PC Floppy Copy Protection: Vault Prolok

This is Part 4 of a series on PC floppy copy protection methods. You can read the previous parts here: Part 1, covering Formaster Copy-Lock Part 2, covering Softguard Superlok Part 3, covering EA Interlock Vault Corporation Vault was conceived in 1979 and incorporated in 1983. There's not much information about the early days of the company, but 1983 was a busy year for them. The trademark filing…