RE: Wierd IDE configuration

Guest section DW (dwguest@win.tue.nl)
Tue, 20 Apr 1999 21:21:44 +0200 (MET DST)


From: BROWN Nick <Nick.BROWN@coe.fr>

> > hda: IBM-DTTA-351010, 9671MB w/466kB Cache, CHS=1232/255/63,
UDMA
> > hdb: IBM-DTTA-351680, 16124MB w/462kB Cache, CHS=2055/255/63,
UDMA
> > hdc: IBM-DTTA-351680, 16124MB w/462kB Cache, CHS=32760/16/63,
UDMA

Maybe I'm getting over-confident here, but it seems like this could also be
explained by probe_cmos_for_drives(). The setup.S code reads the BIOS FDP
table data for the first two drives only,

Yes. That is precisely what happens.

so it will have older-style (loads of heads, fewer cylinders) numbers
for hda and hdb. On the other hand, subsequent drives can only be found
via the more modern methods in do_identify().

s/older-style/BIOS-translated/
s/hda and hdb/whatever disks have BIOS numbers 0x80 and 0x81/
s/can only be/are only/
s/more modern//

A couple of tests you could do:
- if hdc has been formatted by a non-Linux program, see if fdisk complains
about its partitioning (BIOS format not matching drive format)
- swap hda and hdc. My guess is that the two 16GB drives will appear
identical, and that the 10GB drive will appear to have about 19630
cylinders.

Yes. Although testing is rather superfluous - the situation is perfectly clear.

s/about 19630/19650/
(it looks like over 7MB is wasted because of the BIOS LBA translation;
maybe the disk has a size of 10141286400 bytes, of which only
10133544960 are used at present)

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