Editing Apple IIGS (section)

== Software features ==
Software that runs on the Apple IIGS can be divided into two major categories: 8-bit software compatible with earlier Apple II systems such as the IIe and IIc, and 16-bit IIGS software, which takes advantage of its advanced features, including a near-clone of the Macintosh [[graphical user interface]].

=== 8-bit Apple II compatibility ===
Apple claimed that the IIGS was 95% compatible with contemporary Apple II software. One reviewer, for example, successfully ran demo programs that came on cassette with his 1977 Apple II.{{r|chien198704}} The IIGS can run all of Apple's earlier Apple II [[operating system]]s: [[Apple DOS]], [[Apple ProDOS|ProDOS]] 8, and [[Apple Pascal]]. It is also compatible with nearly all 8-bit software running on those systems. Like the Apple II+, IIe, and IIc, the IIGS also includes [[Applesoft BASIC]] and a [[machine-language monitor]] (which can be used for very simple [[assembly language]] programming) in ROM, so they can be used even with no operating system loaded from disk. The 8-bit software runs twice as fast unless the user turns down the processor speed in the IIGS control panel.

=== System software ===
Early versions of the system software are based on the [[Apple ProDOS|ProDOS]] 16 operating system, which is based on the original ProDOS operating system for 8-bit Apple II computers. Although it was modified so that 16-bit Apple IIGS software can run on it, ProDOS 16 was written largely in 8-bit code and does not take full advantage of the IIGS's capabilities. Later System Software versions (starting with version 4.0) replaced ProDOS 16 with a new 16-bit operating system known as [[Apple GS/OS|GS/OS]]. It makes better use of the unique capabilities of the IIGS and includes many valuable new features. The IIGS System Software was substantially enhanced and expanded over the years during which it was developed, culminating in its final official version, System 6.0.1, which was released in 1993. In July 2015, members of a computer group from France released a new, though unofficial, version of that System Software, dubbed "System 6.0.2" (and later followed by System 6.0.3 and 6.0.4), that primarily fixed some bugs.<ref name="HeiseOnline">{{cite web|url=http://www.heise.de/newsticker/meldung/System-6-0-2-fuer-den-Apple-IIgs-erscheint-nach-22-Jahren-2753504.html|title=System 6.0.2 für den Apple IIgs erscheint nach 22 Jahren|author=Schwan|first=Ben|date=July 20, 2015|publisher=Heise Online|language=de|trans-title=System 6.0.2 for the Apple IIgs appears after 22 years|access-date=June 8, 2016|archive-date=June 7, 2016|archive-url=https://web.archive.org/web/20160607014123/http://www.heise.de/newsticker/meldung/System-6-0-2-fuer-den-Apple-IIgs-erscheint-nach-22-Jahren-2753504.html|url-status=live}}</ref>

=== Graphical user interface ===
Similar to the Mac, the IIGS provides a [[computer mouse|mouse]]-driven graphical user interface. This is  implemented by a "toolbox" of code, some of which resides in the computer's ROM and some of which is loaded from disk. Only one major application can run at a time, although other, smaller programs, known as [[Desk Accessories]], can be used simultaneously. The IIGS has a Finder [[file manager]] application very similar to the Macintosh's, which allows the user to manipulate files and launch applications. By default, the Finder is displayed when the computer starts up and whenever the user quits an application that is started from it, although the startup application can be changed by the user.

=== Multitasking ===
A third party [[UNIX]]-like [[computer multitasking|multitasking]] [[kernel (operating system)|kernel]] was produced, called [[GNO/ME]], which runs under the GUI and provides [[preemption (computing)|preemptive]] multitasking. In addition, a system called ''The Manager'' can be used to make the Finder more like the one on the Macintosh, allowing major software (other than just the "accessory" programs) to run simultaneously through [[cooperative multitasking]].