[Courtfields]

Some Linux notes

This page was first drafted in January 1997, when having spent a significant part of the preceding two years investigating Linux, and having found it a very useful tool, I started throwing together some notes and observations, as much as an aide memoire for myself as anything else.  Since then (is it really nearly 12 years?) some notes have been updated in dribs and drabs, whilst others have never even been started (in particular the safe connection of a Linux installation to the digital cess-pool that is the Internet).  These notes may be of assistance to fellow Linux users, they may not.  For the most part they're wildly out-of-date (as you will see from the individual section dates), and simply mark the experiences gathered from early steps along a bumpy road.  These days the major Linux distributions are very much more mature, and most of these ancient scribbles are obsolete, and in many cases plain wrong.

Some sections - on the AST A41 or the Psion 5 series are of no practical user whatsoever, since the devices themselves are in the region of a decade obsolete and in the realms of the vintage.

October 10, 2009

  • Upgrading Linux versions
  • Internet issues
  • Linux on an AST A41 laptop
  • Infrared (IrDA) services
  • PCMCIA (or PC Card) services
  • SMB file services (Samba)
  • Connecting a Psion Series 5 to an IP network with Linux PPP
  • Logitech Quickcam Express (USB motion ccd camera)
  • 3Com Etherlink III cards
  • Knoppix - a Linux distribution runnable direct from CD
  • Projects past and present
  • Other useful places
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    Upgrading

    The network here consists of a number of different machines.  One of them, a dedicated Linux machine was recently upgraded from an old 8Mb 386, to 8Mb 486, and from Slackware 3.0 (kernel 1.2.13) to Slackware 3.4 (kernel 2.0.30).  This was then upgraded to kernel version 2.0.32.  The upgrade from Slackware 3.0 to 3.4 went smoothly enough, but what was irritating was the necessity to recreate the site dependent files which had previously been modified (some of the /etc/rc.d/rc.* startup files, /etc/hosts, /etc/profile, /etc/issue, /etc/motd, inetd.conf, inittab).  If you're doing a similar upgrade, remember to keep backup copies of any such files that you change, but don't then just substitute them back if they're configurations or scripts.  Doing that may cause you to lose details vital to the new system.

    One very particular annoyance was the change from Bind version 4.x in Slackware 3.0 to version 8.x in Slackware 3.4.  This is a very significant problem, because the configurations have completely changed.  Apparently there are some Perl scripts to convert between versions, but if Perl isn't installed (as in this case) it's a pain.  Solution: uninstall the Bind package using pkgtool, and reinstall the old from the Slackware 3.0 "N" disk set.

    One other thing that needs to be borne in mind is that apparently kernel version 2.0.30 is prone to some form of remote attack.  How, or what I don't know - I just took the advice I was given on trust, and installed the kernel source for 2.0.32 and upgraded (which if course requires the installation of the C compiler and appropriate system libraries - no hardship for me I install them initially as a matter of course).  If you're not a kernel person, read up on the process first, and MAKE SURE YOU'VE CREATED AN EMERGENCY BOOT FLOPPY FROM YOUR CURRENT WORKING KERNEL just in case everything goes belly-up.

    Kernels now in distribution are from the 2.2.x series (latest 2.2.18) and 2.4.x series (latest 2.4.2).  The main machines here are are all on at 2.2.18, except the oldest - a bodged-together '486 which remains at 2.2.5 because nothing later will compile, and I can't be bothered upgrading the whole installation.  At one point the laptop was still severely retarded, and stuck at 2.0.34 because of a hard-disk recognition problem, but that mysteriously went away again after some poking around with the compile configuration.

    March 25, 2001

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    Internet issues

    Blank - not because none to be had, but because it all needs some serious thought and ordering.

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    Linux on a laptop

    Another of the machines I installed linux on was an AST Ascentia A41 laptop machine.  Quite a nifty little machine.  In-built PCMCIA (2 slots), PS/2 compatible touchpad mouse driver, and Soundblaster compatible sound card with MPU 401 midi capablilty, too (Crystal CS4232 chipset).

    I originally installed Linux 1.2.13 (in the guise of Slackware 3.0) but very quickly hit problems with the APM and PCMCIA services so, having learnt from my lessons of upgrading to Slackware 3.4 on another machine, and taking the precautions noted above, did the same for the laptop (including the kernel upgrade from 2.0.30 to 2.0.32) which solved the basic difficulties.  Of course, since then the kernel has been further upgraded, and as mentioned above, is currently sitting at 2.2.18.

