What kind of an embedded system sits inside a mars rover?

The various tasks you refer to are distributed across a number of cards. As others have answered, the flight computer itself is a RAD750 from BAE. The majority of the remaining hardware was custom designed at JPL. read more

I worked on other systems than Mars missions. Any system will be custom with flight qualified components with radiation and thermal and other mission requirements. Some of the stuff approved for Mil-SPEC can be used. read more

The stunning success of the Curiosity Mars rover has emboldened NASA to have another go. The US space agency has announced plans to send a new robotic explorer to the Red Planet in 2020. This rover will have the same chassis as Curiosity and a duplicate sky crane will lower it to the surface. read more