Apple allowed the computer history to publish the source texts of the operating system lisa os , which was used in personal computers apple lisa . Additionally, the publication and set of applications for LISA OS, such as Lisawrite, Lisacalc, Lisadraw, Lisagraph, Lisaproject, Lisalist and Lisaterminal, is allowed. Code published ( zip archive 1.1 MB) under the license Software License Agreement .
The Lisa OS operating system had advanced characteristics for the OS of the early 1980s, including supported the memory protection system and virtual memory, multitasking, FS with the separation of files by directory (HFS prototype), provided a graphic interface with a set of applications for solving Applied tasks. For development, Pascal language was used.