    March 25, 2001

    Infrared support (IrDA)

    Bluetooth wireless interfacing is just around the corner, but currently the commonest wire-free interconnection method is with infrared, predominantly to the standards set by the industry body known as the IrDA (Infrared Development Association?).  There is an officially affiliated project to support IrDA protocols and hardware standards within the Linux community (and as of kernel version 2.2.10, it has been supported at the driver level directly in the kernel).  The user-level utilities and kernel patches are in a constant state of forward development.  Up-to-date development information can be found on the Sourceforge project pages [http://sourceforge.net/projects/irda/].

    Latest source version is available directly via ftp [ftp://irda.sourceforge.net/pub/irda/].

    At one point I assisted Werner Heuser in updating the Linux Infrared HOWTO, by proof-reading and walk-through testing.  I'm still having immense problems getting IR services to do anything more than simply recognise the existence of another device.  Firstly I think I've pretty much established that libc5 libraries are no longer an option with IrDA, so I'm going to have to update to glibc (which is now considered the norm these days anyway).  More news as I make progress, which hopefully will be very soon...

    March 29, 2001

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    PCMCIA

    When it comes to the PCMCIA services, the service scripts they are kept up to date with the latest version of the card services, developed by David Hinds (nice one Dave!) at Stanford University.  As of writing, the latest version is 3.1.21 (as at October 2, 2000), available from the definitive source [ftp://projects.sourceforge.net/pub/pcmcia-cs], (moved from its original home at ftp://hyper.stanford.edu/pub/pcmcia) and from Sunsite mirrors, of which the UK choice would be Imperial College [ftp://sunsite.doc.ic.ac.uk/Mirrors/sourceforge.org/pcmcia] (formerly ftp://sunsite.doc.ic.ac.uk/packages/Linux/Extras/pcmcia/), except that this mirror doesn't seem to have kept up with the changing locations of the home source and is currently only mirroring sourcefourge.org which then redirects to the site at projects.sourceforge.net as detailed above.  (I have just notified the admins today, so hopefully I will be able to place a more useful link here once it is fixed.)

    My original installation of PCMCIA services was 2.9.6, when the machine was still installed with Slackware 3.0 (kernel 1.2.13, et al).  I had immense problems.  The card services first of all couldn't see the slot controller.  I tried to download and compile PCMCIA version 2.9.7 - compile errors left right and centre.  After a brief e-mail exchange on the linux-pcmcia mailing list (hosted at vger.rutgers.edu, along with several other linux related mailing lists) with David who said that 1.2.13 was "very old" and he wasn't in a position to test it, I bit the bullet and upgraded the core system, compiled again, and this time it all compiled and installed.  One word of warning: read the current documentation whenever you upgrade - the drivers sometimes merge or combine (mine did and I spent a long time wondering where I'd gone wrong because I hadn't read the docs, and still had an old driver configured into the setup).

    I now make a point of keeping the PCMCIA package up to date.  As with upgrading Linux, it's important when upgrading the PCMCIA services to keep any modified startup scripts for comparison.

    No disrespect to the author, but the supplied scripts are very rudimentary (no doubt deliberately so - relying on shell scripts provides a wonderfully flexible interface).  I use a network card on various sites, as well as at home and a PCMCIA modem when not at home.  With sensitive site specific detail removed, my modified PCMCIA control scripts are contained in the file pcmcia.tar.gz, comprised of the following files:

             shared       2875 bytes Nov 10 22:48
             network      6919 bytes Dec 23 13:01
             network.opt 3122 bytes Dec 21 02:53
             serial       2567 bytes Nov 10 03:37
             serial.opt   348 bytes Nov 10 02:11
      

    These files are modified from the package originals, to allow progress logging to one of the console virtual devices (or any other device for that matter), to switch configs for different IP setups (including different /etc/hosts etc. for various locations, setting up masquerading rules according to site, and specific routings), and switch pseudonymous devices (such as /dev/modem which alternates the PCMCIA modem when installed and the standard serial device otherwise).  My network config is such that whenever I use slot 0 for the network my home network is assumed, whilst slot 1 implies that I'm out on site, at a location specified as a name in a file.  It just so happens that this file is actually a symlink to a file on the Windows 95 partition for flexibility's sake.  (I have no access stats available for the site, so if you take a copy please do me the courtesy of dropping me a line.)

    The scripts should be used as inspiration for your own script files in the /etc/pcmcia directory.  These are not files that should be fiddled with lightly.  Be sure that you know what you are doing before you dive in and tinker.  I certainly accept no responsibility for any consequences of using these files, either whole or in part.

    October 14, 2000

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    Windows SMB file services (Samba)

    Another segment awaiting construction.

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    Connecting a Psion Series 5 to an IP network with Linux PPP

    The Psion Series 5 EPOC-based PDA comes, in addition to the standard utility applications already installed (Word, Sheet, Data, Agenda, etc...), with PsiWIN and a bundled install for an e-mail client and web browser included in which is a simple IP stack and PPP layer.  It's not immediately obvious, but in fact the PPP can be configured to run a direct connection (once the web/e-mail bundle is upgraded to version 1.50 or better - currently 1.52) without assuming the need to dial a modem.

