Speedlock is the name of a disc and cassette copy protection designed by Dave Looker (DJL) and Dave Aubrey-Jones. Earlier versions mentioned DJL Software later versions mentioned "Speedlock Associates".
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== Cassette ==
It was a modified version of the Spectrum's cassette routines with protection added. It is often recognised for it's blue/black stripes in the border during loading. Later versions had multicoloured stripes for the leader/pilot tone, and then blue/black stripes for the data.
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== Disc ==
Speedlock was also available in disc version. One version called "8k Speedlock", relied on the fact that the CPC's hardware could reliably read but not write 8k sectors.