I laugh at your DRM and present – the Lenslok

Continuing my nostalgia kick, I was thinking about copy protection in the world of 8 bit computers.  Games for the ZX Spectrum and the Commodore 64 were on audio tape, recorded as sound (in Europe, in the US I think the Commodore was more commonly used with diskettes).  Anyway, this presented an excellent opportunity for up and coming software pirates (aka kids with only a small amount of pocket money).  One kid would buy the game, and then it was easy using tape-to-tape copying to give your friends copies as well.

This resulted in a number of counter measures, in a software piracy war that would continue until the present day.  But in those days, it was a far less technical war.  There were a number of methods introduced.  For the ZX Spectrum, different modulations were tried with the tape content, essentially trying to ensure that only original recordings were of the right quality to load, while copies of the audio would fail.  This was less successful than hoped, as tape-to-tape copying equipment developed rather quickly as well.  Some schemes only worked because it wasn’t easy to share information around quickly, for example, Jet Set Willy was supplied with a colour card and in order to play, you needed to enter the colour corresponding to a prompt.

While it was hard to create colour photocopies at the time, and not exactly trivial to write up and share a full list of the colours, it turned out to be rather easy to circumvent the copy protection and the solution was actually published in a magazine at the time (Your Computer, Issue 6, June 1984).  It was a different age back then.

However, for many Spectrum owners, the most frustrating scheme was the Lenslok.  Anyone who had the necessity to use them knew how unreliable they were, and they quickly became one of the most hated copy protection schemes around – not because it worked – but because even for legitimate owners, it sometimes didn’t work.  That’s a lesson for the DRM boys.  The Lenslok was a plastic prism, which you used to unscramble text on the screen before entering it to play the game (most notably, Elite).  However, it had to be calibrated to your TV every time (to get the size right) and wasn’t the easiest thing in the world to use.

And it still didn’t provide 100% reliable protection, because interfaces for the Spectrum allowed people to save games to tape at a point past the copy protection scheme and share them with their friends anyway – just another failed copy protection scheme from the games industry.

So when you curse your DRM, or laugh at the attempts to fix a social issue with a technical solution, just think back to those of us squinting at our black and white TV screens from an inch away, through a plastic prism, so we could play an 8 bit pre-cursor to Modern Warfare 2.

2 thoughts on “I laugh at your DRM and present – the Lenslok”

  1. Excellent post.

    Although I can’t remember this particular piece of plastic, tape modulation and a rotating wheel for Monkey Island do spring to mind. I wonder if it’ll ever stop?


    1. Ahh the rotating wheels, I’d forgotten those. I had a photocopied one so I could play Monkey Island after losing my original.

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