Originally Posted by DansSlk

Just the navi processor you mean then mate or are you talking about the headunit.

Its not only Harman that makes these units remember Siemens produces them also

OK mate having a quick look got the page for the S class loaded on the machine at the moment its running Microsoft Windows CE Automotive 4.2 as of its latest software release the new C class is also running the same, the older S that used COMAND 2.0 does not show what it runs maybe that could be the OS you mentioned?

Just as a side note this version of CE is also running on -

All iDrive BMW's
Volvo's from 02 onwards
Mitsubishi's and Subaru's again from 02
Toyota G-BOOK cars
Aston Martin AMV8 DB9 and Vanquish
Fiat and Alfa