The Apple IIGS
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The Apple IIGS was Apple's `other option' compared to the Mac, which was a full
break in compatibility to the 8-bit Apple II. It's what would have happened if
Apple paid more attention to their user base...give them a 16-bit computer that
was backward compatible with the 8-bit world just like Windows 3.1 could run
DOS software. Give them a few years before you hit them with Windows 95 and
Had Apple not thrown its future completely with the Mac, it would be in better
shape today. But back in those days, Apple was split. You had Wozniak, who
thought like this. Then you had Jobs who believed that IBM and clones were
evil plus Jobs didn't care much for Woz hogging up the spotlight. Then Woz
left Apple, leaving Jobs in control. The rest is history.
The IIGS was supposed to be the bridge for A2 users to go into the future. But
Woz left Apple after designing the basic architecture of the computer and the
other Steve (Steve Jobs) did not want Woz to leave the dominant mark at Apple,
so he withdrew support from the Apple II program (including the IIGS) and
pointed Apple in the direction of the Mac, which was not II compatible.
Apple ][GS specs
The Apple IIGS was Apple Computer Inc.'s only 16-bit computer (compared to the
other Apple II which were 8-bit and the Mac models which are 32-bit). It
featured a more advanced processor that could directly address up to 16MB of
memory without bank switching. It had a color palette of 4096 colors and had
graphics modes that could put 3200 colors from that palette onto the screen at
any one time. There was a hardware fill mode implemented by a custom graphics
chip called the VGC (Video Graphics Chip) for high speed graphic animation.
The video itself was higher resolution than the earlier Apple II units. Up to
640 pixels horizontal. The slots were given a video signal that allowed for
future video expansion. I've added an SVGA card to my IIGS, for example, for
modes up to 1024x768 pixels and colors up to 24-bit.
The most impressive aspect of the IIGS was the sound chip. The Ensoniq 5503
DOC wavetable synthesis core used in the IIGS audio system can do everything
from speech synthesis to playing MIDI and MOD files to playing converted MP3
Here are some pictures of the IIGS up and running with great software:
Less flashy but significant, the Apple IIGS is programmed like a Mac. It has
a toolbox for constructing the Mac GUI. Now Mac programs can't just be run on
the IIGS because the CPU is different, but the two are similar enough that if
you can program a Mac, you can program a IIGS and compilers such as for C or
Pascal work similarly in both (with respect to use of the toolbox tools).
The IIGS can take Mac ADB keyboard and mice. If the IIGS is set up to use
TrueType fonts, it can take Mac fonts right off Mac disks or CD-ROMs. Many
Mac resources can also be used.
Emulation of the Apple][
There is a VLSI chip on the IIGS motherboard that is literally an entire Apple
IIe minus the RAM, ROM, and CPU shrunk onto a single chip. The chip is called
the Mega II. It is the hardware IIe emulator in the IIGS. The IIGS' own CPU,
the 65C816 can kick into an emulation mode where it mimics a 65C02 (CMOS 6502)
perfectly. The CPU combined with the Mega II is what allows the IIGS to run
older 8-bit Apple II software under emulation mode.