40×48 (16 colors) High resolution: 280×192 (6 colors) Double low resolution: 80×48 (16 colors) Double high resolution: 560×192 (16 colors) Native video Super-high resolution (320 mode) 320×200 (16 colors, selectable from 4,096 color palette) 320×200 (256 colors, selectable from 4,096 color palette) 320×200 (3,200 colors, selectable from 4,096 color palette) Super-high resolution (640 mode) 640×200 (4 colors, selectable from 4,096 color palette) 640×200 (16 dithered colors, selectable from 4,096 color palette) 640×200 (64 colors, selectable from 4,096 color palette) 640×200 (800 colors, selectable from 4,096 color palette) Fill mode 320×200, sections of screens filled in on-the-fly for up to 60 frame/s full-screen animation Mixed mode 320/640×200, horizontal resolution selectable on a line-by-line basis Audio Ensoniq 5503 digital oscillator chip 8-bit audio resolution 64 KB of dedicated sound RAM 32 oscillator channels (15 voices when paired) Support for eight independent stereo speaker channels Expansion Seven Apple II Bus slots (50-pin card-edge) IIGS Memory Expansion slot (44-pin card-edge) Internal connectors Game I/O socket (16-pin DIP) Ensoniq I/O expansion connector (7-pin molex) Specialized chip controllers IWM (Integrated Woz Machine) for floppy drives VGC (video graphics controller) for video Mega II (Apple IIe computer on chip) Ensoniq 5503 DOC (sample-based synthesis) Zilog Z8530 SCC (serial port controller) Apple Desktop Bus microcontroller FPI (Fast Processor Interface) or CYA (Control Your Apple) External connectors NTSC composite video output (RCA connector) Joystick (DE-9) Audio-out (-inch mono phono jack) Printer-serial 1 (mini-DIN8) Modem-serial 2 (mini-DIN8) Floppy drive (D-19) Analog RGB video (DA-15) Apple Desktop Bus (mini-DIN4) Revision history While in production between September 1986 and December 1992, the Apple IIGS remained relatively unchanged from its inception. During those years, however, Apple did produce some maintenance updates to the system which mainly comprised two new ROM-based updates and a revamped motherboard. It is rumored that several prototypes that greatly enhanced the machine's features and capabilities were designed and even built, though only one has ever been publicly exposed (i.e. the "Mark Twain"). Outlined below are only those revisions and updates officially released by Apple. Original firmware release ("ROM version 00") During the entire first year of the machine's production, an early, almost beta-like, firmware version shipped with the machine and was notably bug-ridden. Some limitation of this include the fact that the built-in RAM Disk can't be set larger than 4 MB (even if more RAM is present) and the firmware contains the very early System 1.x toolsets. It