The Apple IIgs was introduced in 1989, with the gs suffix indicating “graphics and sound”.
It’s not necessarily the most poweful computer of its time, but it’s certainly the final and most advanced of the Apple II models. Like the Apple II systems before it, it supports the 6502 instruction set, but also supports an extended 16-bit set of instructions.
Hardware and emulation
Operating Systems and Software
The Apple IIgs can boot from a variety of sources, but notably lacks a cassette port as typical on older II systems:
- Smartport accessories
- Serial port
- Expansion cards
The IIgs sold with a 3.5” drive but also supports 5.25” disk drives. Although earlier models relied heavily on 5.25” disks, with the IIgs, I found that I was fully satisified with a single 3.5” drive and a FloppyEMU which can emulate multiple devices including 5.25” disks.
The FloppyEMU emulates both floppies and smartport devices. As a smartport device, you can mount and boot from 32MB ProDOS volumes. There’s some really excellent images prepared in this size to run GSOS and ProDOS.
There’s a number of development languages for the IIgs, but serious development trends toward writing assembly. There’s also a fair number of assemblers, including one built-in to the system’s ROM.
Personally, I settled on Merlin which comes in 8-bit and 16-bit flavors. It also runs under Linux, including ARM64, making it convenient for integrating into a modern CI/CD pipeline.
I also prefer to develop and test in an emulator.