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Psion SIBO Emulator under DOSBox

Written by guest writer Les Hollingbery


The Psion SIBO emulators, for example the Series 3a emulator, were designed to run on a dedicated PC under DOS. They do not run in a DOS command window. This paper describes a technique using DOSBox, a freely available DOS emulator, which can host the SIBO emulator so that the remaining facilities of XP or Windows 2000 are simultaneously available. In other words it no longer needs a dedicated PC. This means that when developing software for the SIBO emulator, you can access its internal drives using windows explorer rather than having to use a remote link.

So you have a window running DOSBox and within that window the SIBO emulator. The DOSBox has certain commands which, for example, pause it or shut it down. This implies two things; 1, that the SIBO emulator will be paused or shut down as well and 2, that those keys are not available to the SIBO emulator. This paper discusses ways of coping with this.

You use this technique at your own risk. Although testing has been done and nothing untoward has happened, neither I nor Steve Litchfield or DOSBox or Psion can be held responsible for anything that may or may not happen as a result of using this technique.

Booting up


It is recommended that you are up to date with the backups of your PC, and that you close any applications that are running until you are left with a desktop.

Download DOSBox

DOSBox can be downloaded from http://dosbox.sourceforge.net and click on downloads.

There is a choice of platforms; I chose Windows version 0.63 win32 installer.

You then get a choice of mirror sites; I chose Kent, UK.

This puts DOSBox0.63-win-32-installer.exe (1MB) on your PC. This does not install DOSBox until you click on it. This is described in the Installation section.

Download the SIBO Emulator

This can be obtained from 3lib on the cd or from http://home.hccnet.nl/joop.nijenhuis/emule.htm

Put it into a folder so you know where the original code is. Please read the licence.txt that comes with it.


This section assumes you have read and carried out the instructions in the Downloads section.

Installation of DOSBox

Click on DOSBox0.63-win-32-installer.exe

When clicked this installs C:\Program Files\DOSBox-0.63 and within this are the files dosbox.exe (the DOS emulator) and dosbox.conf and COPYING.txt Please read COPYING.txt it explains the terms of the license and the readme.txt has a section on keymapper which is worth reading.

Further instructions are in the 'Customisation of DOSBox' section of this paper.

Installation of SIBO Emulator

As a suggestion I will name various folders/directories and if you follow this, you will find that it matches up with the customisation of DOSBox. It will also enable you to try other varieties of SIBO emulator without too much additional work. (Note that if you change the variety of SIBO emulator you will need separate "internal drives" because the format of the files they create are specific to the model).

Use Windows Explorer (Not Internet Explorer) to create a folder C:\PSIEMUL and within this create a folder called S3A

Within C:\PSIEMUL\S3A create 3 separate folders called M, A and B So you now have C:\PSIEMUL\S3A\M C:\PSIEMUL\S3A\A C:\PSIEMUL\S3A\B (These are the internal drives of the SIBO emulator)

In the C:\PSIEMUL\S3A\M folder create separate folders called AGN, APP, DAT, IMG, OPD, OPL, OPO, SPR, WDR, WLD, WRD, WVE (If you know of any folders that will be used by your own application such as ASM, it is best to create them now.) If you are using the S3C emulator you will probably need JOT as well.

Copy all the files that you downloaded for the SIBO emulator into the folder C:\PSIEMUL\S3A


I found it easiest to keep the originals of files that I was modifying somewhere safe and to make the changes to copies. To make a change, I usually had to right click on the file and "open with" wordpad. When it came time to save, windows usually called it something like filename.config.txt so I then renamed it to filename.config which made it work with the application.

Customisation of DOSBox

There are two areas which need tailoring or customising. The first is the dosbox.conf file so that it assigns the internal drives on the emulator and then starts the emulator as part of the boot up of the DOSBox. The second is to customise the keyboard, using mapper.txt

The files should go into C:\Program Files\DOSBox-0.63

To install the samples first rename dosbox.conf to olddosbox.conf and then put the downloaded dosbox.conf into the same folder. And second, put the downloaded mapper.txt into the same folder. (If you want to go with the "original" mapping, then rename this file to oldmapper.txt before starting DOSBox, then DOSBox will not find a mapper and use a default setting.)

If you wish to use the sample files, then ignore the rest of this section which explains how to do it yourself

To customise the dosbox.conf first rename it to 'old dosbox.conf' and make a copy called 'dosbox.conf' Then edit 'dosbox.conf' with wordpad and look at the end of the file for:


# of lines in this section will be run at startup.

and after this type the following commands. (note this replaces the SUBST commands you may already be familiar with)

mount C C:\PSIEMUL
mount A C:\PSIEMUL\S3A\A
mount B C:\PSIEMUL\S3A\B
mount M C:\PSIEMUL\S3A\M
cd S3A

Save the file and if necessary rename it to 'dosbox.conf' instead of 'dosbox.conf.txt'

Customisation is required in order to reassign some of the keypresses which control the DOSBox which are also required to control the SIBO emulator. Other customisation just makes it easier to work with the keyboard (for example the numbers on the keypad have to be assigned to the same "event" as pressing the numbers across the top of the keyboard). Customising the keyboard is carried out once the DOSBox is working, so if you have not used the supplied mapper.txt wait until the DOSBox has been started (it does not matter if the SIBO emulator is running or not). Then press ctrl and F1 together (ctrl-F1 means the same) You select the key or event you want to map from the picture with the mouse, then you click on the add square on the picture, then you press the keys you want to use instead (If you want CTRL and/or ALT you have to do it using the picture; CTRL click on the picture mod1, ALT is mod 2; and then press the other key eg F9) You then have to delete the original keys for the event, otherwise you will get two ways of creating the same effect. Use the picture to click next and the choices will cycle round, you click on the picture del to remove one. Click on save to save the mapper.txt file.

