Macintosh 512K M0001 WP incl. system disk, Mac software, extra floppy drive, Keyboard, mouse, original Apple Bag and Macintosh book! The Macintosh 512K is a personal computer that was designed, manufactured and sold by Apple Computer, inc. from September 1984 to April 1986. It is the first update to the original Macintosh 128K. It was virtually identical to the previous Macintosh, differing primarily in the amount of built-in random-access memory. The increased memory turned the Macintosh into a more business-capable computer and gained the ability to run more software. The Mac 512K originally shipped with Macintosh System 1.1 but was able to run all versions of Mac OS up to System 4.1. It was replaced by the Macintosh 512Ke and the Macintosh Plus. All support for the Mac 512K was discontinued on September 1, 1998.