Command: jemmex
JEMMEX is an Expanded Memory Manager which has an XMM already included.
JEMMEX has to be loaded in CONFIG.SYS / FDCONFIG.SYS.
Syntax:
DEVICE=[drive][path][jemmex.exe] [options]
drive The drive letter, e.g. C:
path The directory, e.g. \example\
or run it from the command line:
[drive][path][jemmex.exe] [options]
Options:
+A20/NOA20 A20-disable emulation on/off (default on).
A20METHOD:m Set A20 switch method. Possible values for m are
KBC, PS2, BIOS, FAST, PORT92 and ALWAYSON.
ALTBOOT Use alternate reboot strategy.
B=segm Specify lowest segment address for EMS banking
(default=4000).
D=n Set DMA buffer size in KB (default=64, max is 128).
EMX Increased EMX DOS extender compatibility.
FASTBOOT Fast reboot. Requires JEMMEX to be loaded in CONFIG.SYS.
FRAME=E000 Set EMS page frame (FRAME=NONE disables frame). Any value
between 8000 and E000 is accepted, but not all will work.
HMAMIN=n Set minimum amount in KB to allocate the HMA.
I=start-end Force a region to be used for UMBs. Without this option
range C000-EFFF is scanned for unused pages. May also
be used to add (parts of) regions A000-BFFF or F000-F7FF
as UMBs. Don't use this option if you don't know what you
are doing!
I=TEST Scan ROMs for unused pages, include found regions as UMBs.
[MAX=]n Limit for VCPI (and EMS if < 32MB) memory in KB
(default 120 MB).
MAXEXT=n Limit extended memory usage to n KB.
MIN=n Reserve up to n KB for EMS/VCPI memory on init
(default=0).
MOVEXBDA Move XBDA into UMB. Some BIOSes won't allow this.
NOCHECK Disallow access to address space without RAM (MMIO).
NOE801 Don't use Int 15h, E801h to get amount of ext. memory.
NOEMS Disable EMS handling.
NODYN No dynamic XMS memory allocation (use MIN= to set fix
amount).
NOHI Don't move resident part into first UMB.
NOINVLPG Don't use INVLPG opcode.
+PGE/NOPGE Page Global Enable feature usage on/off (default off).
RAM/NORAM Try to supply UMBs on/off (default on).
S=start-end Assume Shadow-RAM activated by UMBPCI, include it as UMB.
SB SoundBlaster driver compatibility mode.
SPLIT Regain partially used EPROM 4k pages for UMBs.
+VCPI/NOVCPI VCPI Support on/off (default on).
VDS/NOVDS Virtual DMA Services on/off (default on).
+VME/NOVME V86-Mode Extensions on/off (default off).
VERBOSE Display additional details during start (abbr: /V).
X=start-end Exclude region from being touched or used by JEMMEX.
X=TEST Scan memory region C000-EFFF for UMB exclusion.
X2MAX=n Max. value in KB for XMS V2 free memory report
(default=65535).
XMSHANDLES=n Number of available XMS handles (8<=n<=128, default=48).
/? Shows the help.
'+': option can be set dynamically by running JEMMEX from the command
line.
When invoked from the command line JEMMEX additionally will understand:
LOAD install
UNLOAD uninstall
Comments:
JEMMEX requires a 80386+ CPU. Load JEMMEX as DEVICE=JEMMEX.EXE in
CONFIG.SYS (although it is an ".exe"-file!
JEMMEX has to be loaded in CONFIG.SYS / FDCONFIG.SYS.
JEMMEX most likely is the better choice than HIMEMX / JEMM386 because
it will need less DOS memory than an external XMM + JEMM386.
For more informations see:
https://github.com/Baron-von-Riedesel/Jemm/tree/master/Html
OR:
https://gitlab.com/FreeDOS/base/jemm/-/tree/master/DOC/JEMM
OR:
C:\FREEDOS\DOC\JEMM\readme.txt (can be installed with FD live CD).
Examples:
IN CONFIG.SYS / FDCONFIG.SYS:
files=20
buffers=30
lastdrive=Z
break=off
DOS=high,umb
device=C:\FREEDOS\BIN\jemmex.exe
shellhigh=C:\FREEDOS\BIN\command.com C:\FREEDOS\BIN /E:1024
/p:C:\fdauto.bat
See also:
config.sys/fdconfig.sys
devload
(fdxms)
(fdxms286)
himemx
jemm386
xmgr
Copyright © 2011 W. Spiegl updated 2022.
This file is derived from the FreeDOS Spec Command HOWTO.
See the file H2Cpying for copying conditions.