powerpc 750

Interesting IAmA on reddit with the Mars Curiosity team. Lots of great stuff but being a programmer this caught my eye:

You are right that the processor does feel acient. Our current smarthphones are more powerful. The reasoning for this is three-fold. First of all, the computer was selected about 8 years ago, so we have the latest and greated space certified parts that existed then. Second of all, it was the most rubost and proven space grade processor at that time. Thirdly, in order to make a processor radiation hardened it requires lots of tricks on the silicon that is not conducive to making it fast. Given that, it does not run any GUIs and can just focus on raw programming, and actually gets a lot done. All of the programming is done in C, and our toolchain is very similar to programming on any platform.

-JG (presumably Jonny Grinblat aka “Pre-celebration Guy” – Avionics System Engineer)

I did mention a few days ago specifically about the CPU and how it’s really similar to the Power Mac G3’s of the late 90’s.

I’ve said it once today, and I’ll say it again:

Realization: No matter what I do today, it won’t be as awesome as landing a 1 ton robot on Mars with a space crane.

Curiosity is the pinnacle of science and if it’s predecessors (Spirit and Opportunity) are any indication will have a long life of helping us explore Mars.

A neat little side note is that the processor of choice in the rover is a RAD750. Which is based on the PowerPC 750, aka the PowerPC G3. When you look at the specs, you’ve got to admit, it looks a lot like those G3 Mac’s (except they used spinning disks and not flash storage back then):

On-board memory includes 256MB of DRAM and 2 GB of Flash Memory both with error detection and correction and 256kB of EEPROM.

A neat little tidbit. This rover’s close relative was my desktop computer in High School.