History
The first DPMI specification drafts were published in 1989. Version 0.9 was published in 1990 by the DPMI Committee, and it was again extended in 1991 with version 1.0. An additional feature called "True DPMI" or "DOS API translation" was proposed by Ralph Lipe in the version 0.9 drafts, but never became part of the official specification (even not with 1.0); nevertheless, Windows implements this undocumented "True DPMI" nature. The official DPMI specification is available from Intel Literature Sales as well as online.
Note that the DPMI "method" is specific to MS-DOS and the IBM-PC. Other computer types were upgraded from 16-bit to 32-bit, and the advanced program support was provided by upgrading the operating system with a new 32 bit "API" and new memory management/addressing capabilities. For example, the OS/2 core system supports 32-bit programs, and can be run without the GUI. The DPMI solution appears to be mainly needed to address third party need to get DOS protected mode programs running stably on Windows 3.x before the dominant operating system vendor, Microsoft, could or would address the future of 32-bit Windows. In addition, Microsoft didn't see the answer to the 32-bit transition as a 32-bit DOS, but rather a 32-bit Windows with a completely different (and incompatible) API.
DPMI is tailored to run extended DOS application software in protected mode and extended memory, but it is not particularly well suited for resident system extensions. Another specification named DPMS specifically addresses requirements to easily relocate modified DOS driver software into extended memory and run them in protected mode, thereby reducing their conventional memory footprint downto small stubs.
Read more about this topic: DOS Protected Mode Interface
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