    I'll get around to writing a proper description sooner or later [very MUCH later, given that it's now 5 years on and I haven't made any significant additions to any of this in that time], but for the moment, all I present here (as guidance to the already sufficiently competent) are the contents of the appropriate peer file (/etc/ppp/peers/psion5), with particular local network specific details suitably obscured:

          <server.ip>:<psion.ip>
          allow-ip <local.net.address>/<local.net.mask>
          local
          debug
          passive
          proxyarp
          ipcp-accept-remote
          ms-dns <local.primary.dns>
          ms-dns <local.secondary.dns>
          noauth
      

    The ppp command line in /etc/inittab which this peer file is the accompaniment to is:

             p1:12345:respawn:/usr/sbin/pppd /dev/ttyS1 38400 nodetach call psion5
      
    Consult man pppd or other documentation to dissect this command.

    NB: The command above explicitly allows ANY ip claiming to be on the local net without authentication.  As yet I haven't persuaded PAP authentication to work over the null modem link.  Note also that by placing the pppd command in /etc/inittab PPP is permanently running on the serial port in question.  All other processes normally respawned for that serial port (ordinarily some form of getty process) must be disabled.

    There is a package called PLPtools which substitutes for the Windoze support software supplied by Psion (imaginatively called PsiWin).  PLPtools allows the Psion, by devious means, to be mounted directly on the Linux server as an NFS mount.  The current release is version 0.6.  Unfortunately, I can't for the life of me get it to compile, added to which there is the complication that it seems to be directly targetted at a Red Hat distribution, which confuses matters on my Slackware installed boxen.  Up-to-date development information can be found on the Sourceforge project pages. [http://sourceforge.net/projects/plptools/]

    More (much more) to come...

    March 29, 2001

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    Logitech Quickcam Express (USB video camera)

    Some while ago I bought a Logitech Quickcam Express - a webcam for USB - with the intention of playing around a bit with some webcam stuff.  I should have done my research first because I would have saved myself the heartache of discovering, after buying it, that Logitech are a bunch of arsewipes and are refusing to co-operate with the Linux community by releasing the necessary specs to develop Linux support.

    It's now a year on, give or take, and people better equipped than me have reverse-engineered the protocols for one chipset in use in the cameras.  Investigation of the alternate chipset also in use is yet to be completed.  (See the links below).

    January 11, 2006

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    3Com Etherlink III network interface cards

    Network cards, these days, tend to be software configurable.  Unfortunately, the manufacturers seem - on the whole - to assume a Microsoft-crippled system and supply only MS-DOS or Win[9x,NT,2000] executable configuration tools.

    Recently, I had a requirement to change the interface port on a 3Com 3c509 network card from 10base2 (i.e. thin co-ax) to 10baseT (cat 5 twisted pair).  All of the available documentation that popped up in search engine searches suggested that the only way was to use 3Com's distributed setup tools (DOS executables), which would have been distinctly tedious, requiring extricating the machine in question from its happay abode, and finding it a keyboard and monitor for the duration.  Thankfully a newsgroup posting asking for assistance led to a simple setup program called (unsurprisingly) 3c5x9setup, which can be found in source form at http://www.scyld.com/diag/3c5x9setup.html.  It does the job beautifully.  It even made the change on a live machine, over a telnet session, without breaking anything.  Who says open source is unprofessional?

    There seems to be a derivative work at http://programs.mini.dhs.org/Current/3c5x9setup/, but which doesn't seem to derive from the latest version of the original.  Furthermore whilst I can vouch for the efficacy of the original author's program, I can't make any representations about this one.

    December 3, 2000

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    Knoppix

    Knoppix has proven to be a very useful tool, providing a live-running Linux system straight off CD.  This is a useful tool, not just for running Linux on a machine on which a full installation is not practical, but also as a meants of safely recovering valuable material from a compromised Windows machine.  It also serves as a useful demonstration of the power and flexibility of Linux to interested novices.

    January 11, 2006

    Projects past and present

    Some of the notes on the projects - in the sense of tasks and goals I have set myself over the years - have now been moved to a separate page, covering such things as Fedora, a webcam and motion detection, an external 250Mb Zip drive, incorporating a Psion 5 and a 5MX into the home network, time synchronising with NTP and the Rugby MSF clock, and custom fortune cookie files.

    January 11, 2006

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    Other sites

    And here are some links to resources I've found helpful or interesting in my tinkering:

    November 30, 2005

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    This page and all subordinate pages and the information and information content authored by, and Copyright © 1997, 1998, 1999 & 2000 of Gulraj Rijhwani and Courtfields unless otherwise specified.


    For further information contact:

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