hdd-kernel-parameters & hdd-geometry

hdd-kernel-parameters & hdd-geometry

Post by K. Poser » Wed, 23 Aug 2000 09:54:30


First of all a simple question: Do I have to pass the *physical* or the
*logical* geometry with the "hdc=X,Y,Z" - kernel - parameter?
I think I have to use the *logical* geometry... but what about the
phyiscal one? - Can I tell the kernel somehow about them?

Now about my hdd:

I've got a harddisc with the following geometry:

The manufacturer (IBM) says in the models datasheeet:
    User cylinders (physical): 27724
    Data heads (physical): 6
    Data disks: 3

On the harddisk itself I found the following:
    LBA: 90 069 840 sectors

And 90069840 / (16*63) = 89355

If I pass "hdc=16383,16,63" with "append=" in the lilo.conf to my 2.2.14
kernel a "cat /proc/ide/hdc/geometry" says:
    physical geometry: 89355,16,63
    logical geometry: 16383,16,63

And if I pass "hdc=89355,255,63" with "append=" in the lilo.conf to my
2.2.14-kernel the "cat /proc/ide/hdc/geometry"-command says:
    physical geometry: 89355,16,63
    logical geometry: 89355,255,63

But I think it should look like:
    physical geometry: 16383,16,63
    logical geometry: 89355,255,63     OR (???)    89355,16,63    ???

So what (which values) do I have to pass to the kernel?


Oh... and my BIOS is only capable in handling harddiscs <= 8,4 GB and
there is no further Bios-update available.
And the harddisc I spoke about is regocnized as a 8,4 GB harddisc with
255 heads and 1027 cylinders.

Should I let the BIOS detect the harddisc or should I enter "None" in
the BIOS-setup instead?

And should I pass "hdc=noprobe" to the kernel or not?

I am a bit confused about all this stuff with all these numbers...

Help on this would be great!

Kind regards

K. Posern


1. Weird HDD geometry & RH5.0

The problem is that, partway through the package install, the machine
The major symptoms are that the progress bar stops dead; the HDD LED
goes on and stays on while the CD is no longer accessed; it is possible
to switch tty's but they don't respond to input.

I suspect that the problem is that the setup program thinks the drive is
C/H/S: 527/64/63 when the BIOS tells me that it is 2111/16/63. The first
time I attempted to install I used Disk Druid and let it do it's thing,
and it froze at 60% complete. The second, I used fdisk to change the
number of C and H, but it complained that hda1 & hda2 overlapped with
hda1 being sectors 1..2045 and hda2 being 2046..2111. The 'format swap'
step also thought that the drive was C:527. What the heck, I tried the
install anyway--it froze at 10%.

I've tried using Partition Magic on the hope that it would detect the
geometry properly, but the results were the same as before.

I tried using the Slackware boot/root disks I have lying around to
partition and format the drive, and the only change is that, after the
install freezes, the tty's still accept input.

This machine just recently had win95 running on it fine, so I know it
_can_ work. What am I doing wrong? What can I do to force the setup
program to recognize the drive properly? Anybody run into this problem
before? The book that the disc came with mentiones that if Disk Druid
detects the drive incorrectly, that fdisk must be used, but it hasn't
fared any better, as I said. I don't think fdisk is the problem though,
I think the setup is trying too hard to write with a head that isn't

I'm at the end of my resources. The only alternative to making RH work
is win9x. Help!

System vitals:
Intel P90, 16Mb RAM, 1.0Gb HDD, 8x Tatung CDROM, AMIBIOS ver
1.00.02.BS0, RH 5.0

Respond by mail (wyrmbait_at_softhome.net) SVP.

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