But the macros were the least of its problems: It allocated memory by trapping SIGSEGV (SIGnal for SEGmentiation Violation; that is, the signal the OS sends a program when it's tried to access memory beyond the region it owns); the function which caught SIGSEGV allocated more RAM. This made it difficult to port sh to the Motorola 68000-based computers which were the first generation of Unix workstations.
