Subject: Re: unbootable new disk?
To: Robert Nestor <email@example.com>
From: David Laight <firstname.lastname@example.org>
Date: 11/27/2004 09:21:03
> Based on the wording of the "137Gig Limit" that came with this disk,
> what I was able to find on the subject online from various disk
> manufacturers and what I saw with two different disks on this system, I
> suspect the 137Gig limitation is partially a BIOS problem and partially
> an OS problem.
The root cause is that no one ever believed disks would get that big!
The ATA/IDE specification only has 28 bits available to pass the sector
number to the drive - which limits you to 137GB.
To read beyond that point you need to use LBA48 transfers (which basically
involve the sector registers being treated as a 2 deep fifo and you writing
two byte values to each register - then execting a different command byte).
This is only the latest (and probably not the last!) size limit on IDE disks!
A web search will give you most of them....
David Laight: email@example.com