Apple II GS

"A Colorful Apple Always Tastes Better"

Manufactured from 1986 until 1992, the Apple IIGS was the first truly multimedia Apple computer. Steve Wozniak was involved in the design and layout of the computer. Based on a 16-bit CPU, the IIGS offers significantly improved graphics and sound compared to earlier Apple II models, while being fully compatible with them (via the Mega II chip). The computer was sold for $999 or about $2,640 in today’s money.

• About 1 million units were ever sold, and the first 50,000 units had a reproduced copy of Wozniak's signature at the front right corner of the case ("Woz Edition")
• GS stands for "Graphics and Sound"

THE GS AT A GLANCE

• GS/OS operating system (early versions used the ProDOS 16)
• GUI mouse-driven interface
• 16-bit WDC 65C816 microprocessor running at 2.8 MHz
• Originally 256 KB of direct RAM (later models 1 MB), upgradable to 8 MB
• 128 KB of ROM (later models 256 KB)
• 12-bit color palette (4,096 colors)
• Wavetable synthesis chip from Ensoniq (impressive stereo sound)
• Supports 3.5/5.25-inch external floppy disk drives
• Highly expandable computer (7 expansion slots)
• Apple Desktop Bus for connecting mice, keyboards, and other devices
• Emulates its Apple II predecessors by using the custom Mega II chip
• Many applications and over 300 games for the IIGS

Operating System

The IIGS offers a mouse-driven graphical user interface (GUI) with windows and icons like the later macOS.

• Early versions used the ProDOS 16 operating system, later versions used the standard 16-bit GS/OS
• It is loading part from ROM and another part from disk
• It includes a finder application
• No multitasking, however, the “New Desk Accessories” can run parallel to standard desktop applications
• Later, a similar to the UNIX multitasking kernel was offered by third parties (GNO/ME)
• Apple claimed that the IIGS was 95% software-compatible with earlier Apple II models

Colors & Graphic Modes

The IIGS offers remarkable graphical capabilities with higher resolutions and more colors than any other Apple computer of that time.

• Supporting all video modes of earlier Apple II models
• A color palette of 4,096 colors
• Can display 256 colors on screen (using special modes you can have many more colors on screen)

The IIGS supports all video modes of older Apple II models, however, it introduced the new Super-High Resolution (SHR) video modes.

□ Super-High-Resolution (320 mode)

• 320x200 (16 colors / 4,096 color palette)
• 320x200 (256 colors / 4,096 color palette)
• 320x200 (3,200 colors / 4,096 color palette)

□ Super-High-Resolution (640 mode)

• 640x200 (4 colors / 4,096 color palette)
• 640x200 (16 colors / 4,096 color palette)
• 640x200 (64 colors / 4,096 color palette)
• 640x200 (800 colors / 4,096 color palette)

Sound Capabilities

The sound chip inside the IIGS is the impressive Ensoniq 5503 digital synthesizer chip which was used in several professional Ensoniq synthesizers.

• 8-bit audio resolution with 32 sound channels
• 64 KB of dedicated sound-chip RAM (DOC-RAM)
• Can produce 15 voices in stereo (allows a maximum of 32 voices)
• Can support 8 independent stereo speaker channels
• The creator of the Ensoniq 5503 Chip (DOC) was Bob Yannes, who also created the amazing SID synthesizer chip for the C64

I/O Ports

• Two serial ports (mini-DIN8) for connecting printers, modems, LocalTalk network, etc.
• Apple Desktop Bus port (mini-DIN4) for connecting a keyboard and a mouse
• RGB (DA-15) and composite video ports
• The headphone jack (1⁄8-inch) on the back of the case
• Joystick port (DE-9)
• Floppy disk drives (D-19)
• RTC (inside) by using a built-in battery

Expansions & Upgrades

• Up to 8 MB of RAM via the IIGS Memory Expansion slot (44-pin)
• 7 Apple II Bus slots expansion slots (50-pin), compatible with Apple II, II+, and IIe
• External floppy disk drive
• Apple SCSI expansion card (external SCSI devices such as CD-ROM drives and external hard disks)
• 2.5-inch IDE hard disk drive adapters
• CompactFlash cards
• Accelerator cards (TransWarp GS, Zip GSX, etc.)
• PC Transporter by Applied Engineering (IBM-PC/XT combability)

Hardware Revisions

• ROM-0, the initial IIGS version, was released in September 1986
• ROM-01, with updated ROM routines, was released in September 1987
• ROM-3, with a revised motherboard, 1 MB of built-in RAM, and better audio quality, was released in August 1989
• ROM-4, which was designed but never released

Sources:

• Wikipedia
• Apple IIgs Owner's Guide (PDF)
• https://www.apple2history.org/history/ah10/