Amiga is a family of personal computers produced by Commodore from 1985 until the company's bankruptcy in 1994, with production by others afterward. The original model is one of a number of mid-1980s computers with 16-bit or 16/32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphics and audio compared to previous 8-bit systems. These include the Atari ST—released earlier the same year—as well as the Macintosh and Acorn Archimedes. The Amiga differs from its contemporaries through custom hardware to accelerate graphics and sound, including sprites, a blitter, and four channels of sample-based audio. It runs a pre-emptive multitasking operating system called AmigaOS.