Over the weekend, I discovered the High Voltage SID Collection, and as a result have had the tunes from half-remembered Commodore 64 games stuck in my head for the last twenty-four hours.

Particularly: Wizball, Marble Madness, Commando and the much less well-known “Dragons Den” which came on a cartridge with the computer itself and was, for quite a while, the only game we owned that we hadn't typed in ourselves from a book.

I also learned that my earliest memories of home-computer sampled sound were the result of a bug in the C64’s sound chip being exploited by clever programmers:

Due to imperfect manufacturing technologies of the time and poor separation between the analog and digital parts of the chip, the 6581's output (before the amplifier stage) was always slightly biased from the zero level. By adjusting the amplifier's gain through the main 4-bit volume register, this bias could be modulated as PCM, resulting in a "virtual" fourth channel allowing 4-bit digital sample playback. The glitch was known and used from an early point on, first by Electronic Speech Systems to produce sampled speech in games such as Impossible Mission (1983, Epyx) and Ghostbusters (1984, Activision). – MOS Technology SID, Wikipedia

So there’s your totally useless information for Monday.