Category : HD Utilities
Archive   : VEMM.ZIP
Filename : READ.ME

VEMM/READ.ME Virtual Expanded Memory Manager

Please read the article by Charles Petzold on page 185 of
PC Magazine, Volume 6, Number 6 (March 31, 1987) titled "Emulating
Expanded Memory: Five Software Alternatives" for a good explanation
of the purpose of VEMM. Note that one of the products reviewed is
named V-EMM, but it is not related to the software accompanying
this documentation.


DISCLAIMER:

See the heading: "NOT 100 PERCENT COMPATIBLE" (page 187 of above
mentioned article). Charles Petzold put it well when discussing the
ability of expanded memory management emulation software to perfectly
emulate a true expanded memory (hardware) system: "They simply cannot".

This VEMM should work properly under the following conditions:

(1) Only the "general purpose programming" EMS calls
(functions 1 through 7) are used by an application.

(2) The application must not map the same virtual page to
more than one physical page simultaneously (this item is
discussed in the article, see pages 177, 178).

(3) Resident software cannot access the virtual expanded memory
outside of an EMM application. This is because VEMM uses a
DOS file handle to access the paging file, and DOS closes
file handles when applications terminate.

NOTE: Also because of (3), this VEMM is probably slower than any of
those mentioned in the review--some of which use BIOS for ac-
cessing the paging file rather than the slower services of DOS.