For the Apple ][ there was even a card (the “wildcard”) which would interrupt the CPU and dump the memory to disk along with a special loader, allowing you to r

For the Apple ][ there was even a card (the “wildcard”) which would interrupt the CPU and dump the memory to disk along with a special loader, allowing you to reboot from the disk and resume where the CPU left off. I don't think it had any valid use besides defeating copy protection: http://mith.umd.edu/vintage-computers/items/show/11 http://mith.umd.edu/vintage-computers/items/show/11 Oh and I just found this thing called the “Senior PROM” which I’d never heard of before: http://planemo.org/retro/senior-prom-reverse-engineering/ http://planemo.org/retro/senior-prom-reverse-engineering/ Here's some examples of early copy protection techniques: http://www.fadden.com/apple2/cassette-protect.html http://www.fadden.com/apple2/cassette-protect.html