EPOC is the operating system used in Psion's later palmtop computers, such as the Series 5, 5mx, 7, netBook, and Revo, and does the same job for pocket computers (though much more reliably!) that Microsoft Windows does for the Desktop PC. The EPOC OS is also used in other pocket computers such as the Osaris from Oregon Scientific and Ericsson's MC218.

Symbian is the company behind EPOC, and is a joint effort between Psion (which is where EPOC originated), Motorola, Ericsson, Nokia and Matsushita. The EPOC platform, now commonly known as Symbian, also features in several smartphones such as the Sony Ericsson P800 and Nokia's 7650, which merge the functions of the pocket computer with that of the mobile telephone. At this rate EPOC could become the world's dominant operating system/platform.

EPOC life didn't start with Symbian (the company now responsible for the development of EPOC). It has roots stretching all the way back to 1984 (a long time as far as computers go) when Psion released its then revolutionary Psion Organiser.

Psion, (or should I say, 'PSION'), is an acronym for Potter's Scientific Instruments, so called by its founder David Potter. Though I'm not sure where the 'O' and 'N' came from. Some say it stands for 'Or Nothing' and others say it's just to make the name sound revolutionary in a physics-sounding way. It has a silent 'P' and is pronounced 'sy-on'. You don't get any street cred for pronouncing it 'piss-e-on' these days!

Even though Psion have been hard at work, releasing their Series 5mx, Series 7, netBook, and Revo within a relatively short period, they're still pushing ahead with the Symbian joint venture. Unfortunately Psion have pulled out of the domestic market, but they remain strong in the corporate sector.