You're assuming that C runs on the Burroughs the way it commonly does on x86, with arbitrary access to all memory within its address space. This is not specified in the C standard, and it's not the case for C on the Burroughs. In particular, since C was not the OS implementation language, but was mainly uaed to port programs from other architectures, the C heap lived entirely within a single memory block and C code could not interfere with other programs. See: https://en.wikipedia.org/wiki/Burroughs_large_systems_descri...