Linux: TP755CE (810MB disk) partial success [and QUESTIONS!]

[Chet Murthy <chet@watson.ibm.com>]

[A description of what I did, with a could of caveats marked with
"NOTE WELL".  Followed by some questions, for the wise.]

Hi,

I finally got Linux to install on my TP755, and I thought I'd share my
experience, so that other could avoid spending several days at it.

(0) My machine is a TP755CE, 8MB mem, 810MB disk, 2.88MB floppy.

(1) I started with the Slackware 3.0 distribution, and found that,
while I could get my Thinkpad to read the boot diskette, I could not,
for the life of me, get it to read the root diskette -- it
consistently complained about a read failure.

(2) So I hunted around, and found the "minilinux" distribution -- a
Linux which fits onto 4 floppy disks and unzips into your ms-dos
filesystem.

(3) I unpacked it, and fired it up.  No sweat.  Then I verified that I
could indeed read the root floppy, by mounting it onto my machine on
/dev/fd0.  Again, no sweat.

(4) Using the kernel in this distribution, I modified the "linux.bat"
boot file and used it to boot the installation root-disk.  Note that I
did *not* use the installation *boot*-disk.

(5) I installed as normal.  However, there was *one* quirk.  As others
have related, the 810MB disk is a 784-cylinder, 32-head, 63-sector,
disk.  To boot the kernel for installation, though, you have to tell
it:

   hd=1571,16,63 floppy=thinkpad

[I also added "aha152x=0x340,11,7,1" for my Thinkpad Dock II SCSI
CDROM]

But when you now go and use Linux FDISK to partition your disk and set
it up for Linux filesystem and swap, if you do a "v" (verify), it will
complain *vociferously* about the partition table being inconsistent.
The problem is that FDISK is using the current disk geometry, which
you just set above to an erroneous value (since the disk has 32 heads,
as you can verify if you use dparam.com (which you can find in the
LILO distribution).

SOOOOOO.... The right way to do this is ... fire up fdisk, and *before*
partitioning, do:

(a) drop into expert mode (x RET)
(b) set the number of heads to 32 (h RET 32 RET)
(c) set the number of cylinders to 784 (c RET 784 RET)
(d) return to normal mode (r RET)
(e) now partition away !

(6) Now you can install Linux, but [NOTE WELL] do *NOT* install LILO
on the Master Boot Record (MBR) of your disk.  Put LILO onto the
boot-record of the Linux Filesystem partition you created.  You will need
to specify the same options that you did for booting the installation
diskettes -- i.e., a *fake* disk geometry.  You will find that LILO
does *not* boot correctly.  You will need to edit /etc/lilo.conf, and
add lines like:

disk = /dev/hda
  heads = 32
  sectors = 63
  cylinders = 784

(and then rerun "lilo") in order to get a bootable system.

----------------------------------------------------------------

OK.  Enough of my description.  The key point that I found was this:

   I could *not* read from the floppy drive with the Slackware 3.0
   kernels.  Not *one* of the boot-disks that I tried worked, nor
   did the installed kernel.

   The MINI-LINUX kernel, on the other hand, reads from the floppy
   just *fine*.  I don't konw what's going on -- does anybody have
   any idea?

Thanks in advance,
--chet--