Today, it’s not rare to pick up a music CD and be treated to special content, some better than others of course. It gives people more incentive to spend their ~$15 on the disc and makes it feel like a complete package. However, according to this article, this is nothing new. It actually began in the vinyl days.
The process was actually quite simple. Record a portion of the record to a cassette tape, load that tape into your Spectrum computer and see if the game would work. This wasn’t a rare feature either, the article mentions many LPs that had this functionality.
Most of these programs were written for the Sinclair Spectrum home computer series. The Sinclair Spectrum was a relatively cheap home computer system that used a television set as a monitor and loaded programs from tapes. It thrived in England in the early 80’s.
Source: Kempa – Via: Boing Boing