- High-resolution graphics mode—6 colors, 280 horizontal by 192 vertical dots.
- Double-high resolution graphics mode—black and white, 560 horizontal by 192 vertical dots; 16 colors 150 horizontal by 192 vertical dots.
- Super-high-resolution graphics mode—4 colors, 650 horizontal by 200 vertical dots; 16 colors, 320 horizontal by 200 vertical dots.
The 40-column text mode and all four graphics modes can be displayed on either a TV or a monitor. The 80-column text mode requires a monochrome or analog RGB monitor.
The Apple IIGS generates 96 ASCII characters in uppercase and lowercase and also generates 32 graphics characters, called MouseText. Text is formed by a 5 by 7 dot matrix and can appear on the screen as normal, inverse, flashing or MouseText.
Color is output as an NTSC signal or an RGB signal.
The Apple IIGS uses a 65C816 microprocessor, operating at up to 2.8 megahertz. The chip has six 16-bit registers: the accumulator, two index registers, the direct register, the stack pointer, and the program counter. And it has three 8-bit registers: the data bank register, the program bank register, and the status register. The data bus is 8 bits wide, and the address bus is 24 bits wide, giving the microprocessor an address range of 16,777,216 bytes.
The Apple IIGS comes with 256K RAM and 128K ROM. The ROM contains the Apple IIGS's system monitor, Applesoft BASIC interpreter, the Control Panel Program, 80-column display firmware, and high-level software tools such as the Memory Manager.
The system monitor includes a machine-language disassembler, automatic input/output device assignment, keyboard and screen-editing features, and routines to examine and modify registers.
