The Atari ST was basically a “home/personal computer that was commercially popular from 1985 to the early 1990s. The “ST” officially stands for “Sixteen/Thirty-two”, which referred to the Motorola 68000’s 16-bit external bus and 32-bit internals.” Videos after the jump,.
The Atari ST was the first computer with a fully bit-mapped color GUI. It had an innovative single-chip graphics subsystem (designed by Shiraz Shivji) which shared the full amount of system memory, in alternating clock cycles, with the processor, similar to the earlier BBC Micro and the Unified Memory systems that have become common today. It was also the first home computer with integral MIDI support