree with you that the filetype is important. Indeed, Lon could acheive this by issuing the command:

file /path/to/file
and then reporting it back to us. This would, as Ashwin has said, help us in determining which program(s) to use.
[jra] Lyrix was a third-party word processor which ran under Xenix.
SCO bought it (or it's resale rights), and I haven't seen it in years. I strongly suspect that you're going to have to hunt up copies of both Xenix and Lyrix to open those files...
[Frank] ... Lyrix was once known as Unixplex, I seem to remember.
While I don't know exactly anymore, I seem to remember that it was always one line of text, followed by a line of formatting code below it, each line ending with a <CR>, a new paragraph is signaled by an empty line.
[Rick] be aware that at least two other software efforts have borne the name Lyrix: a computer-telephony product from Lyrix Systems, Inc., and early versions of the excellent TeX-based graphical document processor subsequently renamed "LyX".)
[Thomas Adams] But in most cases, I would recommend the use of the program: "strings", which trys to report back useful "character literal" information. You could try issuing the command:

strings file | less
where "file" is the file that you are trying to view. (I've piped it through to "less" for convenience, although:

strings file >& ~/some_file
is perhaps better if you want to store the information)
N.B. Strings does work on ELF files, but the result is somewhat unpredictable.
[Frank Rodolf] Lon, if all you need is the text portion, you should do quite nicely with the strings command, as Thomas writes above.
I heard rumors that there has been some conversion utility (lyrix2wrd, or something like that), but when a friend of mine needed that a while ago, I was unable to find it.

To all who replied, "THANK YOU!"

[Thomas] You're welcome!!!
I'm glad that people such as Jay, and myself, were of some use. Makes a change actually!!
He he....

With the information you provided, I was able to find a local professional who had administered Xenix systems in years past and was able to use "strings" to recover the data. I still do not understand exactly what he did, but I am elated and very grateful to your group for your assistance. If this is the kind of help I can get for Linux, maybe it's time to learn it and switch.

[jra] Probably. :-)
Outstanding; glad to ehar you got your data back. Now you understand why Unix people (and especially Linux people) are fond of textual configuration and data files whenever possible...
What he did was to use the Unix strings(1) program, which sifts through a [random] file looking for strings of characters that appear to be ASCII text, extracting them from the surrounding (binary) data, and printing them on it's output. Once you do that, it's usually just a cleanup pass.


need your help

Sun, 29 Sep 2002 15:55:30 -0700
Rick Moen (the LG Answer Gang)

question

You are the Linux system admin of your company, and an employee has forgotten his password and cannot login. How would you reset this employee's password?

su - passwd mrforgetful

question
you are sending mail to an "answer gang" list with potentially a big number of people reading it... using ordinary email clients. How do you send them plaintext only to not waste lots of bits?
http://expita.com/nomime.html
question 2
does HR give him a grilling first for losing this important piece of company data (his password) ? :) -- Heather


2 tips for the TAG

Thu, 10 Oct 2002 11:35:29 -0400
Don Radick (anonymous)

Folks,

you are SO GREAT, I've gotta drop you 2 tips .

System:


ABIT KT7A mb
AMD Tbird 1.3 Ghz
Nvidia Geoforce II GTS
Redhat 8.0

1

Symptom: System reboots automatically when trying to load Nvidia drivers v 3123

Solution: Turn on "Plug and Play OS = YES" in BIOS setup.

Side Effect: I had been getting this error message:

"usb-uhci: Host controlled halted, trying to restart" (USB mouse) That message is now gone, with the new BIOS setting.

[Ben] That could be very annoying... Turning P&P off is what allowed my old laptop to "see" the audio subsystem; I'd hate to be faced with a choice of "pick only one". Just as a point to consider, I'm using NVidia's drivers (v.2802) on my Dell Inspiron 8200 (NVidia GeForce2GO), and it seems stable - certainly no rebooting.

2.

Symptom: RH 8.0 default firewall killed my SAMBA shares on local net.

