| Dpmi |
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Information AboutDpmi |
| CATEGORIES ABOUT DOS PROTECTED MODE INTERFACE | |
| x86 memory management | |
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The DPMI specification version 0.9 was published in 1990 by the DPMI Committee, and it was extended to version 1.0 in 1991 . It is available from Intel Literature Sales. However, version 1.0 was never implemented in Windows so programs have to be written to version 0.9. VCPI VCPI (Virtual Control Program Interface) was an earlier and incompatible method for doing the same thing. It was limited to 32-bit mode. VCPI was provided by the Expanded Memory manager in DOS (e.g. CEMM , QEMM , later EMM386 ). It got eclipsed by DPMI, notably because it was not supported for DOS programs run in Windows 3.0's most powerful ''386 enhanced'' mode. It also did not work with OS/2 2.0 and later. Windows 3.0 only supported VCPI in Standard and Real modes. Earlier Windows/386 2.1 was not compatible with DOS extenders at all. VCPI also had a more limited scope, in that it basically only allowed a protected mode DOS program to run ''at all'' when such a program was started from DOS already running inside a Virtual 8086 Mode task, typically because a Memory Manager was installed and operating as a ''virtual {Link without Title} control program'' for the processor. Indeed, because the virtual 8086 mode fully isolates programs from the hardware, without some support from the control program, it is not possible for another program to switch to protected mode by itself. EXTERNAL LINKS ''This article was originally based on material from the Free On-line Dictionary Of Computing , used with . Update as needed.'' |
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