XMGR.SYS is a DOS driver that works as an XMS memory manager.
XMGR.SYS has to be loaded in CONFIG.SYS / FDCONFIG.SYS.
DEVICE [HIGH] = [path] XMGR.SYS [/B] [/Mn] [/Nnn] [/PA] [/Tn] [/W] [/Z]
XMGR.SYS usually needs only its /B switch if "booting" with
JEMM386. XMGR.SYS switch options are as follows:
/B Specifies "boot" mode. XMGR.SYS loads in temporary memory
until upper-memory is enabled by EMM386. Without /B,
XMGR.SYS will load stand-alone in low memory or directly
in upper-memory with UMBPCI.
/Mn Specifies the temporary area used to load XMGR.SYS in
"boot" mode and used for UMBPCI upper memory I/O before
DOS can post a "workspace" buffer. Values are:
/M1 = 64K. /M3 = 192K. /M5 = 320K. /M7 = 448K.
/M2 = 128K. /M4 = 256K. /M6 = 384K. /M8 = 512K.
Without /M, /M5 is assumed and the 320K area will be used.
NOTE: A DOS system often may NOT load at address 0 up and
may leave temporary data anywhere in memory! /Mn changes
the temporary area to find a "safe" place for XMGR.SYS
to use. /M is ignored if XMGR.SYS loads stand-alone.
/Nnn Specifies how many XMS "Handles" can be used by DOS programs.
The value nn may be 48, 80, or 128. If /N is omitted, 48
"Handles" are used and work fine for most systems. A big
system doing much XMS work may need 80 or 128 "Handles".
/PA Specifies use or non-use of PS/2 Port 92h logic to handle the
/PN system's "A20" line. /PA indicates "Always" use Port 92h
logic. /PN indicates "Never" use it and handle "A20" via
normal keyboard-port logic. If /P is omitted, XMGR "asks
the BIOS" if the system has Port 92h logic. If not, XMGR
will use normal "A20" logic. NOTE: If "A20" was enabled
by DOS before XMGR loads, XMGR does not handle it at all!
/Tn Specifies the BIOS requests to use in getting extended memory
/T0 Neither "E820h" nor "E801h" requests.
/T1 Memory-list requests only (Int 15h, AX=E820h).
/T2 A dual-area request only (Int 15h, AX=E801h).
/T3 "E820h" requests first, then an "E801h" request.
/T can usually be omitted, which causes /T3 to be assumed.
In addition, XMGR.SYS always uses an old 64-MB request, to get
extended memory for /T0, or if the requests specified with
/T1 through /T3 are unsuccessful. Users may need to test
/T1 and /T2 separately, to see if their BIOS accepts them.
A pre-1994 BIOS may not "ignore" /T1 through /T3 properly and
may require /T0 to be used. For compatibility with older
QHIMEM drivers, /T4 through /T7 may be used and work the same
as /T0 through /T3.
/W Specifies use of the DOS "workspace" buffer, for upper-memory
I/O if loading with UMBPCI. If /W is omitted, or if the
DOS system does not have proper workspace logic, XMGR.SYS
will set its own buffer in low memory. An EDR-DOS system must
OMIT this switch! Without UMBPCI, /W will be ignored.
/Z For XMGR or UIDE only, limits their XMS moves to a maximum 2K
bytes in protected-mode, not 64K. /Z is ignored by real-mode
systems (UMBPCI etc.) and is not needed if JEMM386 or EMM386
handle protected-mode. Systems using other VCPI/DPMI/EMM
drivers must be TESTED, to see if /Z is needed by XMGR or UIDE
-- BAD schemes allowing NOT enough interrupts in an XMS move
may still exist! UIDE's old /N4 switch is the same as /Z and
can still be given. UIDEJR ignores /Z or /N4 and always
issues standard XMS calls.
For each switch, a dash may replace the slash, and lower-case letters
may be used.
XMGR.SYS is a DOS driver that works as an XMS memory manager. It
supports V3.70+ UMBPCI by Uwe Sieber. After UMBPCI enables upper-
memory, XMGR.SYS can load there directly and provide both upper and
XMS memory for a DOS system. XMGR.SYS uses an "I/O catcher" with
UMBPCI, to intercept diskette or hard disk I/O above 640K. Such I/O
is done through a low memory area, to avoid DMA trouble in UMBPCI
"Shadow RAM". XMGR.SYS also supports V4.49 and V4.95 EMM386 (MS-DOS
V6.22 or V7.10). With JEMM386, XMGR.SYS using its /B switch can first
"boot" into temporary space. After JEMM386 enables upper-memory,
XMGR.SYS loads there with no /B switch, copies all its "boot" data,
and takes-over XMS work. Only its XMS "Handles" table stays in low
memory, so EMM386 can always find them at fixed addresses. For a
small XMS-only system, XMGR.SYS can also load entirely in low memory.
For more information read "README.txt" in drivers.zip.
In CONFIG.SYS / FDCONFIG.SYS:
SHELL=C:\DOS\COMMAND.COM C:\DOS /E:512 /P
DEVICE=C:\BIN\JEMM386.EXE I=B000-B7FF X=C800-EFFF NOEMS ;Optional
DEVICEHIGH=C:\BIN\UIDE.SYS /S500 /D:CDROM1 ;Or UIDEJR
DEVICEHIGH=C:\BIN\RDISK.COM /S250 ;Optional
Copyright (C) 2007 Jack Ellis, updated 2011 by W. Spiegl.
This file is derived from the FreeDOS Spec Command HOWTO.
See the file H2Cpying for copying conditions.