Opcode have been in the sequencer business for a long time. At the back of my floppy disk archive, in the section that will soon be 10 years old, there's a disk containing a demo of Vision 1.02 from 1989. The original Opcode sequencer from 1986 was called exactly that (Opcode Sequencer), and was very much a mixture of live performance aid and MIDI sequencer, whilst in 1989 the addition of the now universal piano-roll graphical display prompted a change of name for the program, to Vision -- so now you know! Just one year later, the first version of Studio Vision was released, and this added digital audio recording features, which were revolutionary at the time.
Studio Vision Pro offers a near-seamless integration of MIDI and audio sequencing. This update cleans up a few rough edges, and adds many neat refinements.
Opcode sequencers are designed around patterns -- in some ways they're rather like overgrown drum machines. The 'Song' is the basic container -- what you store on disk. A Song is made up of one or more Sequences, and these Sequences can be the sections of the song: Intro, Verse, Chorus, and so on. Within a Sequence are individual Tracks, and these Tracks can themselves be made up of smaller units called Segments. You can re-use Segments in several Sequences if you like.