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
Please read this command's lsm file also.
You will find the updated version (internet) here and
the version described in this manual page here.
The lsm file contains information about the name of the programmer,
the download site, and some other command related information.
Copyright © 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.