[NTLUG:Discuss] Breathing life into a really ancient laptop.

[Steve Baker]

(A long story - leading to a hopefully easy question)

I've been thinking of putting a small computer into the dashboard of
my car to read out a bunch of engine parameters in realtime from the
car's diagnostic port (OBD-II).  I have an interface gadget to connect
the OBD-II port on the car to a regular serial port - and the 'freediag'
project will form the basis of the interface software.

My wife is kinda sick of the amount of money I'm sinking into this
car - so I'm trying to do this for approximately $0.00, which means
that I have to use old hardware that I already own.

Fortunately, I have an ancient laptop that's been sitting in a closet
somewhere for about the last 6 or 7 years.  It's a 25MHz '486
Compaq Aero with 4Mb RAM and 80Mb of disk.  It's perfect for the
job because it has a small display and a tiny keyboard with an
integral track-ball - and it seems happy to run off a voltage
regulator from the 12v outlet in my car instead of it's
internal battery.

The huge problem is that it's running Windows 3.1 - and that simply
won't do...but installing Linux on it is something of a challenge
because it's external floppy drive has 'died'.  That (and the fact
that the battery is shot) was the reason it was consigned to the back
of the closet in the first place.  The external floppy has some really
weird Compaq-specific interface and I can't get a replacement. It
doesn't have a CD-ROM drive or any kind of network interface.

The only usable routes into the box are the parallel port and the
serial port.  So my plan is to load a stripped down copy of
Slackware'96 via the serial port using Kermit and the Windoze
Terminal program.  Without X-windows (which I don't need), Slakware
claims to fit in 4Mb RAM and 20Mb disk.

With Windoze stripped down fairly aggressively, I figure I'll have
maybe 60Mb of disk space.  Once it's all running Linux nicely, I
can trash the Windoze partition and have plenty of space for adding
my own code.   However, I have to be pretty careful because until
Linux is running, trashing the Windoze partition will turn this
machine into a paper-weight.  (Remember - no floppy drive!)

I've managed to use LOADLIN.EXE under DOS to start a UMSDOS kernel
and load a root partition into a RAM disk.  In theory, I can use that
to run the fdisk program to repartition the hard drive and move programs
from the DOS partition into the new Linux partition.

However, during the boot process, it asks you to enter a swap-space
size and claims it's going to create it in a file called:

     C:\LINUX\DEV\SWAPSPACE

- which it seems to do because it's visible from DOS.  The problem
is that as it does that, it outputs a bunch of error messages that
scroll past too fast to read, and I can't find any kind of log file
where they might have been recorded.

I do get a login: prompt and can log in as root - but when I try to
do the next step and run fdisk, I get bunches of nasty errors and a
crash back to the shell prompt.

Does anyone remember Slakware'96 well enough to have a clue what
might be going wrong...or at least where to find some kind of error
log?

Mechanically, I plan to fold the laptop's electronics back behind the
display panel and replace the flexi-cable that connects to the
keyboard with something longer and easier to route somewhere.  I'm
going to control the software with custom buttons hung from the parallel
port - the keyboard will only be plugged in for maintenance.  The dead
battery is already history - so all I really have behind the display
is one circuit board and the hard drive.

The graphics will have to be driven with custom software because there
won't be enough RAM to run X - but that's OK, I can cope with that.

---------------------------- Steve Baker -------------------------
HomeEmail: <sjbaker1 at airmail.net>    WorkEmail: <sjbaker at link.com>
HomePage : http://www.sjbaker.org
Projects : http://plib.sf.net    http://tuxaqfh.sf.net
            http://tuxkart.sf.net http://prettypoly.sf.net
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