Editing Apple Lisa (section)

== Operating System and Software ==
[[File:Interface gráfica do computador pessoal Lisa.gif|thumb|Lisa OS GUI]]
=== Lisa OS ===
Lisa OS 1.0 debuted with the hardware. Its WYSIWYG GUI featured overlapping windows, pull-down menus, drag-and-drop icons, and document-centric workflows (e.g., “stationery” templates). Core services provided a protected memory sandbox per application, cooperative multitasking via event-loop scheduling, and a ProDOS-inspired hierarchical file system. Subsequent OS revisions added support for larger RAM configurations and refined UI performance; the final Lisa OS 3.1 was shipped with Lisa 2/10.

=== Microsoft Xenix on Lisa ===
An optional Microsoft Xenix port transformed Lisa into a UNIX-like multi-user system when paired with the RAM expansion and ProFile HDD. Xenix on Lisa supported multiple terminal sessions over serial ports, a Bourne shell, standard UNIX utilities, and software development tools—demonstrating the Lisa’s versatility beyond its GUI orientation.