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Apple IIgs

The Apple IIGS (pronounced "Apple two G S") was the last computer model of the Apple II series of personal computers made by Apple Computer. It supported numerous new hardware and software features as well as full compatibility with earlier Apple II models, but Apple paid it relatively little attention as the company increasingly focused on the Macintosh platform.

Table of contents
1 Background
2 Hardware features
3 Software features


The IIGS was released in September 1986 . It competed with personal computers such as the Commodore Amiga and Atari ST at the time of its release and was also popular with schools, but Apple failed to promote and update the IIGS, preferring to focus on the Macintosh instead. This lack of attention caused the IIGS to fall increasingly far behind other personal computers over its lifetime, and Apple ceased production of it in 1992.

Hardware features

The Apple IIGS was an innovative computer with many improvements over the older Apple IIe and Apple IIc. It used the new Western Design Center 65816 16-bit microprocessor running at 2.8 MHz, which was faster than the 8-bit 6502 and 65C02 processors used in earlier Apple IIs and also allowed the IIGS to use more RAM. It also included enhanced graphics and sound, wihch led to its name. The graphics of the IIGS were the best of the Apple II series, with new Super High Resolution (SHR) video modes. These included a 640x200-pixel mode with two-bit palletized color and a 320x200-pixel mode with four-bit palletized color. It also provided built-in sound thanks to an onboard Ensoniq audio chip capable of supporting stereo sound (although an adaptor card was needed to connect stereo speakers).

The IIGS could support both 5.25-inch and 3.5-inch floppy disks and, like the IIe before it, had several expansion slots. These included seven general-purpose expansion slots compatible with those on the Apple II, II+, and IIe, plus a memory expansion slot that could be used to add up to 8 MB of RAM. The IIGS, like the IIc, also had dedicated ports for external devices. These included a port to attach floppy disk drives, two serial ports for devices such as printers and modems (which could also be used to connect to a LocalTalk network), an Apple Desktop Bus port to connect the keyboard and mouse, and composite and RGB video ports.

Hardware revisions

Although Apple never introduced a substantially enhanced version of the IIGS after its initial release, it did create several slightly revised hardware versions.

Hardware versions from ROM 01 onward display the ROM version on the bottom of the screen when starting up.

Expansion capabilities

The IIGS was highly expandable. The expansion slots could be used for a variety of purposes, greatly increasing the computer's capabilities. SCSI host adaptors could be used to connect external SCSI devices such as hard drives and CD-ROM drives. Other mass storage devices such as adaptors supporting internal 2.5-inch IDE hard drives could also be used. Another common class of expansion cards was accelertor cards replacing the computer's original processor with a faster one. A variety of other cards were also produced, including ones allowing new technologies such as 10BASE-T Ethernet and CompactFlash cards to be used on the IIGS.

Development and codenames

Apple's first internal project to develop a next-generation Apple II based on the 65816 was known as the "IIx." The IIx project, though, became bogged down when it attempted to include various coprocessors allowing it to emulate other computer systems. Early samples on the 65816 were also problematic. These problems led to the cancellation of the IIx project, but somewhat later a new project was formed to produce an updated Apple II. This project, which led to the released IIGS, was known by various codenames while the new system was being developed, including "Phoenix," "Rambo," "Gumby," and "Cortland."

Software features

Broadly speaking, 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-specific software, most of which runs under the Apple IIGS System Software and takes advantage of its advanced features, including a Macintosh-like graphical user interface.

8-bit Apple II compatibility

The Apple IIGS was almost completely backward compatible with older Apple II computers, so users wouldn't be left with large libraries of useless software. The IIGS could run all of Apple's earlier Apple II
operating systems: Apple DOS, ProDOS 8, and Apple Pascal. It was also compatible with nearly all 8-bit software running under those systems. Like the Apple II+, IIe, and IIc, the IIGS also included Applesoft BASIC and a monitor (which could be used for very simple assembly language programming) in ROM, so they could be used even with no operating system loaded from disk.

Apple IIgs System Software

The Apple IIGS System Software utilized a Graphical user interface (GUI) very similar to the Apple Macintosh's and somewhat like
GEM for PCs and and the operating systems of contemporary Atari and Amiga computers. Initial versions of the System Software were based on the ProDOS 16 operating system, which was based on the original ProDOS operating system for 8-bit Apple II computers. Although it was modified so that 16-bit Apple IIGS software could run on it, ProDOS 16 was written largely in 8-bit code and did 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 GS/OS. It better utilized the unique capabilities of the IIGS and included many valuable new features. The Apple IIGS System Software was substantially enhanced and expanded over the years during which it was developed, culminating in its final version, System 6.0.1, which was released in 1993.

Graphical user interface

The IIGS System Software provided a
mouse-driven graphical user interface using concepts such as windowss, menus, and icons. This was implemented by a '"toolbox" of code, some of which resided in the computer's ROM and some of which was loaded from disk. The IIGS GUI was very similar to that of early Macintoshes. One major application could run at a time, although other smaller programs known as Desk Accessories could be used simultaneously. The IIGS had a Finder application very similar to the Macintosh's, which allowed the user to manipulate files and launch applications. By default, the Finder was displayed when the computer started up and whenever the user quit an application that had been started from it, although the startup application could be changed by the user.

The IIGS Finder allows easy exploration of disks' contents. New Desk Accessories such as the Calculator can be run at the same time as applications such as the Finder.


The IIGS System Software could be extended through various machanisms. New Desk Accessories were small programs ranging from a calculator to simple
word processors that could be used while running any standard desktop application. Classic Desk Accessories also served as small programs available while running other applications, but they used the text screen and could be accessed even from non-desktop applications. Control Panels and initialization files were other mechanisms that allowed various functions to be added to the system. Finder Extras permitted new capabilities to be added to the Finder, drivers could be used to support new hardware devices, and users could also add "tools" that provided various functions that other programs could utilize easily. These features could be used to provide features never planned for by the system's designers, such as a TCP/IP stack known as "Marinetti."

See also: Apple II family