Challenges of Getting to Mars: Curiosity's 7 Minutes of Terror

Hardware

Main computer. RAD750, a single-board computer (motherboard, RAM, ROM, and CPU) produced by BAE. The RAD750 has been on the market for more than 10 years, and it’s currently one of the most popular on-board computers for spacecraft. In Curiosity’s case, the CPU is a PowerPC 750 (PowerPC G3 in Mac nomenclature) clocked at around 200MHz — which might seem slow, but it’s still hundreds of times faster than, say, the Apollo Guidance Computer used in the first Moon landings. Also on the motherboard are 256MB of DRAM, and 2GB of flash storage — which will be used to store video and scientific data before transmission to Earth.

The RAD750
*temperature range: -55 and 70C,
*radiation levels up to 1000 gray.

Software

27-year-old VxWorks operating system. VxWorks, developed by Wind River Systems (which was acquired by Intel), is a real-time operating system used in a huge number of embedded systems. The previous Mars rovers (Sojourner, Spirit, Opportunity), Mars Reconnaissance Orbiter, and the SpaceX Dragon spacecraft all use VxWorks. VxWorks also powers BMW iDrive, the Apache Longbow helicopter, and the Apple Airport Extreme and Linksys WRT54G routers (really).
I said that VxWorks is 27 years old, but that’s a bit unfair: The initial release was in 1985 (around the same time as MS-DOS 3.0), but it has been in constant development since then, reaching v6.9 last year. Why does Curiosity use VxWorks? It’s reliable, has a mature development toolchain, and presumably its low-level scheduling and interrupt systems are ideal for handling real-time tasks like EDL (entry, descent, and landing; aka, seven minutes of terror).


Source :

http://www.extremetech.com/extreme/134041-inside-nasas-curiosity-its-an-apple-airport-extreme-with-wheels