Solution: open up these FW rules (I suggest using WEBMIN for FW tuning, much better than "lokkit")


ACCEPT incoming protocol UDP destination port range 137:139
ACCEPT incoming protocol TCP destination port 139

Use arrows on right had side to move these ACCEPT rules above the DENY rules.

HTH,

Don Radick

you can print my name, but not my email address. THANKS!

No problem! Thanks for the tips. -- Heather


Troubleshooting GRUB

Sun, 11 Aug 2002 16:11:22 -0700
Jim Dennis (the LG Answer Guy)

Remember: GRUB numbers partitions from ZERO while linux counts from ONE So:


root (hd0,0)
kernel /boot/vmlinuz root=/dev/hda1

... and:


root (hd0,5)
kernel /boot/vmlinuz root=/dev/hda6

... note how GRUB's (hd0,0) is Linux' /dev/hda1 and GRUB's (hd0,5) is Linux' /dev/hda6


please clear my doubts

Tue, 8 Oct 2002 01:38:42 +0530
Sayan Chakrabortii, Heather Stern (the LG Answer Gang)
Question by muthukumar kalimani (ckmuthukumar from yahoo.co.in)

hai , i am muthukumar.

Hi, I'm Heather, one of the folks here at The Answer Gang. And this over here is Sayan.
I hope you don't mind that I split your message into paragraphs. -- Heather
[Sayan] Hi I will try to answer your questions one by one.

i did my B.E at vellore engg college.i have 2 PCs. (i) celeron 266Mhz with 92 mb ram (windows 9 8) & (ii) celeron 1Ghz with 128mb ram (windows 98 & xp ).

Either of these machines should run Linux just fine, although the Gnome or K desktop environments would probably feel as comparably slow as Windows on them. With a lighter window manager and some careful setup it could feel faster. -- Heather

i want to load redhat 7.1 in any one of my pc . i have few doubts in this matter

1. is it possible load linux as 3rd os on my system( ii ) ?

[Sayan] Well, of course it is. Provided you have the required amount of space left on your hard disk to install the packages that you need. You see while installing multiple operating systems you have to follow the rule "stupidest os first". So up till now you have not gone wrong. So go ahead and install Linux.
Yes.
The usual way is to clear some space for it (Partition Magic, parted, or FIPS are most commonly used) and then install Linux in the empty space. For Redhat to be the installed flavor you'd need to do this. With some other flavors of Linux (Slackware's "bigslack" for example) you would need to set aside some space, but you wouldn't need to adjust the partition types first.
If LILO replaces your master boot record, and your kernel is on the same disk, LILO should have no problem selecting among all three operating systems.
If you use LOADLIN.EXE from inside either of your Windows environments, and make a copy of the Linux kernel visible in your drive, you could add an entry to your mswin boot menu for Linux. -- Heather

2. after installation how the dos partition drives can be mounted as the system starts.

In the file /etc/fstab add an entry for the mountpoint which you'd like to use, and tell it that the filesystem type is vfat instead of ext2.
I like to use /mnt/c, myself, and set aside /mnt/a for using DOS floppies ... that is, if I don't simply use mtools commands.
THe LSB tells us that /mnt is expected to be used for temporary mounts, though, so you might prefer /home/c-drive or something like that. -- Heather
[Sayan] This issue was earlier discussed in this magazine in issue 34. You can read through it at:
http://linuxgazette.net/issue34/lg_tips34.html#young
Still I quote it as it is

...............


