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The Psion Revo Plus

Update (2nd January 2010)

My Revo has long since fallen into disuse, after botched repair attempts by POS that left it broken. I simply make do without it now, wondering whether one day a spiritual successor will arrive. I do not live in hope.

As some of you already know, I am a proud owner of a Psion Revo Plus palmtop. I had wanted a such a gadget for many years when I finally got my hands on a Revo Plus back in February 2002. It is a clamshell case device, 155×79×17 mm, with a touch-sensitive 4.75″ 480×160 pixel greyscale LCD. It has an ARM 710T processor running at 36 MHz and features 8 MB of ROM and 16 MB of RAM. It runs Psion’s graphical EPOC operating system, revision 5 – development of which is now handled by Symbian, and the OS, now known as Symbian OS, is featured in mobile devices such as the Nokia Communicator. The Revo can also be made to run Linux. The main difference with the Revo Plus model over the original Revo is an extra 8 MB of RAM, and that the battery connector no longer comes loose and drops off. (US readers may have encountered the Psion Revo rebadged as a Diamond Mako.)

This little thing goes with me everywhere I do, and I am rather fond of it. Something that I particularly like, now that I have become more accustomed to Palm OS, is its ability to multitask pre-emptively. Unlike a Palm where you can’t run more than one app at once (although it gives the appearance that it can), I tend to leave apps running on the Revo for months and forget they are even open. Using Fn-System, I can switch back and forth between the two frontmost apps (even when they have dialog boxes open), which is also very convenient. EPOC compliments its ability to multitask with a robust kernel and protected memory, making for a very stable system and meaning that I never worry about the effects of any program on the system (and I have indeed had programs crash on me).

The open programs/files list

A more detailed and complete list of running processes can be seen with the ps command in Symbian’s eshell.exe. Included in the list are such built-in services as the window server, font bitmap server, and the SQL DBMS server.

I have quite a few uses for this device; in fact, I typed out an article on it earlier, using the in-built word processor, and then exported the file as plain text [I now have a proper text editor for it – Ed]. The selection of software provided with the system is decent, including a spreadsheet (with 2D/3D graphs), a flat-file database, a desk and scientific calculator and a nifty world-time clock. The Sketch program and the programming environment supplied with the Psion 5 were dropped for the Revo, maybe due to limited space in the 8 MB ROM, but both are available separately as free downloads, and I have both installed on this. Also supplied is a phone contacts editor, an e-mail client, and shipped with the device on a CD is copy of Opera for EPOC, although I do not have a use for these programs.

Word, with an article open for editing

Calc, a combined desktop/scientific calculator

The time application supplied with the machine is pretty nifty. As well as providing six alarm slots (with alarm modes such as weekly and workdays), it has a handy world time facility. It will offer the time at any one of its preset cities around the world, and you can add your own locations into it (the Astrodienst Atlas is good for getting latitude and longitude). It will tell you the distance between the local and remote location (available in miles, kilometers and nautical miles), and the current time, sunset and sunrise time, and area code of both locations.

Time in map mode, showing the time in Moncton, New Brunswick, and my home.

Admittedly one of the primary uses for me of the device is entertainment. One of the third-party programs of which I make the most use is Pyramid, a pyramid solitaire game, which I used to pass the time when sat at a bus stop, or when otherwise in need of something to do. Of course, the machine would not be complete without a copy of Tetris, and Atomic is the Tetris clone I run.

Pyramid solitaire


EPOC uses a file system that resembles that of DOS – it uses DOS-style paths, and paths are limited as with DOS to 255-chars. The RAM drive is assigned to C: and the secret ROM drive with the kernel and built-in software on is assigned to Z: (most software declines to provide access to this drive). The file system browser in EPOC, like virtually all EPOC programs, does not support drag-and-drop, so instead makes use of Windows-style cut, copy and paste to move and copy files around.

EPOC also supports OLE to level 1. When I installed Sketch, it appeared in the list of programs that can generate objects, thus allowing me to insert sketches into any OLE host programs such as Word and Jotter. The OS also has a clipboard for copying text, graphics and objects between applications. Another nice touch is that dialog boxes can be dragged around the screen (with live window draggging), in case they obscure part of the screen.

The System screen open on the RAM drive

Jotter, showing styled text and an inserted Sketch object

A rigged situation with two menus open at once; notice the shadows

I have quite a lot of extra software installed on the device, including several programs of my own. Psion’s choice of the most important apps are selectable via a row of silk-screened icons at the bottom of the display. The Extras button lets you see all the rest, including the built-in office software. It is not hierarchical; any icons that won’t fit are placed into a More menu.

The extras bar for launching software; the More menu is open

Two other third-party applications worth a mention are QuickNote, and Shell5. QuickNote is the application with which I drew all the sketches posted on this site. Shell5 is shell application that resembles bash but uses DOS paths from EPOC. Written in OPL, it has an API which you can use to write plugins for it to add new commands.

The QuickNote sketch pad program

The third-party Shell5 application, written in OPL

EPOC comes with an OPL runtime engine, for running software written in Psion’s Organiser Programming Language. With the free program editor installed, you can write and translate your own software (into bytecode I assume) for it on the machine itself. I eventually got into programming in OPL, and wrote a two-player program called Lecture Battleships for the machine. I also wrote a little random number generator app, for which I spent more time designing the icon than anything.

OPL, a variant of BASIC, is a pretty primitive language – it has no structs, no pointers, no multi-dimensional arrays, and strings are limited to 255 characters. It is not object-oriented. It does have heap memory allocation, however. For those wanting a more sophisticated development environment, you can develop software for it in C on a PC although this option is not available for Mac users like myself. Another alternative is Neuon’s nOPL+, which extends OPL with features like structs and pre-processor directives, translating the end result into regular OPL code that can be run as normal.

Like most other operating systems, this one comes replete with its own set of meaningless yet bemusing crash dialogs – the following one came up while I was attempting to uninstall an application. It could possibly be dependency-related (as that may have been the uninstall that took out a module that I didn’t want to lose), but I do not know.


Psion sold a MacConnect package 1 permitting a Psion to be connected to a Mac for file transfer (but sadly, no file translation) and back-ups. The software supports Mac OS up to 9.

A menu is added to the menu bar for controlling the connection to the Psion. When connected, the device is mounted as a disc on the desktop, and you can open and save files just as with a normal disc. Use of contextual menus during this period, though, may cause a crash – I am uncertain, so no longer try. Being able to copy files off the machine like this feels pretty funky :) Note that, although I have no translation in MacConnect, GraphicConverter natively supports EPOC multi-bitmap images (.mbm files) and Sketch images, and SoundApp supports EPOC sound files, and Word will export to plain text, so that generally does me fine. Neuon’s nConvert program can also be used to provide a suite of conversion tools directly on the machine.


Daniel Beardsmore, 9th September 2003 (corrected on Tuesday 24th November 2003, and modified on Saturday 6th November and Monday 15th March 2004; revised August 3rd 2004, June 1st 2007)
Comments? Send them to the author.


1 Several people have expressed interest in this topic – please see my MacConnect page for more information.