Opcode, power house Mac MIDI sequencing and audio recording software and MIDI interface hardware for the Mac (although they did make some apps for Windows). They were purchased and totally destroyed by the very special assholes at Gibson Guitars.

Opcode Studio Vision MIDI Sequencer for MacOS Classic

Opcode released their flagship MIDI sequencing software Vision back in 1989 for the Macintosh. Vision was very well received and was on the top of it's game at the time, winning several awards. It was in 1990 however that Opcode gave birth to Opcode Studio Vision.

I have a lots of fond memories of hours upon hours spent in Studio Vision. Studio Vision stood out as the first MIDI sequencer to integrate digital audio recording. It was the first sequencer that i ever owned (software or hardware) and served me well starting back in 1991 on my old Mac IIci.