On Sat, Jan 12, 2002 at 10:48:06AM -0000, David Laight wrote:
> Ah those horrid Compaq disks.....  I gave up on an external disk
> cabinet on an old compaq proliant server and bunged a disk onto
> the internal scsi channel.  We were only doing OS testing and 
> needed a multi-cpu system (didn't need all that disk rack space).
> 
> In any case:
> Error '3' means it failed to find 0xaa55 in the last word of the
> sector it read from the disk.  This is the only sanity check it
> does on the read sector before executing the code from it.
> 
> You might have a BIOS that doesn't like LBA disk reads?
> The bootselect code doesn't have the space to do as much LBA/CHS
> checking as the the other bootstraps.
> 
> If does have an option (settable by fdisk) to use CHS reads instead
> of LBA ones.  But I don't recall seeing the code in fdisk to set it.
> Set the byte (maybe offset 0x195) that enables the bootselector to 0x03.

Each time I got this error it was a geometry problem. A bootable (fdisk)
partition much start on a cylinder boundary, for the BIOS gemetry.
fdisk should output something like:
2: sysid 169 (NetBSD)
    start 7968240, size 8466255 (4133 MB), flag 0x80
	    beg: cylinder  496, head   0, sector  1
	    end: cylinder 1022, head 254, sector 63

That is: "beg" should always show "head   0, sector  1".
Also make sure beg/end matches the geometry used by the BIOS.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
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