Customisation of SIBO Emulator

I found that customisation was not required.


Start the DOSBox by clicking on dosbox.exe in C:\Program Files\DOSBox-0.63 (or a shortcut) and provided you have customised the file dosbox.conf the SIBO emulator will start up automatically (be patient the DOSBox has to boot up and then the SIBO emulator will go through its own boot up routines). The DOSBox has a "buddy" window which contains logging information. (The window with the emulator in it has a longer name and a windows flag on the icon in the tool bar.)

See the section on Control Keys for how to pause or shutdown the DOSBox, this will affect the SIBO emulator.

You can use windows explorer to move or rename or copy files on the "internal drives (M/A/B)" of the SIBO emulator. When you have done this you should press CTRL-F4 which will make the DOSBox aware of the changes, and then press F1 to make the SIBO emulator aware of the changes.

Time, a Psion S3a app


DOSBox http://dosbox.sourceforge.net

SIBO Emulators http://home.hccnet.nl/joop.nijenhuis/emule.htm


It's not a perfect world so you should expect that some things will not be as good as you hoped. Nevertheless there still should be enough left that you can get something out of the experience.

Remember that we have an environment consisting of wheels within wheels so trouble shooting is interesting; the DOSBox may or may not emulate DOS, the SIBO emulator may or may not behave the same as an actual Psion.

The following are some of the discrepancies that have been noticed. They are split into those which are probably due to one of the two emulations and a third category which I've called Environment to describe the two interacting.

Limitations of the DOSBox

It can be a bit slow to respond to the mouse/keyboard when it is in a loop.

It can soak up CPU cycles apparently not doing very much. You may want to PAUSE it when you don't really need it working (this will stop the clock on the SIBO emulator).

Limitations of the SIBO Emulator

Each time the emulator is started it is necessary to reinstall (Psion key-I) any applications that you previously installed. Files on the internal disk (M/A/B) will be available as they are not affected by restarts.

Limited emulation of the WVE sound system

Differences at the low-level filing system level.

Address trapping is implemented differently.

Caps lock works but does not show the symbol like a real Psion.

Shift diamond key does not work.

Limitations of the Environment

The SIBO emulator cannot create folders/directories. If it is trying to do this you will see a message on the DOSBox logging screen which says
Warning: file creation failed c:\PSIEMUL\S3A\M\WLD
and a blur of rapidly changing file names. If you click on the SIBO emulator window and press the Pause key (it should work both with and without shift key) this may pause the DOSBox. Open a window into the M folder using windows explorer and create a folder called WLD or whatever it says is a problem. Click on the SIBO Emulator window and press CTRL-F4 and then F1. This will instruct the DOSBox to notice the new folder and then instruct the SIBO emulator to notice it too. Sometimes you do not get any indication of which folder is missing, in these cases look at the documentation for the application you are working with and see if you can decide it from there.

F12 for diamond key does not work.

The clock runs slowly.

Control Keys

Control Keys DOSBox

If the sample mapper.txt file has been used then the following keypress will shut down DOSBox:
CTRL-ALT-F9 (ctrl and alt and F9 pressed simultaneously and held)

If the sample mapper.txt has not been used then the following keypress will shut down DOSBox:
CTRL-F9 (ctrl and F9 pressed simultaneously and held).

The following keypresses will affect the DOSBox and as such are unavailable to the SIBO emulator. If this causes you a problem, then use of the keymapper, explained in the readme.txt in the DOSBox folder may alleviate the problem.

Keyboard Key



Pause the DOSBox (and the SIBO emulator)


Go full screen and back (toggle)


Start the keymapper (which allows you to change the meaning of keys)


Swap mounted disk-image. Update directory cache for all drives! (needed when you move data in the SIBO emulator's internal drives by using windows. Use F1 to alert the SIBO emulator)


Save a screenshot.(png). Saved/Recorded files can be found in current_directory/capture (can be changed in the configfile). The directory has to exist prior to starting DOSBox else nothing gets saved/Recorded!


Start/Stop recording sound output to a wave file. See warning in CTRL-F5


Start/Stop recording of OPL commands. (Note this appears to be unrelated to SIBO OPL)


Start/Stop the recording of raw MIDI commands.


Decrease frameskip.


Increase frameskip.


Kill DOSBox. (Note this may be changed with keymapper sample file to CTRL-ALT-F9)


Capture/Release the mouse.


Slow down emulation (Decrease DOSBox Cycles).


Speed up emulation (Increase DOSBox Cycles).

These are the default keybindings. They can be changed in the keymapper.

Saved/recorded files can be found in current_directory/capture
(can be changed in the configfile). The directory has to exist prior to starting DOSBox else nothing gets saved/recorded !

Control Keys SIBO Emulator

Psion Name

Keyboard key

(Buttonbar) System


(Buttonbar) Data


(Buttonbar) Word


(Buttonbar) Agenda


(Buttonbar) Time


(Buttonbar) World


(Buttonbar) Calc


(Buttonbar) Sheet










Psion Key





Not implemented (should be F12). Use menu option instead.



Switch off

CTRL-ALT-Esc (Note this will display "Fatal application error 00" this is not a problem.)

Hope you enjoy it.


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