Help(!) with Slink install -- disk repartitioning problem

[Christopher Lee <robodoc@mediaone.net>]

*cc me on any replys, since I am not subscribed to debian-user*

Please read this if you know something about hard-disk partitioning,
and think you can tell us where the "mystery 2 Gigs" went.  My wife is
a little stressed-out that I may be messing-up her computer....

I'm installing Slink on my wife's laptop (I have the CDs lying around,
and will upgrade it to Potato later).  She has a HP Omnibook 4150
Laptop with a 10Gig HD running Windows 95, which I am modifying to
work as a dual-boot machine.

We used fips to shrink the DOS partition to 6 Gigs, and booted off the
Slink CD to install Debian.  When we got to the disk repartitioning
step of the install, cfdisk complained that the hard drive had
inconsistent partition information and wouldn't run.  Undaunted (maybe
stupidly), I shelled-out from the install program and ran ordinary
fdisk, and removed the new partition that fips had split off from the
original DOS partition.  After this, cfdisk ran, but it reported that
we only had a little less than 2 Gigs left on the disk -- since it is
a 10Gig drive, and we left 6 Gigs for Win95, we thought we should have
4 Gigs for Linux, not 2Gigs.

We went into the BIOS setup, and checked the disk information from
there.  Here is what it reported about the drive:

	Cylinders	 17475
	Heads		    15
	Sectors		    63
	Max Capacity	  8455 MB

	   LBA Format

	Total Sectors	19640880
	Max Capacity     10056 MB

        Multi-sector transfers  16 sector
        LBA mode control        Enabled
        32 Bit I/O              Disabled
        Transfer mode           Fast PI0 4
        Ultra DMA mode          mode 2

I don't know much about hard drives, and don't really know what LBA
is, but the apparent loss of disk capacity seems somewhat similar to
the difference in capacity between the two "Max Capacity" lines
listed.  Is the second capacity somehow illusory, or available to DOS
but not Linux?

After I set up partitions for Linux to use as much disk as fdisk would
let me, fdisk reports the following:

        Disk 240 heads, 63 sectors, 1024 cylinders
        Units = cylinders of 15120 x 512 bytes

        Device    Boot  Start  End  Blocks  ID  Sys
        /dev/hda1   *     38   824  594XXXX  c  Win95 FAT32 (LBA)
        /dev/hda2          1    37   28XXXX a0  Unknown [laptop suspend part.]
        /dev/hda3        825   842   136080 82  Linux Swap
        /dev/hda4        843  1024  137XXXX 93  Linux native

        [X's fill in the digits I didn't copy to my notepad]

Note that the disk geometry is totally different than what was listed
from the BIOS -- I don't know if this is meaningful, or related to the
apparently-missing disk space.  Does fdisk always assume a maximum of
1024 cylinders?  Should I use the expert mode of fdisk to manually
supply the disk geometry information from the BIOS and then re-make
the Linux partitions, or will this totally destroy the data currently
on the disk (in the Win95 partition)?

If you can help us better understand what this all means and how we
might fix things, please reply and cc to me directly since I am not on
this list.  Should we get PartitionMagic to straighten this out?

Thanks in advance,
 - Chris

-- 
Christopher Lee (robodoc@mediaone.net or chlee@mit.edu)
http://www.cs.cmu.edu/~chrislee