Command: jemm386
JEMM386 is an Expanded Memory Manager.
JEMM386 has to be loaded in CONFIG.SYS / FDCONFIG.SYS.
Syntax:
DEVICE=[drive][path][jemm386.exe] [options]
drive The drive letter, e.g. C:
path The directory, e.g. \example\
or run it from the command line:
[drive][path][jemm386.exe] [options]
Options:
+A20/NOA20 A20-disable emulation on/off (default on).
ALTBOOT Use alternate reboot strategy.
B=#### Specify lowest segment address for EMS banking
(default=4000).
D=### Set DMA buffer size in kB (default=64, max is 128).
EMX Increased EMX DOS extender compatibility.
FASTBOOT Fast reboot. Requires Jemm386 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.
I=D000-D7FF 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=]##### Limit for VCPI (and EMS if < 32M) memory in kB
(default 120 MB).
MIN=##### Reserve up to ##### kB for EMS/VCPI memory on init
(default=0).
NOCHECK Disallow access to address space without RAM (MMIO)
NOEMS Disable EMS handling. Use NOEMS to get more
free UMBs if you need no EMS.
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=D000-D7FF 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 on).
VERBOSE Display additional details during start (abbr: /V).
X=D000-D7FF Exclude region from being touched or used by Jemm386.
X=D000-D7FF can be needed e.g. for some network.
X=TEST Scan memory region C000-EFFF for UMB exclusion.
/? Shows the help.
'+': option can be set dynamically by running Jemm386 from the command
line.
When invoked from the command line Jemm386 additionally will understand:
LOAD install
UNLOAD uninstall
Comments:
JEMM386 requires a 80386+ CPU. HIMEMX should be loaded before.
Load JEMM386 as DEVICE=JEMM386.EXE in CONFIG.SYS (although it is
an ".exe"-file!
JEMM386 has to be loaded in CONFIG.SYS / FDCONFIG.SYS.
Examples:
IN CONFIG.SYS / FDCONFIG.SYS:
device=c:\fdos\bin\himemx.exe
device=c:\fdos\bin\jemm386.exe
See also:
config.sys
devload
(emm386)
fdconfig.sys
(fdxms)
(fdxms286)
(himem)
himemx
jemmex
xmgr
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Copyright (C) 2011 W. Spiegl.
This file is derived from the FreeDOS Spec Command HOWTO.
See the file H2Cpying for copying conditions.