Apple IIGS
The Apple IIGS is a 16-bit personal computer produced by Apple Computer beginning in September 1986. It is the fifth and most powerful model of the Apple II family. The "GS" in the name stands for "Graphics and Sound", referring to its enhanced multimedia hardware, especially the "state-of-the-art" audio. It is compatible with earlier Apple II models, and Apple initially sold a kit for converting an Apple IIe into a IIGS. 8-bit Apple II software runs nearly three times as fast on the IIGS by default.
The system is a radical departure otherwise, with a WDC 65C816 microprocessor, 256 KB—1 MB of random-access memory expandable to 8 MB, resolution and color similar to the Amiga and Atari ST, and a 32 channel Ensoniq wavetable synthesis chip. Bundled with a mouse, it is the first computer from Apple with a color graphical user interface and the Apple Desktop Bus interface for keyboards, mice, and other input devices.
The IIGS blurred the lines between the Apple II and Macintosh. After releasing the IIGS, Apple chose to focus on the Mac and no new Apple IIGS models were released. The standard RAM was doubled to 512 KB in 1988, then to 1 MB in 1989, and there were two firmware updates. Apple ceased IIGS production on December 4, 1992.
Hardware
The Apple IIGS made significant improvements over the Apple IIe and Apple IIc. It emulates its predecessors via a custom chip called the Mega II and uses the then-new WDC 65C816 16-bit microprocessor. The processor runs at, which is faster than the 8-bit processors used in the earlier Apple II models. The 24-bit memory addressing of the 65C816 allows the IIGS to use considerably more RAM. The original 65C816 processor in the IIGS was certified to run at up to. Faster versions of the 65C816 processor were readily available, with speeds of between 5 and 14 MHz, but Apple kept the machine at 2.8 MHz throughout its production run.Its graphical capabilities have higher resolution video modes and more color than 8-bit Apple II models. These include a 640×200-pixel mode with 2-bit color depth and a 320×200 mode with 4-bit color, both of which can select 4 or 16 colors at a time from a palette of 4,096 colors. By changing the palette per scan line, it is possible to display 3,200 colors at once.
The audio is generated by a Ensoniq 5503 digital synthesizer chip with 32 channels of sound. These channels can be paired to produce 15 voices in stereo. There is 64 KB of dedicated RAM for use by the 5503.
The IIGS supports both 5.25-inch and 3.5-inch floppy disks and has seven general-purpose expansion slots compatible with those on the Apple II, II+, and IIe. It also has a memory expansion slot for up to 8 MB of RAM. The IIGS has ports for external floppy disk drives, two serial ports for devices such as printers and modems, an Apple Desktop Bus port to connect the keyboard and mouse, and composite and RGB video ports.
A real-time clock is maintained by a built-in battery.
The IIGS also supports booting from an AppleShare server, via the AppleTalk protocol, over LocalTalk cabling. This was over a decade before NetBoot offered the same capability to computers running Mac OS 8.
Graphics
In addition to supporting all the text and bitmapped Apple II graphics modes of earlier models, the Apple IIGS's Video Graphics Chip introduced a new "Super-High Resolution" mode with a vastly wider color palette and no color bleeding and fringing. Super-High-Resolution supports 200 lines, in either 320 or 640 pixels horizontally. Both modes use a 12-bit palette for a total of 4,096 possible colors. There can be between 4 and 3,200 colors onscreen at once, with no more than 16 per line. A fill mode setting allows fast solid-fill graphics by automatically repeating a pixel's color to the right along the same scan line—until a different color pixel is reached.Each row of the display can independently select either 320 or 640 pixels, fill mode, and any of the 16 palettes. These settings provide many possibilities:
- 320×200 pixels with a single palette of 16 colors.
- 320×200 pixels with up to 16 palettes of 16 colors. The VGC holds 16 separate palettes of 16 colors in its own memory. Each of the 200 scan lines can be assigned any one of these palettes, allowing for up to 256 colors on the screen at once.
- 320×200 pixels with up to 200 palettes of 16 colors. The CPU assists the VGC in swapping palettes into and out of the video memory so that each scan line can have its own palette of 16 colors, allowing for up to 3,200 colors on the screen at once.
- 320×200 pixels with 15 colors per palette, plus a fill-mode color. Color 0 in the palette is replaced by the last non-zero color pixel displayed on the scan line.
- 640×200 pixels with 4 pure colors.
