From: George Caswell (tetsujin_at_maine.rr.com)
Date: Thu May 25 2000 - 01:48:27 EDT
On Tue, 23 May 2000, Shawn T. Rutledge wrote:
> Well I don't have any problem with a DOS based loader... it might
> even be a good idea on that kind of machine so I can run a few
> (gasp) DOS programs too. And I've heard that those disks aren't
> straightforward to get a FAT filesystem installed from scratch either.
> It might be better to use fips to shrink the existing partition to
> make room for an EXT2 partition. But that's a hunch at this point.
> My attempts to date have been with the kind of Linux distro that just
> runs off a FAT partition, not because that's particularly good but
> because I didn't want to push my luck just yet.
It's actually not all that hard to start from scratch if the drive
filesystems or partitions get messed up. Under Linux, you just insert the
drive, fdisk and mkfs as necessary.
Getting a PCMCIA drive bootable (with a DOS bootsector and OS) can be a bit
more of a challenge. Usually what I do is either install the drive into a
working MS-Windows machine and run sys from there, or access the partition in
DOSEMU.
The hardest challenge I've come across as far as putting data on the drive
was re-installing a DOS master boot record after my ill-fated attempt to run
LILO from the drive. Windows wouldn't do it for me, don't know how to do it
directly from Linux - ultimately had to get an older version of DOSEMU (0.66
or so - supporting "wholedisk"), boot DOSEMU from a floppy/floppy image, and
fdisk/mbr that way. For some reason, tho, the DOSEMU folks took wholedisk
support out of DOSEMU 1.0... <grumble>
But as for distros - I'm still not that far along yet. I'm really stuck on
this bootup thing. If I can at least get cardmgr to run and beep at me, so I
know it found the hard drive, then the rest of the installation is easy. I
hope the Thinkpad doesn't do something stupid like hide the PCMCIA device that
it's masquerading as a regular IDE controller.
> > So I'm thinking my next attempts are gonna be along these lines -
> > super-streamlined kernel, everything in modules except for the vitals - initrd
> > and the filesystems. initrd image will run card services (which will
> > hopefully find the drive, install the module, and allow me to boot) - from
> > there, a regular root volume setup.
>
> Yikes how do you even switch the root filesystem from the RAM disk to
> the hard disk? Can that be done? If you keep the RAM disk and try
> to mount the hard disk on top of it, you'd have a whole bunch of mount
> points for the directories under root, right? Unless you can find the
The technique is called initrd - the driver is included probably at least
as far back as 2.0. It's just an automated mechanism for taking a filesystem
in RAM (loaded by the bootloader) and running a program there - when that
program is done, the real root partition is mounted and the ram disk is
remounted to /initrd. You just make a filesystem with the drivers and
programs you need, put it into your bootloader, and the initrd driver
automates the rest.
At least, that's how it's supposed to work. Like I said, I haven't been
able to get one to run. On the other hand, I've gotten lots of them to fail
to run. But the mechanism is there, intended for various situations where
essential drivers had to be loaded in before root got mounted - SCSI drivers,
PCMCIA, etc. Actually to be more precise, I believe I have gotten one initrd
rootdisk to run, it just didn't do much. I seem to be having no luck even
getting a shell going.
> > For a bootloader, one version of DOS or another calling straight into
> > loadlin. Since on startup the kernel image and initrd image will have to be
> > in memory at the same time keeping it all small enough for the 8MB is key.
>
> Well you can upgrade the memory. 8 meg and larger 5V DRAM cards show
> up on ebay now and then. I got a couple of them.
Hee hee... I think I spend far too much money on EBay already. :) As for
the other stuff, it turns out DOS makes a pretty decent bootloader - and main
memory isn't such a huge problem as I thought, if you really strip it down
even a 2.3.99 can fit under a half meg zImage... the initrd is more of a
problem space wise...
> > I'd love to hear if anybody has any useful input on this - and also whether
> > BSD might be better equipped to run on this neat little machine.
>
> That's a very good point; maybe its IDE driver is more universal.
>
It's also possible their PCMCIA support is better. At least that's what
I'm hoping. This would be so much easier if I had my school Linux club to
turn to for help.
> BTW I would be most grateful if you help flesh out the Wiki at
> http://cx47646-a.phnx1.az.home.com:9673/zwiki/SlateComputers/ThinkPad%20730T
> (which is reachable by clicking the link at
> http://www.bigfoot.com/~ecloud/730T/ )
>
The link doesn't seem to work. It just hangs.
---GEC
Projects page: http://tetsujin.sourceforge.net/
GAIM/AOL IM: Tetsujin0 - Message anytime -- ICQ: 46909656 - I never use it
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