The Commodore 64 supported (or maybe it was the 1541 drive that implemented it) what was called "relative files", which were composed of fixed-size records that

The Commodore 64 supported (or maybe it was the 1541 drive that implemented it) what was called "relative files", which were composed of fixed-size records that were accessed by index. I always thought they sounded cool, but never had a real need for them in my toy projects on that platform.