[Qemu-devel] Re: BIOS behaves different as real BIOS

[Ben Pfaff]

"Natalia Portillo" <address@hidden> writes:

> I think that this is because the BIOS searches for the 0x55AA signature on
> last two bytes of first sector of disk.
> As far as I remember, this signature was introduced very lately and as far
> as I tested on my real systems, this signature is not really searched at
> boot time, and every DOS before 3.0 doesn't have it (it is used also by
> later DOSes and Windows to identify a FAT filesystem), at least on floppies

You can disable the signature check by setting byte 0x38 in the
CMOS RAM to a nonzero value.
-- 
"...In the UNIX world, people tend to interpret `non-technical user'
 as meaning someone who's only ever written one device driver."
--Daniel Pead