There is another story there about someone writing assembler program calculating 50000! for a DEC PDP-10. The PDP-10's registers are memory mapped to locations

There is another story there about someone writing assembler program calculating 50000! for a DEC PDP-10. The PDP-10's registers are memory mapped to locations 0..15, so you could write a program that ran entirely from the registers. According to the story the registers (which were TTL) overheated and died. I'm old enough to have programmed a PDP-10 when I was at Uni, and yeah once you grok'ed the architecture writing a program that ran in the registers is a challenge you set yourself. Mine computed primes using a sieve. It didn't kill anything.