Mounting DOS Partitions in Linux


Date: Fri, 02 Oct 1998 17:08:23 -0400
From: Ed Young, youngej@magpage.com
Secure Mounting for DOS Partitions:
In order to open up permissions on your DOS partitions in a secure way, do the following:
Note: in the samples below, the dos usrid (63) and grpid(63) were selected so they wouldn't duplicate any other usrid or grpid in /etc/passwd or /etc/group.
Also, this solution works with Red Hat 5.1, you may have to adjust it slightly if you are using a different distribution.
  1. Make a dos user who can't log in by adding the following line to /etc/passwd: dos:*:63:63:MSDOS Accessor:/dos:
  2. Make a dos group and add users to the dos group. In the following example, root and ejy are in the dos group. To do this, add a line like the following to /etc/group: dos::63:root,ejy
  3. Add the following line (changed to suit your system) to /etc/fstab: /dev/hda1 /C vfat uid=63,gid=63,umask=007 0 0
Of course, you have to locate your DOS partitions in the first place. This is done by issuing the following commands as 'root':
     /sbin/fdisk -l
     df
     cat /etc/fstab
The `fdisk -l` command lists all available devices. `df` shows which devices are mounted and how much is on them. And /etc/fstab lists all mountable devices. The devices remaining are extended partitions, a kind of a partition envelope, which you don't want to mount. And the partition's allocated to other operating systems which you may want to mount. 4) Create a mount point for your DOS disk by issuing the following commands as root: mkdir /C chown dos:dos /C
With this setup, the C: drive is mounted at boot time to /C. Only root and ejy can read and write to it. Note that vfat in /etc/fstab works for vfat16 (and vfat32 natively for Linux 2.0.34 and above).
Enjoy...

...............

So you see you can always access your dos files SECURELY from Linux.
You may already have such a user, for dosemu or wine for example.
You can reuse one of that sort, as long as you're sure you are assigning a similar privilege. Also, you want to avoid making a userid that will classh with something else; if all else fails pick something above 65000. -- Heather

3. i am bit more confused while installing linux so please kindly send me the procedure how to install linux on the system in step by step method.

[Sayan] Big question, demands big answer. Maybe some other more experienced person in the List will be able to give better answer. But I hope you will have no probs trying to installl Redhat. But why do you want 7.1 when 8 has become available. Try to get a copy of the latest distro from your local LUG (Linux Users Group). They are always very helpful. If you can send us your location, somebody can give you the contacts of your nearest LUG. And, these new distros are soooo easy to install, you just cant go wrong.
The commercial package of Red Hat comes with a fine set of manuals. In addition you could get the current version; they've gotten up to 7.3 now.
But if you're going to buy it you might also compare with Mandrake or SuSE and get whichever looked best to you. -- Heather

what are the features available in linux.

Most things that you would expect, many that you wouldn't, and for almost any package, source code if you need it, or some particular programmers to go ask for more features. -- Heather

important things in linux. do's and donot's.one more thing

Mmm, donuts. Important things to do:
  1. Have fun. The computer is supposed to be your tool, not your boss.
  2. Be willing to read README files, and HOWTO documents. Linux is all about becoming more self reliant. Search engines are expecially handy.
  3. Once you've learned, help others with stuff that you understand. It improves the community.
  4. The perl motto "There's More Than One Way To Do It" also applies to most activities in Linux. If there isn't, probably some college student somewhere is working on another way, but hasn't gotten around to releasing their code yet.
  5. (NOT SPECIFIC TO LINUX) make backups! Whenever things are looking good, make a good copy of how it is; that way you always have something good to come back to if later things go haywire. I recommend a good backup of your present windows setups before you go ahead with your Linux setup, for example.
Important Don'ts:
  1. Don't despair. We agree that not everyone's advances in self reliance will include becoming a programmer type. There are web sites dedicated to Linux newbies, and to specific topics as well. There are also IRC channels to talk to people across the internet live about this, and mailing lists, and newsgroups.
  2. Don't send HTML attachments to mailing lists; some people get grumpy about it. (Don't worry, I snipped it.)

i have worked in linux in my college on a system with windows nt i want to how to connect the two os.thank u,muthu

Samba is the usual way. It lets Linux look like yet another Windows box with active shares, as far as its Microsoft-y neighbors are concerned. See http://www.samba.org for details.
Good luck! -- Heather



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Published in Issue 84 of Linux Gazette, November 2002

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