Prolok was a copy protection system developed by W. Krag Brotby and Vault Corporation in 1982. Prolok was involved in the copyright law case Vault Corp. v. Quaid Software Ltd. which allowed software to be used in certain situations that the copyright holder did not originally intend. Prolok was developed for

Apple II The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...

CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/ 85-based microcomputers by Gary Kildall of Digital Research, Inc. Initial ...

CP/M-86 CP/M-86 was a version of the CP/M operating system that Digital Research (DR) made for the Intel 8086 and Intel 8088. The system commands are the same as in CP/M-80. Executable files used the relocatable .CMD file format. Digital Research als ...

, MS-DOS,

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

and OS/2. US Patent 4,785,361

References

Copy protection 1982 software {{technology-stub