Note: This API calls are shared between DOS and Win16 personality.

DPMI is a shared interface for DOS applications to access Intel 80286+ CPUs services. DOS DMPI host provides core services for protected mode applications. Multitasking OS with DOS support also provides DMPI in most cases. Windows standard and extended mode kernel is a DPMI client app. Standard and extended mode kernel differs minimally and shares common codebase. Standard Windows kernel works under DOSX extender. DOSX is a specialized version of 16-bit DPMI Extender (but it is standard DPMI host). Standard mode is just DPMI client, exnhanced mode is DPMI client running under Virtual Machime Manager (really, multitasker which allow to run many DOS sessions). Both modes shares DPMI interface for kernel communication. The OS/2 virtual DOS Protected Mode Interface (VDPMI) device driver provides Version 0.9 DPMI support for virtual DOS machines. Win16 (up to Windows ME) provides Version 0.9 DPMI support.

DPMI host often merged with DPMI extender. Usually DPMI extender provide DPMI host standard services and DOS translation or True DPMI services.

2021/08/05 12:15 · prokushev

Int 31H, AH=07H, AL=02H




Mark Page as Demand Paging Candidate


AX = 0702H
BX:CX = starting linear address of pages to mark as paging candidates
SI:DI = size of region to mark (bytes)


if function successful
Carry flag = clear

if function unsuccessful
Carry flag = set
AX = error code
8025H	invalid linear address (range unallocated)


Notifies the DPMI host that a range of pages may be placed at the head of the page-out candidate list, forcing these pages to be replaced ahead of other pages even if the memory has been accessed recently. The contents of the pages will be preserved.

This function does not force the pages to be swapped to disk immediately and should be treated as advisory only.

This function will always succeed on hosts that do not implement demand-paged virtual memory.

Partial pages will not be marked.

This function is useful, for example, if a client knows that a given piece of data will not be accessed for a long period of time. That data is ideal for swapping to disk so that the physical memory it occupies can be used for other purposes.

See also


Process manager INT 2FH 1680H, 1687H
Memory manager
Misc INT 2FH 1686H, 168AH
2021/08/13 16:23 · prokushev

en/docs/dpmi/api/int31/07/02.txt · Last modified: 2021/08/27 08:10 by prokushev