Pathfinder(lander): RAD 6000, 32 bit, 5.0 MIPS nominal, 2M byte EEPROM, 128M bytes DRAM mass memory. The code was developed using VxWorks as the real-time OS and "C" and assembly languages. It utilizes object-oriented constructs.

Sojourner(rover): 80C85 with a 2MHz clock rated at 100KIPS. It uses 176Kbytes of PROM and 576Kbytes of RAM. Sojourner's software was written in C and assembly using a Unix development environment (note: Sojourner has no on-board operating system)

The rovers (Spirit & Opprtunity) run a VxWorks embedded operating system on a radiation-hardened 20 MHz RAD6000 CPU with 128 MB of DRAM with error detection and correction and 3 MB of EEPROM. Each rover also has 256 MB of flash memory.