On Apr 3, 12:34 am, junkoi <spamt...@[EMAIL PROTECTED]
> wrote:
> Hi,
>
> I am wondering if my option ROM can use Extended BIOS Data Area (EBDA)
> to store some (very) small data (around 16bytes)? Which area in EBDA
> is safe and guaranteed for my option ROM?
>
> Do anybody know any updated documentation about EBDA?
>
> Thanks,
> J
I don't know of any 'up to date' documentation. The EBDA originated
with the IBM PS/2 line, in their bios, from what I've gathered, and
like many things IBM started, it got incor****ated into other bios's,
like Phoenix's, if you have a PS/2 type mouse then your system likely
sup****ts it. The segment of the EBDA is found at 40:000Eh, and the
amount of 'conventional' memory returned by int12h should be A000:0h
minus sizeof EBDA. It is an additional scratch area whose fields are
ill defined and seem to be OEM bios specific. It holds fields for the
mouse driver and mouse state, those are the most consistant, and other
fields used for the bios's benefit. Originally, for the PS/2 line,
it's main purpose beyond the mouse was to hold information about the
hard drive geometry.
I would like to know if it is still present on the latest systems with
their USB everything, anybody know?
#dw40:0e
0040:000E 9FC0 C823 80F0 0002 2000 0000 002C 002C ..#...... ..,.,.
9FC0:0000h is correct for this system.
Steve
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