Wednesday, November 16, 2005

A blast from the past

Back in the 80's, 8-bit computers still were rare items found in a household.
Putting processing limitations aside, their capabilities could also be considered "marginal" by today's standards.

Still, necessity really is the mother of invention.

Imagine a simple flip-flop IC whose output is connected to a speaker via a small amplifier transistor. Each time the computer addresses a particular memory location, the flip-flop toggles, causing the speaker to "click". Do that many times per second and you'll end up generating beeps of varied frequencies and durations.

This was the primary sound circuit found on the venerable Apple II computer, but do not let its simplicity fool you.

Because such beasts also had limited memory capacities, the best way to make the best possible use of available memory and processing power was to write programs in assembly language. Small and fast, yet very difficult to debug.

Nonetheless, geniues like Paul Lutus managed to push the simple beep generator to the limit by making subtle alterations to the click timing loop. The results were astounding: multiple voices (up to 4) with some variations in timbre.

Shortly after that, specialised music hardware began to appear either integrated into the computer's motherboard (like the SID chip in the C=64) or as add-in cards (the Mockinboard for the Apple II). The main CPU could dedicate its attention to more important tasks instead of wasting precious clock cycles in timing loops.

It was in this scenario that Demo Coders appeared. Pushing things to the limit and then some, the main objective was to do as much as possible (graphics, sound) in as little memory space as possible.

Some demo coder groups disappeared while others prevailed. Today I found one of them, specialised in music and as creative as ever:

Vibrants homepage

Listen to their music, and think back how things were in the old days and how much they have changed.

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