Base porting

However, it is possible to use
Symbian OS with virtually any hardware(such as ARM, MIPS, ...) platform by fitting the operating
system to the new platform (called base porting). It also means that
for the same type of hardware – actually, even for exactly the same
hardware – it is possible to fit many of these smartphone operating
systems.

 

From <Programming for the Series 60 platform and Symbian OS> P5