SymbianSymbian, formerly known as EPOC32, the OS at the heart of PSION hardware and an increasing number of telephony, telecommunication, PDA, etc. products. A very classical and absolutely uninventive architecture, but that is well respected and stable.
It is the progression of the SIBO operating system (found on Psion Siennas and Psion 3 devices), upgraded to the EPOC (for 3mx, 5mx, and series 7 Psions).
Current version (as of 2003) is Symbian 7. Nokia uses the Symbian OS version 6 with 2 versions of it on the Market. The series 60 version on devices such as the Nokia 3650 and 7560, and the version that exists on the Nokia 9210/9290 models.
SonyEricsson uses the symbian 7 Quartz for it's P800 smartphone. 0wned