According to the Peter Coffee's July 21 PC Week column, NASA chose to use a beta version of VxWorks with the R6000. As a result, they had problems with stack management and pointers during task switching which is most likely why the machine has continually rebooted itself when too many tasks were going in parallel. They got what the paid for with COTS in this instance. Darren Davenport ______________________________ Reply Separator _________________________________ Subject: Re: Ada goes to Mars (maybe) Author: "Panfil, Thomas A." <[log in to unmask]> at CCGATE Date: 7/24/97 4:57 PM I think that our friend from JPL simplified the hardware description to put it into a commonly known context. I suspect that the processor he really considers using is the RAD6000 which is currently in use on the ongoing exploration by the "Mars Pathfinder Mission." Per a 14 July 1997 Federal Computer Week article entitled "COTS in Space": "..... One of the main components of the mission is the on-board processor that guided the Pathfinder Lander's journey to Mars, controlled its landing, and now governs its operation from the planet's surface. The processor, a radiation-hardened version of IBM Corp.'s 32 bit-RISC System/6000, was adapted for the mission by Lockheed Martin Federal Systems in Manassas, VA. The chip is the first radiation-hardened commercial processor to guide a NASA mission. The RAD6000, as it was renamed by Lockheed, was responsible for crucial elements of the flight to Mars such as cruise altitude control. The chip also managed the lander's entry events, including deploying the parachutes and air bags that cushioned the Lander's fall to Mars. ..... Despite its radiation-hardened state, the commercial version of the processor provides the Pathfinder mission with 22 MIPS of processing power. The RAD6000 can provide an unprecedented space throughput of up to 35 MIPS, ... In addition to the processor, the flight computer contains a sealed memory unit that also uses off-the-shelf technology, with tweaks to allow it to survive the energy particles. Although the mission required 128M of dynamic RAM, this type of memory space is not available in the hardened state, ... The processor's memory unit detects any damage done by the particles and heals itself through a special error correction process. ....." News reports typically seem to have some garbles, and can't provide all details. This one doesn't mention the bus or the OS used, but some IBM RISC System/6000 machines are called "PowerPCs". ooooooooo oooo oooooo ooooo oooo oooo ooo oo o o o _||______________----- ____________ ____________ ____---____ / __ _ _ _ \[]|/ Ada95 | |Ada| |83 | | C++ | \|__|_/ \_/ \_/ \\_\_||____________|.|___|__|___|. |_|_______|_|~C //o^o \_/ \_/ \_/ o^o o^o^o o^o^o o^o o^o o^o o^o ======================================================================= Thomas A. Panfil Secretary & Treasurer -- Baltimore SIGAda (301) 498-7313