- 640×200 pixels with up to 16 palettes of 4 pure colors. The VGC holds 16 separate palettes of 4 pure colors in its own memory. Each of the 200 scan lines can be assigned any one of these palettes, allowing for up to 64 colors on the screen at once.
- 640x200 pixels with up to 200 palettes of 4 pure colors. The CPU assists the VGC in swapping palettes into and out of the video memory so that each scan line can have its own palette of 4 colors, allowing for up to 800 colors on the screen at once.
- 640×200 pixels with 16 dithered colors. Two palettes of four pure colors each are used in alternating columns. The hardware then dithers the colors of adjacent pixels to create 16 total colors on the screen.
Audio
A standard -inch headphone jack is on the back of the case, and standard stereo computer speakers can be attached there. This jack provides only monaural sound and a third-party adapter card is required for stereo; despite that, the Ensoniq and virtually all native software produces stereo audio. The Ensoniq can drive 16 speaker output channels, but the Molex expansion connector Apple provided only allows 8. There is 64 KB of dedicated memory on the IIGS motherboard, separate from system memory, for the Ensoniq chip to store its sampled wavetable instruments.
To exploit the IIGS's audio capabilities, during its introduction, Apple sold Bose Roommate amplified speakers for the computer.
Expansion
The expansion slots on the IIGS can be used to increase the computer's capabilities with contemporary and modern hardware, such as SCSI host adapters for external SCSI devices like hard drives and CD-ROM drives, or adapters for more recent internal 2.5-inch IDE hard drives. Available Apple II peripheral cards include accelerator cards, which replace the computer's original processor with a faster one.Development
said in January 1985 that Apple was investigating the 65816, and that an 8 MHz version would "beat the pants off a 68000 in most applications", but any product using it would have to be compatible with the Apple II. Rumors spread about his work on an "Apple IIx". The IIx was said to have a 16-bit CPU, one megabyte of RAM, and better graphics and sound. "IIx" was the code name for Apple's first internal project to develop a next-generation Apple II based on the 65816. The IIx project became bogged down when it attempted to include various coprocessors allowing it to emulate other computer systems. Early samples of the 65816 were also problematic. These problems led to the cancellation of the IIx project.A new project was later formed which led to the IIGS. It was known by various codenames during development: "Phoenix", "Rambo", "Gumby", and "Cortland".
Some design features from the unsuccessful Apple III lived on in the Apple IIGS, such as GS/OS borrowing elements from SOS, a unique keyboard feature for dual-speed arrow keys, and colorized ASCII text.
Release
Limited Edition ("Woz"-signed case)
As part of a commemorative celebration marking the 10th anniversary of the Apple II series' development, as well as Apple Computer itself celebrating the same anniversary, a special limited edition was introduced at product launch. The first 50,000 Apple IIGSs manufactured had a reproduced copy of Wozniak's signature at the front right corner of the case, with a dotted line and the phrase "Limited Edition" printed just below it. Owners of the Limited Edition, after mailing in their Apple registration card, were mailed back a certificate of authenticity signed by Wozniak and 12 key Apple engineers, as well as a personal letter from Wozniak himself. Because the difference between standard and Limited Edition machines was purely cosmetic, many owners of new were able to "convert" to the Limited Edition by merely swapping the case lid from an older machine.Upgrading an Apple IIe
Upon its release in September 1986, Apple announced it would be making a kit that would upgrade an Apple IIe to a IIGS available for purchase. This followed an Apple practice of making logic board upgrades available that dated from the earliest days of the Apple II until Steve Jobs' return to Apple in 1997. The IIe-to-IIGS upgrade replaced the IIe motherboard with a 16-bit IIGS motherboard. Users would take their Apple IIe machines into an authorized Apple dealership, where the IIe motherboard and lower baseboard of the case were swapped for an Apple IIGS motherboard with a new baseboard. New metal sticker ID badges replaced those on the front of the IIe, rebranding the machine. Retained were the upper half of the IIe case, the keyboard, speaker, and power supply. Original IIGS motherboards have electrical connections for the IIe power supply and keyboard present, although only about half of those produced have the physical plug connectors factory-presoldered in, which were mostly reserved for the upgrade kits.The upgrade cost US$500, plus the trade-in of the user's existing Apple IIe motherboard. It did not include a mouse, and the keyboard, although functional, lacked a numeric keypad and did not mimic all the features and functions of the Apple Desktop Bus keyboard. Some cards designed for the GS did not fit in the Apple IIe's slanted case. In the end, most users found that the upgrade did not save them much money once they purchased a 3.5-inch floppy drive, analog RGB monitor, and mouse.