Compiling an application for use in highly radioactive environments

Question

We are compiling an embedded C++ application that is deployed in a shielded device in an environment bombarded with ionizing radiation. We are using GCC and cross-compiling

Answer 1

This is an extremely broad subject. Basically, you can't really recover from memory corruption, but you can at least try to fail promptly. Here are a few techniques you could use:

• checksum constant data. If you have any configuration data which stays constant for a long time (including hardware registers you have configured), compute its checksum on initialization and verify it periodically. When you see a mismatch, it's time to re-initialize or reset.

• store variables with redundancy. If you have an important variable x, write its value in x1, x2 and x3 and read it as (x1 == x2) ? x2 : x3.

• implement program flow monitoring. XOR a global flag with a unique value in important functions/branches called from the main loop. Running the program in a radiation-free environment with near-100% test coverage should give you the list of acceptable values of the flag at the end of the cycle. Reset if you see deviations.

• monitor the stack pointer. In the beginning of the main loop, compare the stack pointer with its expected value. Reset on deviation.