Editing Atari ST (section)

=== Operating system ===
Soon after the Atari buyout, [[Microsoft]] suggested to Tramiel that it could port [[Microsoft Windows|Windows]] to the platform, but the delivery date was out by two years.<ref name="3years"/> A proposal to write a new operating system was rejected as Atari management was unsure whether the company had the required expertise.<ref name="3years"/>

[[Digital Research]] was working on a new GUI-based system called Crystal, soon to become [[GEM (desktop environment)|GEM]], but was fully committed to the Intel platform. A team from Atari was sent to Digital Research headquarters to work on a port to the 68000. Atari's Leonard Tramiel oversaw "Project Jason" (also known as The Operating System) for the ST series, named for designer and developer Jason Loveman.<ref name="oren">{{cite web|last1=Oren|first1=Tim|title=Professional GEM Column #15|url=http://cd.textfiles.com/crawlycrypt1/program/books/progem/gemdos.15|website=textfiles.com|publisher=Antic Publishing|date=1986}}</ref>

GEM is based on CP/M-68K, a direct port of [[CP/M]] to the 68000. By 1985, CP/M was becoming increasingly outdated; it did not support subdirectories, for example. Digital Research was also in the process of building GEMDOS, a [[disk operating system]] for GEM, and debated whether a port of it could be completed in time for product delivery in June. The decision was eventually taken to port it, resulting in a [[GEMDOS]] file system which became part of [[Atari TOS]] (for "The Operating System", colloquially known as the "Tramiel Operating System"). This gave the ST a fast, [[hierarchical file system|hierarchical]] [[file system]], essential for [[hard drives]], and provided programmers with function calls similar to [[MS-DOS]]. The [[Atari ST character set]] is based on [[codepage 437]].