Lisa OS

Lisa OS

The Lisa operating system features protected memory, enabled by a crude hardware circuit compared to the Sun-1 workstation (c. 1982), which features a full memory management unit. Motorola did not have an MMU (memory-management unit) for the 68000 ready in time, so third parties developed their own. Apple's is also the result of a cost-cutting compromise, with sluggish performance. Based, in part, on elements from the Apple IIISOS operating system released three years earlier, Lisa's disk operating system also organizes its files in hierarchical directories. File system directories correspond to GUI folders, as with previous Xerox PARC computers from which Lisa borrowed heavily. Lisa was designed around a hard drive, unlike the first Macintosh.