Scream Tracker

Scream Tracker is a tracker (an integrated multi-track step sequencer and sampler as a software application). It was created by Psi (Sami Tammilehto), one of the founders of the Finnish demogroup Future Crew. It was written in C and assembly language.
The first version (1.0) had monophonic 4-bit output via PC speaker and 8-bit via a digital-to-analog converter on the parallel port, or a Sound Blaster 1.x card. The first popular version of Scream Tracker, version 2.2, was published in 1990. Versions prior to 3.0 created STM (Scream Tracker Module) files, later ones used S3M (ScreamTracker 3 Module). The last version of Scream Tracker was 3.21 released in 1994. It was the precursor of the PC tracking scene and its interface inspired newer trackers like Impulse Tracker.
"Scream Tracker" 3.0 and later supports up to 99 8-bit samples, 32 channels, 100 patterns and 256 order positions. It can also handle up to 9 FM-synthesis channels on sound cards using the popular OPL2/3/4 chipsets, and unusually, can play PCM samples and FM instruments at the same time. There are channels referred to as R1..8, L1..8 and A1..9 to be assigned to those 32 ones, which gives an effective amount of only 25 channels. Panning is free (16 positions by S8x command) only on the Gravis Ultrasound, on which in turn isn't possible to use the A channels, unless an AdLib card is mounted too.
Future Crew released third version (ST3) in 1994, placing it in competition with FastTracker 2. Various other trackers (such as Impulse Tracker or OpenMPT) adopted the use of the Scream Tracker's S3M format.