3. Introduction

The OpenPsion project is an effort to port the widely used Linux operating system to the various Psion hand held computers, and the Series 5mx/5mxPRO pocket computers, in particular. Some familiarity with linux in general is probably essential for getting OpenPsion going, although at least one of the prepackaged distributions (e.g., "Distorted Woody") are fairly complete and ready to go.

3.1. Why Linux on the 5mx?

It is sometimes asked why one would want to install and run linux on one's 5mx? Everyone has different reasons, but I think the obvious reason is that if linux is an environment that one is used to and familiar with, then it is nice to have linux on the 5mx - a portable linux box as a PDA that meshes nicely with one's linux desktop machine. Another reason is that it is a real linux installation, and one can learn an awful lot about linux by working with the installation, both by installing the system, and by having a portable linux machine handy to play around with. Linux on the 5mx is a linux PDA with a keyboard that runs about 30 hours on two AA batteries (although some of the latest linux PDA are awfully nice and clearly outstrip the 5mx in performance in so many ways...).

I suppose also it is possible that a portable linux machine such as the 5mx could be used for purposes such as data collection or control in environments where a portable machine would be useful, particularly now that the real time clock for the 5mx is working and wake-up alarms can be set. The 5mx can be used to collect GPS data when in the field, for example.

Finally, linux is currently under active development, while the original EPOC environment has stagnated. Although many linux tools just won't run on the 5mx because of resource limitations: memory, video, cpu speed, disk size, which limits what linux can do on the 5mx, often suitable linux equivalents to EPOC functions can be found. And we certainly don't mean to complain about the EPOC operating system. EPOC is magnificent for many things, but limited in others. With linux on the 5mx, one obtains a dual-boot system, hence one gets the best of both worlds.

3.2. What Works, Generally

The team has ported the Linux 2.4.27 kernel to the Series 5mx/5mxPRO (2.4.32 is our development version), created ARLO (the boot loader), and created several initial ramdisks (initrd) for the project. In addition, a number of larger prepackaged distributions based on Debian Woody have been made available for installation on compactflash disks. All hardware devices on the 5mx are supported by kernel 2.4.27 or later to one degree or another.

At the moment, these distributions contain all the basic elements of any linux system: bash, vi (vim), groff, less, man, perl, nawk, bc, dc, lynx (a web browser), ppp, telnet, ftp (ncftp), rsh, ssh, minicom, emacs ("zile", a smaller emacs-type editor is probably preferred), etc . Starting with a basic system, it would be easy, though it would take a little time, to assemble your own custom system. All known systems are based on Debian Linux since this system has the best support for the ARM cpus. New debian arm packages (*_arm.deb, or a slimmer set of packages, *_arm.ipkg) can be downloaded and installed directly using dpkg -i *_arm.deb (or even apt-get), similarly for ipkg. Most people have been pleasantly surprised at how far along the whole OpenPsion project has come. OpenPsion is a fully functional, basic linux system. X11 now works "out of the box." Most of the larger distributions, or most useful systems, are fairly sizeable and so require a compactflash card of 64MB or greater (256+ MB recommended) in size (compactflash cards of several GB in size are now available). Smaller systems based on initrd's can also be found, and they can be quite functional. The system seems to be quite stable - crashes or siezures, etc. are not often reported.

Larger packages such as yorick or octave - numerical computation packages vaguely like matlab - can also probably be installed except that this package required the X libraries, and so it would take up a great deal of space (I think yorick would work in console mode, if one had the space for it.) The gnu compilers can also be installed, and although they have been shown to work fine, they work rather slowly.

3.3. Psion Series 5mx/5mxPRO Specifications

The Series 5mx Pro differs from the 5mx only in having the operating system loaded into RAM and hence upgradable. The Pro series also offers memory options of 24 and 32MB. Ericsson also produced a rebadged version of the Series 5mx called the MC218.

Processor - 32-bit ARM 710T CPU (RISC based), running at 36.864 MHz

Internal Memory - 16, 24, or 32MB RAM

Internal Memory - 10 MB ROM

Removable Disk Type - Type I Compactflash (CF) Disks

   (disks of up to 1+ GB MB have been shown to work)

Display Resolution - 640x240 (Half-VGA)

Display Type - Monochrome touch-screen (16 shades)

Default OS - EPOC (32 bit, multitasking)

Serial Ports - Standard RS232 and SIR Infrared; up to 230400 baud. 

Power - 2 AA batteries, backed up by a CR2032 lithium battery.

   Approx. 30 hrs of operation.  Optional 6V external power.

Screen Backlight

Sound - 1/2 W, 8 ohm loudspeaker  OKI MSM7717 and MSC1192 chipsets.

Microphone - electret with active gain control.

Keyboard - 53 key, QWERTY layout

Size - 172X89X24 mm

Weight - 350g (with 2 AA batteries)

Operating Temperature - 0 to 40 C

3.4. An OpenPsion Screenshot!

Other screenshots can be found HERE.