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One of the great things about the Psion computers is how easily they can be programmed.

This can be done on the Psion machine itself (using the built-in OPL editor) or by using a PC-based software development kit (SDK), software development environment (SDE) or Psion 'emulator'.


This page offers no more than a point in the right direction in obtaining the right tools for the job. My own interest and experience is in OPL16 on SIBO machines.

I am no programming expert, just a keen amateur, but I hope to be able to point you in the right direction towards the information you need.


MS-DOS iconEmulators

Check out the SIBO Emulators page for details about the Psion Series 3, Series 3a, Siena and WorkAbout emulators. These run the SIBO O/S under an MS-DOS environment (not a Windows Shell to DOS) and allow you to test, run or develop SIBO software.

There is a neat trick that increases the screen size of the emulator to 480 x 640 pixels, which allows you to see more lines of code in the OPL Editor.

Go to the SIBO Emulators page.


psicon-opl.gif - 1kbOPL 16

What is OPL?

OPL is a BASIC-like language which is fairly simple to learn. It is a structured, not object-oriented, language. OPL stands for Organiser Programming Language.

The term 'OPL16' is used to denote the version of OPL for the SIBO (16-bit) Psion machines. The term 'OPL32' is used to denote the EPOC/Symbian 32-bit version of the OPL programming language. Much of the OPL language is the same for both OPL16 and OPL32. Leigh Edwards describes the differences in his book "Programming Psion Computers".

Types of OPL

Psion produces two type of machines:

  1. The Organiser II. Several models are available including the XP, CM, LZ and LZ64

  2. SIBO machines. SIBO is a generic name for Psion
    machines that run the Psion EPOC operating system.
    The following machines are all SIBO machines: MC200,
    MC400, HC100, HC110, HC120 and the Series 3, 3a, 3c, 3mx, WorkAbout and Siena.

There are currently at least 5 variants of the OPL language:

  1. XP-OPL running on Organiser IIs (Model XP and

  2. LZ-OPL running on Organiser IIs (Model LZ and
    compatibles). Contains some enhancements to XP-OPL.

  3. MC-OPL running on older SIBO machines (MC200 and
    MC400). Contains many enhancements over LZ-OPL

  4. OPL/g running on recent SIBO machines (MC200, MC400,
    HC100, HC110, HC120). OPL/g includes all MC-OPL
    enhancements plus commands to draw graphics.

  5. OPL/w running currently only on the Series 3. OPL/w
    includes all OPL/g enhancements plus new WIMP

  6. I assume that the Series 3a, WorkAbout, Series 3c, Siena, WorkAbout mx and Series 3mx brought along new versions of OPL, but I am now sure which version this is.

One advantage of programming in OPL is that you can take your programming with you, on your Psion machine; you are not tied to developing on a PC. Adrian Collister, for example, programmed his Mah Jong for EPOC application entirely on a Psion handheld.


How do I learn OPL?

The OPL manual, downloadable below, is an excellent starting place to learn OPL. I thoroughly recommend that you download the PDF version and print it, if you are able, and keep it on hand as a book resource.

Programming Psion Computers

Another excellent resource for the OPL programmer is Leigh Edwards' book "Programming Psion Computers".

This is now available as a free download (2.8 MB, PDF) from EMCC's website .


OPL Manual downloads

The OPL Manual is available for free download in a number of formats (all downloads are zipped):

download psion dbf format - 253 Kb SIBO Data .DBF (253 KB) download psion dbf format - 253 KB
EPOC R5 Help application (196 KB) download EPOC R5 Help application - 196 KB
download windows help format - 198 Kb Windows Help (198 KB) download windows help format - 198 KB
MS Word .DOC (665 KB) download MS Word .DOC format - 665 KB
ASCII Text (182 KB) download ASCII text format - 182 KB
download html format - 117 Kb HTML (117 KB) download html format - 117 KB
download pdf format - 1820 Kb PDF !! RECOMMENDED !! (1,820 KB) download pdf format - 1820 KB


OPL Manual by chapter

The OPL Manual from Psion is also available in PDF format arranged by chapter. This version is dated 1997 and covers programming the Siena, Series 3 and Series 5 machines, though no doubt much will also apply to the Workabout, Revo, Series 7 and NetPad.

View: You will require Adobe Acrobat (Reader) 4.0+, or the newer Adobe Reader (which is free) installed in order to view these files in your browser, and indeed on your computer!

Download: The whole manual can be downloaded as one zipped file (see above).

Clicking each link, below, will open the file in your browser if you have an Acrobat plug-in.

To simply download each chapter, right-click a link below and select "Save Target As..." to download them without opening them in your browser.

download ch 1: introduction (47 KB)
download ch 2: basics (216 KB)
download ch 3: database (114 KB)
download ch 4: gui (278 KB)
download ch 5: disks (38 KB)
download ch 6: programs (77 KB)
download ch 7: errors (84 KB)
download ch 8: advanced (351 KB)
download ch 9: glossary (493 KB)
download appendices (203 KB)
download series 5 opx (255 KB)

OPL Manual on-line

The OPL Manual is no longer available on-line (in HTML format)


OPL16 Tutorials

There are a number of great resources online, as well as the OPL Manuals (above) and Edward Leigh's "Programming Psion Computers" book, which will give you an in-depth look at programming in OPL16.

  • Steve Litchfield on his 3-Lib site has a very good beginners guide to writing programs in OPL (both OPL16 and OPL32).

    Check out his OPL tutorials here.

    He also includes a good section on tips for the distribution of software.

  • Jochen's OPL Programmers Workshop.

  • Andrew Lord has a good OPL Programming section.

  • RMR Software have made RMREvent for SIBO available for free download. RMREvent is a fully-working demonstration for an event-driven application. It provides all the tools you need, inside a demonstration framework program, to start programmimg in OPL.


Advanced Programming


Development Kits and Environments


This comprises two A4 folders, the Psion OPL software environment, and ODE (a Windows-based OPL Development Environment).

This Software Development Kit costs £120 and possibly may still be available from John Hill Computer Services Ltd. on 01226 206575, or e-mail jhcs.ltd@virgin.net.


The OPL Development Environment (a Windows-based OPL application) can also be obtained separately.

This requires Windows 3.1x or above and is designed to be used with a Series 3, Series 3a, Workabout or HC - it can be used with a Siena or Series 3c/mx although the baud rate on the machine will have to be reduced from its default maximum.

This SDE can be bought from Psion Ex for around £5.00 plus £1.00 postage and packing, or is available on my SDK CD-ROM #1.


The SIBO Emulators are useful tools for writing OPL applications. They only run under MS-DOS (not a Windows Shell to DOS) and with a cunning tweak the display can be increased to 480 x 640 pixels. The PC keyboard is obviously easier to type on than the smaller Psion one.


OPL Code Studio (497KB Zip) is aWindows-based text editor that allows you to also compile code to APP or OPO format.


Another Windows-based editor is OPLEditor 2 from Mitdata.com. This is now freeware, and unsupported, although it has a very unfinished feel to it.

OPLEditor is a programming editor for the OPL16 / 32 language, that allows you to edit, transfer and translate an OPL program in a standard PC and transfer it directly to a SIBO (Siena, Series 3) or EPOC (Revo, Series 5) device.


S3aTran is a command-line MS-DOS application from Psion that allows you to specify a source file and have S3aTran translate it into a SIBO application.
Download S3aTran (57 KB, Zip)

Contact us

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GJ5 forum

Quick Links

Psion.com -- Home Page

My Psion -- Official Support and Downloads

Symbian Developer Network -- Support and SDK Downloads