All necessary memory is allocated at initialization. The application is not allowed any allocations during it's normal runtime. This is how it avoid memory bugs.

Not a lot of people write programs this way.

A number of commenters have pointed out static allocation, but none mentioned TigerBeetle's sophisticated testing suite, which is more relevant.

See here for a post on their deterministic simulation harness: https://tigerbeetle.com/blog/2023-07-06-simulation-testing-f...