It is mainly intended to be used with Atari emulators and clones, such as Hatari.
The VDI complies with the ANSI standard X3H3.6CG-VDI
It ran Digital Research’s GEM (Graphical Environment Manager) on Atari’s proprietary TOS (The Operating System). “ST” stands for sixteen/thirty-two, in reference to the 16-bit external bus and 32-bit internals of the 68000 chip. The Atari ST runs on the Motorola 68000 CPU. Heralded as Atari’s flagship graphics machine, it competed against the Commodore Amiga and Acorn Archimedes. The initial model, the 520ST, saw limited release in April–June 1985. The Atari ST is a line of home computers from Atari Corporation and the successor to the Atari 8-bit family.