Hi!
18-Апр-2004 19:15 [EMAIL PROTECTED] (Eric Auer) wrote to
[EMAIL PROTECTED]:
EA> Hi, while MS Win98 MEM could be called a "standard", I do not agree with:
>> b7ff 81920 DOS system code
>> 9fff 65536 DOS system code
EA> Those are video buffers - even if the MCBs mark them as excluded / system
EA> code or similar, a note would definitely not hurt. For example:
EA> b7ff 81920 DOS system (excluded area)
This is _not_ excluded area, this is MCB, which marked as system (with
`owner' equal to 8. And there are no explicit ways to detect what contained
inside these blocks, you may only suggest that there resides (or not) video
memory or ROMs.
EA> Especially the 9fff 64k sized area (well, MCB is at 9fff, but area is at
EA> a000, which is confusing but again MS "sets the standard")
This is because there shown area, as it starts from MCB, not _after_
MCB, whereas video memory comes after MCB.
EA> could even be recognized as a very particular area:
EA> 9fff 65536 DOS system (excluded: EGA/VGA video buffer)
EA> or something like that.
This is not necessarily. There is possible to reuse video memory as
plain memory (for example, with help of VIDRAM from QEMM package), and this
memory is not necessarily will be joned as "plain" MCB with previous MCB
(as this does VIDRAM:
08E2 1760 VIDRAM =C:\QEMM\VIDRAM.COM
0950 1680 NDOS =NDOS
09B9 681056 --free--
-------
AFFF 5008 <system>
B138 224 DOS-UP
).
>> 0269 2048 EBDA data area
EA> Is it actually useful to move the EBDA there? As far as I remember it does
EA> usually allocate memory by reducing the 40:13 value to something below 640.
EA> Both locations are inside low DOS memory. Maybe relocation helps because
EA> DOS can allocate in 16byte units while BIOS 40:13 uses 1024byte units?
EBDA may be relocated to UMB. At least, QEMM does this. Also, placing
something between two memory blocks prevents to join these memory blocks
(and, thus, you can't expand low memory area by VGA video memory).
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