MTM format
The module format of MultiTracker, an early PC tracker offering up to 32 channels while the Amiga still had four.
MultiTracker arrived in 1993 from the group Renaissance, the same crowd that had given the PC Composer 669 the year before. Files used the .mtm extension and stored tracks separately from patterns, so one channel's worth of notes could be reused across several patterns — a thrifty layout that set it apart from MOD.
It never really caught on. Scream Tracker's S3M and FastTracker's XM landed at roughly the same time and were both more stable and richer in effects, which left MTM as a waystation on the PC scene's road away from its Amiga inheritance. Modern players such as OpenMPT still read it.