Diagnostic Processor
Each brick has a diagnostic processor
- Goal: small, independent, trusted piece of hardware running hand-verifiable monitoring/control software
- monitoring: connects to motherboard SMbus, CAN bus
- environmental monitor, CPU watchdog
- control
- reboot/power-cycle main CPU
- inject simulated faults: power, bus transients, memory errors, network interface failure, ...
Not-so-small embedded Motorola 68k processor
- provides the flexibility needed for research prototype
- still can run just a small, simple monitoring and control program if desired (no OS, networking, etc.)