Re: 10.2 Gig HDD

Ben Hutchings (womble@zzumbouk.demon.co.uk)
Sat, 23 Jan 1999 00:05:52 +0000


On Thu, Jan 21, 1999 at 04:58:28PM +0100, Max wrote:
<snip>
> Now, IDE disks can have at most 16 *physical* heads. If you tell the kernel
> that the geometry of your disk is 787/128/63 (as with my 3G Western Digital)
> the kernel will use the *physical* geometry 6296/16/63 for C/H/S addressing
> (it's deduced from the logical geometry you specify, knowing Heads<=16)
> or will use LBA, knowing that the disk has 6346368 sectors (approx 3GB).
<snip>

The `physical geometry' is no more real than the `logical geometry' -
it's just the drive's lies rather than the BIOS's lies.

Today's hard drives divide the disk surface into concentric zones with
differing numbers of sectors-per-track. This is hardly a new trick,
but it still makes it impossible to describe the geometry in C/H/S
terms even without the stupid limitations on those numbers.

-- 
Ben Hutchings, software engineer | web site to be reconstructed at some time
womble@ferret.lmh.ox.ac.uk | Team *AMIGA* | Jay Miner Society - www.jms.org
Absolutum obsoletum. (If it works, it's out of date.) - Stafford Beer

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