The Atari ST was part of the 16/32 bit generation of home computers, based on the Motorola 68000 CPU, with 512 KB of RAM or more, and 3½" double-sided double-density floppy disks as storage (nominally 720 KB). It was similar to other contemporary machines which used the Motorola 68000, the Apple Macintosh and the Commodore Amiga. Although the Macintosh was the first widely available computer with a graphical user interface (GUI), it was limited to a monochromatic display on a smaller built-in monitor. Preceding the Amiga's commercial release by almost two months, the Atari ST was the first computer to come with a fully bit-mapped color GUI, using a version of Digital Research's GEM released that February. It was also the first home computer with integrated MIDI support.