Adventures in PC Emulation

This is part 5 of a series of articles investigating various floppy copy-protection schemes seen on the IBM PC platform. You may wish to read the previous entries in this series: Part 1, covering Formaster Copy-Lock Part 2, covering Softguard Superlok Part 3, covering Electronic Arts Interlock Part 4, covering Vault Prolok XEMAG was a commercial disk duplicator that provided services to companies such as Electronic Arts, Activision, IBM, Ashton-Tate, and Oracle. XEMAG traces its origins to the disk duplication department of Peripheral Marketing, Inc., from which it was spun-off in 1983. By 1983 they were duplicating a million floppies a month.  Reproduction of a design appearing on some XEMAG swag   For some background into what working at XEMAG was like, you may wish to read  this interview with Peter Brown, a former XEMAG employee. XEMAG was acquired by the Xidex Magnetics Corporation  in February of 1983, for $3.78 million . Xidex would then acquire disk manufacturer Dysan  in ear

This post goes hand-in-hand with my article on Vault Corporation's Prolok copy-protection technology . Perhaps the most important historical legacy of Vault Corporation results from the lawsuit they initiated against Quaid Software, makers of the backup software CopyWrite. CopyWrite was capable of duplicating Prolok-protected diskettes with the help of a bundled utility called RAMKEY. Vault sued Quaid Software seeking an injunction and $100 million in damages. The resulting court case, Vault Corporation vs Quaid Software , was decided in Quaid's favor and established an important legal precedent protecting the rights of end users to make backup copies of their software without restriction. Robert McQuaid, founder of Quaid Software, was kind enough to agree to the following interview. How did you decide that Quaid Software would target the software backup business?  You could have done something less exciting, like make a spreadsheet or database program. I was in touch with a s

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 for Prolok, their first copy-protection product has a first-use date of March 1983. That same year would see several full-page, color advertisements in various PC magazines, making them one of the major competitors of firms like Softguard . Compared to the modest back-page adverts from other copy-protection firms, Vault's advertisements were very slick - clearly put together by a professional ad agency. One of Vault's biggest customers was  Ashton-Tate , makers of the industry-leading  dBase  database software and later owners of the  Framework  office suite. Both dBase III v1.0