What is Gus 1.0d4?

“Gus” is the name Apple Engineers Dave Lyons, Jim Murphy, and Steve Stephenson gave to their Apple IIGS's when they first bought them in 1986 and 1987. So, we thought it was a fitting name for an Apple IIGS emulator. 

Gus is a Macintosh application which emulates the 65816 microprocessor, displays, sound generation and other hardware found in an Apple IIGS. Gus has also been specially tuned to provide accelerated performance when run on any Power Macintosh ...

What works?

We have written hardware emulations for all 13 available video modes, the Apple Il memory system, the Apple Desktop Bus (ADB) KeyMicro, single-bit "Classic" Apple II sound, the Joystick, the clock, and the IWM disk hardware.

We also implement some “patches” to the image of the Apple IIGS ROM 03 image which allows us to do things like boot from an Apple “Disk Copy” disk image. There is also a simple architecture to allow us to accelerate portions of the GS ROM should we find this necessary; we have only needed to accelerate some absolutely key areas, such as IIGS Toolbox dispatching. 

As for video modes, we provide: 40 column and 80 column text with all the appropriate background and text colors, Hi-Res in both B&W or Color, Double Hi-Res in both B&W or Color, Lo-Res, Double Lo-Res, Super Hi-Res 320, Super Hi-Res 640, all the "mixed" graphics and text modes, and even Super Hi-Res fill-mode. The color graphics modes for Hi-Res and Double Hi-Res are rendered using color-bleeding and match the output provided by the Apple Ile card for the Macintosh LC. Most of the graphics modes perform extremely fast updates; that is, most graphics on Gus are substantially faster than the Apple IIe card. 

Gus boots from Disk Copy “disk images” or Apple II ShrinkIt-compressed “disk images”. Just put the disk image file in the same folder as Gus, launch Gus and you're booting. 

Gus runs in a standard Macintosh window and is System 7-savvy as you would expect of any Macintosh application. The Gus window works across multiple monitors and in any screen depth, although you will get the best performance in 256-color mode with the window entirely on a 256-color screen. 

Apple IIGS Memory Size 

The Apple IIGS memory size is determined by the size of the Gus application size. "Get Info" on the Gus application icon and crank it up. You can have up to 14 Megs of RAM in the GS.

Kerwood, D.R. (1996). Gus Fact Sheet. KansasFest '96. (pgs. 1-2).

Download Gus 1.0d4 for Mac

Architecture

68K + PPC (FAT)

System Requirements

From Mac OS 7.5 up to Mac OS 9.2

Compatibility notes

Emulating this? It could probably run under: SheepShaver