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Friday, March 22, 2013

DOS Protected Mode Interface (DPMI)

DPMI is outdated by today's standard of course. However, in certain situation it comes handy. I've been looking for documents/standards/specifications from my early days of BIOS reversing that could explain most of the 32-bit code I'd seen on the BIOS.

One of the most intriguing terms were the memory related terms, e.g. high memory, upper memory, etc. I came to think that there were no standard(s) at all which govern the use of the term. However, upon reading the DPMI specification, I finally realize that the "gaps" (in my knowledge) between the 16-bit code and 32-bit code on the BIOS are covered by the DPMI specification. Well, not all of them of course because there are still the voodoo mode. But, nonetheless, a large fraction of the missing link is in the DPMI.

For those interested on the spec. This is the link: http://homer.rice.edu/~sandmann/cwsdpmi/dpmispec1.pdf.

Have a nice weekend :-)
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2 comments:

Anonymous said...

don't forget VCPI that predates DPMI https://student.brighton.ac.uk/burks/pcinfo/progdocs/vcpi.htm

Darmawan Salihun said...

Thanks for that. I've never knew about VCPI before.