The IBM PS/1 emulator.
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.



IBMulator is a free/libre, open source emulator for the IBM PS/1, able to run with the original ROM. The goal is to create a faithful simulator capable of recreate the look and feel of the real machine.

IBMulator v0.9 can emulate the following systems:

  • IBM PS/1 model 2011 (286 10MHz)
  • IBM PS/1 model 2121 (386sx 16MHz,20MHz)

In order to use the program you'll need the original ROM, which is copyrighted by IBM. You won't find it distributed with this package.

See the project page at for screenshots, videos and additional information.


IBMulator is distributed under the GNU GPL version 3 or (at your option) any later version. See COPYING for details.

To obtain the source code go to


A 64-bit Linux or Windows operating system, a OpenGL 3.3 graphics card, and a 2GHz dual core processor.


First of all obtain the original ROM. You have the following options:

  1. if you have a real PS/1, take the program ROMDUMP.EXE in the 'extra' folder and put it in an empty floppy disk; insert the floppy disk in your PS/1 and launch the executable: it will create the ROM image on the floppy disk
  2. or open your PS/1, extract the EPROMs and read them with an EPROM reader (you also need to merge the 2 halves in 1 file, or 4 in 2 if you have a non-US model)
  3. or scour the Internet (there are various ROM sets available.)

Launch IBMulator. A window will inform you that the file ibmulator.ini has been created and where it is placed.

Put the ROM set anywhere you like (inside the same directory of ibmulator.ini is a good place) and update ibmulator.ini with the file name of the ROM you want to use (see below for the correct format.)

From now on IBMulator is ready to run.

For more information regarding the configuration options, see the comments inside ibmulator.ini.

Being a faithful emulator of the PS/1, to configure the system (ie. the PS/1, not the emulator) after a configuration change (for instance, if you add or remove a floppy drive), you need a DOS program called CONFIGUR.EXE, otherwise you'll get various POST errors. Likewise, if you want to customize the way the system works, you need to use the program CUSTOMIZ.EXE. Both files are copyright IBM and you have to search the Internet in order to obtain them.


You may want to select the correct keyboard mapping under the [gui] section.

Currently valid keyboard mappings are:

  • keymaps/ (US keyboard)
  • keymaps/ (Italian keyboard)

If you want to create a new mapping for your language, use one of the available files in the share/ibmulator/keymaps directory as a template.

If you'll create one please consider sending me a copy :-)

ROM set

A ROM set can be:

  1. a compressed archive in the ZIP format
  2. a file with the *.BIN extension, named as you like
  3. a directory

A ZIP archive or directory must contain (case insensitive):

  • FC0000.BIN : the system BIOS ROM, 256KiB
  • F80000.BIN : the regional ROM, 256KiB, optional, only for non-US versions. For international models, this bin file can be merged with FC0000.BIN to form a single 512KiB bin file. In this case FC0000.BIN, if present, is ignored.

Any other file present in the archive or directory is ignored.

HDD image

The first time you launch IBMulator an empty pre-formatted hard disk image will be created.

If you have an original PS/1 backup disk-set you can restore the machine to its factory state. In order to do so:

  1. insert a PC-DOS 4.0 floppy disk in drive A
  2. go to the DOS prompt
  3. run "a:restore a: c: /s"

Under Linux you can mount the HDD image using this command:

$ mount -o loop,offset=16896 hdd.img /mnt/loop

The offset value is equal to "start sector"*512. The start sector value can be determined with:

$ fdisk -l hdd.img

Note: if you use the custom HDD type 47, the automatically created image will be 0-filled and you'll need to use 'fdisk' and 'format' in order to use it.

GUI modes

IBMulator has 3 different GUI modes.

  • Compact: in this mode the VGA image fills the available window space and the control panel, in the shape of the PS/1 system unit, disappears when input is grabbed or CTRL-F1 is pressed. Use this mode if you want an experience similar to DOSBox.
  • Normal: this is the default mode. The control panel / system unit places itself at the bottom of the VGA display and is always visible.
  • Realistic: this is the hardcore mode, for the retro enthusiasts who want to truly experience the PS/1. In this mode the system is rendered in its entirety, monitor included. There are no additional buttons and controls except the originals: volume, brightness, contrast, power, and floppy (you need to use the key bindings for any extra function.) The PS/1 type 2011 is 32 cm (12.6") wide and 34.9 cm (13.74") tall, so you need at least a 24" 16:10 monitor in portrait mode (rotated) to render it at real size.

You can select the GUI mode under the [gui] section of the ini file.

Key bindings

  • CTRL+F1: show/hide the main interface (only if GUI is in compact mode)
  • CTRL+F3: toggle the machine power button
  • CTRL+F4: show/hide the debug windows
  • CTRL+F5: take a screenshot
  • CTRL+F6: start/stop audio capture
  • CTRL+F7: save current state
  • CTRL+F8: load last state
  • CTRL+F10: mouse grab (only if CTRL+F10 is the mouse grab method)
  • CTRL+F11: CPU emulation speed down
  • CTRL+F12: CPU emulation speed up
  • CTRL+DEL: send CTRL+ALT+DEL to the guest OS
  • CTRL+INS: send SysReq to the guest OS
  • ALT+ENTER: toggle fullscreen mode
  • ALT+PAUSE: pause/resume emulation
  • ALT+F4: exit the program

If the grab method is 'MOUSE3', use the central mouse button to lock the mouse.

Command line options

-c PATH Sets a configuration file to use
-u PATH Sets a user directory from where the program reads the ini file and stores new files, like screenshots and savestates
-v NUM Sets the logging verbosity level (from 0 to 2)


For Windows instructions see

For Linux instructions see


I would like to thank the Bochs team. I've taken a huge amount of code from the project. Thank you guys, you made a terrific job! Without your work IBMulator would have taken at least a decade to reach the point where it is now.
Also thanks to the DOSBox team. Some code from them as well and a lot of information and inspiration.