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00:15, 5 January 2007 DJL (Dave J Looker) was the author of the [[Speedlock]] protection system, used on many cassette games released in the UK. Speedlock was a modified version of the [[Spectrum]]'s cassette routines with protection added.
As the protection system continued to evolve, programs such as [[Soft-Lok]] and the [[Bonzo]] suite were upgraded to break the protection.
A separate disc protection system, [[8k Speedlock]], relied on the fact that the CPC's hardware could reliably read but not write 8k sectors. To get around this, the [[Executioner]]'s utility [[Xexor]] included a 'brain file' solution to crack individual games before copying them.