A C90 cassette has room for, amazingly, 90 minutes - 45 minutes on each side. The physical tape has space for 4 'lanes' of ferromagnetic recording - stereo left and right on side A, and left and right on side B.
A 4-track cassette recorder uses all four lanes on the same 'side', giving 45 minutes. But in runs the tape at double speed, giving you about 22 minutes.
So the longest piece of music I could compose would be about 22 minutes long. So that's what I did, and this piece is a 4 minute excerpt of one of my 'epics'.
I was getting into ambient music, much influenced by The Orb, and this one breaks ground in having...no drums at all.
This must have been about 1992, because about then I managed to get...MIDI! I hacked a sequencer program to replace onboard sounds with my own samples, and made 5 or 6 albums with it. Almost nothing from which escaped the memory hole.
But it's okay, because although the playing was much better, and the sound quality improved, most of it was decidedly ordinary, and didn't feel like making music by hand anymore.