VXMS Device Driver
The Extended Memory Specification (XMS) Version 2.0 provides a standard
interface for the use of three regions of extended memory on 80286 and 80386
machines:
High Memory Area (HMA), accessible in real mode if
the A20 address line is enabled
Extended Memory Blocks(EMBs), up to 64MB that is used
for data storage
Upper Memory Blocks(UMBs), located between 640KB and
1MB in conventional memory.
The Virtual Extended Memory Specification(VXMS) device driver
Implements all the functions of XMS Version 2.0
Provides each virtual DOS machine with its own separate
XMS emulation
Provides configurable limits on the amount of extended
memory for each virtual DOS machine separately.
The VXMS device driver is installed via CONFIG.SYS, with the following syntax
and options:
Syntax
DEVICE=\OS2\MDOS\VXMS.SYS [options]
Options
XMMLIMIT=g,i
Set the global maximum
memory usage of VXMS to gKB, and the per virtual DOS machine limit
to iKB. The default is 16384,2048.
/HMAMIN=d
Minimum request size in KB for an HMA request
to succeed. The default is 0, the maximum is 63.
NUMHANDLES=n
Number of handles available to each virtual
DOS machine. Handles are used to access EMBs. The maximum is 128 and
the default is 32.
/UMB
Create
UMBs. The default is not to create any.
/NOUMB
Do not create UMBs. This is the default setting.
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