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SubjectRe: 16 MB -> 32 MB, a memory problem resolved!

Andrew E. Mileski wrote:
> Some motherboards can relocate the 384k RAM that is leftover
> from making the I/O hole at 0xa0000-0xfffff, but most can't.
> What is worse, this feature _ONLY_ works with 16Mb or _LESS_
> installed memory (on most mobos).
> ...
> Linux can't read your mobo manual for you (or the mind of the
> mobo designer). For that matter, no OS can (especially not Windows).

I believe SCO's "boot" program does some memory probing before loading
the kernel - passing a map of memory type/usage in page 0. (I think it
also performs a basic memory read/write test for early trapping of
mis-configured systems). I don't know how the detection works - it
maybe only be for some BIOS/Bus archs.

Isn't it possible to look for BIOS signatures between 0xa0000-0xfffff
(check every 2k?) to determine what memory is left for the OS?
Other reserved areas (such as floppy track buffer, VGA fonts) are at
well know addresses. The interesting problem is detecting the onboard
memory in other cards...


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