Re: Reproducable hard locks in 2.2.17. IDE related

From: Andries Brouwer (aeb@veritas.com)
Date: Fri Sep 22 2000 - 06:51:20 EST


On Fri, Sep 22, 2000 at 02:34:16PM +0200, Igmar Palsenberg wrote:

> It could be that it is choking on the fact that one drives is LBA, one
> drive isn't. Drives are identical, but dmesg gives different CHS for each
> of them..

A FAQ. See
        http://www.win.tue.nl/~aeb/linux/Large-Disk-14.html#ss14.2
("Nonproblem: Identical disks have different geometry?")

Furthermore, it seems there is a misunderstanding here.
"One drive is LBA, the other isnt" is nonsense.

(There are two access methods to disks, sometimes called CHS and LBA
access. These days all disks are capable of handling LBA, and Linux
always uses LBA.
There are zillions of geometry invention, distortion and translation
methods, a few thousand of which are called LBA. Such geometry business
is completely unrelated to Linux disk access.
You seem to confuse the former LBA with the latter.)

> hda: Maxtor 71626 AP, 1554MB w/128kB Cache, CHS=789/64/63, DMA
> hdb: Maxtor 91021U2, 9641MB w/512kB Cache, CHS=1229/255/63, (U)DMA
> hdc: Maxtor 91021U2, 9641MB w/512kB Cache, CHS=19590/16/63, (U)DMA

Here 1.4 MB is wasted on hdb because the BIOS has invented
this 1229/255/63 translation. The disk access methods on
hdb and hdc is the same.

Andries

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