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.