Apple "stealth" IIGS
This is the oldest of my computers, at least in terms of how long I've had
it. My parents bought it new in the summer of 1985, right as I was starting
"But Scott, wasn't the IIGS introduced in the fall of 1986? How did you get
one back then?"
I didn't...not exactly, anyway. :-) It started life as a IIe with 128K RAM,
two 5.25" floppy drives, a Monitor II green-screen, and an Imagewriter
connected through a Super Serial Card. Over the past 16 years, it's been
upgraded a bit at a time. The most significant upgrade was in 1993, when it
morphed into a ROM 01 IIGS with one of the upgrade kits sold by
I should really get some pics of this machine up, as it's the closest to a
"hot rod" that I have. It's seen extensive hardware modifications to get it
to where it is today:
Sequential Systems RAM-GS memory card with 4MB, modified to fit in a
Apple High-Speed SCSI Card (also have a rev. C RamFAST, but I couldn't
get the CD-ROM drive working with it).
ZipGS accelerator...originally 8 MHz with 16K cache, now
with 64K cache (had reliability issues running it at 12.5 MHz).
stock IIe power supply replaced with the innards of a 250W PS/2 (AT)
4.3GB Seagate Barracuda SCSI hard drive, in an external case (not shown) connected
through an 80-to-50-pin adapter.
4x SCSI CD-ROM drive (in the Sun case under the floppy drives)...and you can boot
NEC MultiSync 3D VGA monitor, one of the few that will sync down to
the IIGS's 15.75-kHz (same as NTSC) horizontal sync rate.
In addition to the DuoDisk, the system now has an Apple 3.5 Drive as well
since most GS software shipped on 3.5" floppies. A SupraFAXmodem
V.32bis that was a "hand-me-down" from the BBS I used to run is around here
somewhere, but I almost never need to use a modem anymore as the Internet
has all but wiped out the dial-up BBS. It's connected to the home network
through a Cayman GatorBox CS, a LocalTalk-to-Ethernet bridge. It'll talk
to a Linux box running Netatalk, or some of my older Macs (though not the
Mac mini...Mac OS X dropped support for the flavor of AFP spoken by the IIGS
at some point).
The out-of-the box hardware configuration for a ROM 01 IIGS is something
2.8-MHz 65C816 16-bit microprocessor, 100% backward-compatible with
256K RAM, expandable to 8MB.
Seven standard Apple II expansion slots, plus a dedicated memory-
Integrated graphics that support all modes supported by the IIe,
plus Super Hi-Res. This mode allows 200 lines of either 320 or 640
pixels each. Sixteen palettes are available; any scanline can use
any palette and can display either 320 or 640 pixels. 640-pixel
lines can use four colors from the palette, while 320-pixel lines can
use all sixteen palette colors (palette colors are selected from
4096 possible colors--four bits each of red, green, and blue).
Unlike other Apple II modes, which use a weird addressing scheme
selected to use one less chip in the original Apple II, Super Hi-Res
uses linear addressing like any other framebuffer. Output is to
both composite video (like other Apple IIs) and analog RGB at NTSC
scan frequencies (like the Amiga).
Integrated Ensoniq 5503 wavetable synthesizer, with its own 64K of
sample RAM...a feature that was way ahead of its time, considering
that most PCs didn't offer wavetable synthesis as a standard feature
until the mid-90s. This is a 32-voice, 8-channel synthesizer. As
used in the IIGS, two voices are reserved for system use and the
remaining 30 are typically used in pairs to yield 15 usable voices.
Also, all channels are mixed to produce mono output to the built-in
speaker or the headphone jack. "Soundcards" for the IIGS are little
more than demultiplexers and preamps (and sometimes power
amplifiers) that prepare line-level or microphone input for the
Ensoniq chip, demultiplex the audio signal into two channels for
stereo sound, and produce line-level and/or amplified output to
drive powered and/or unpowered speakers.
Two Zilog 8530 serial ports,
just like the Macintosh. In addition
to offering (mostly) RS-232-compatible serial communications for
printers and modems, LocalTalk networking was also possible.
One Apple Desktop Bus (ADB) port for keyboards and mice, which takes
most of the same keyboards and mice that a Mac can use. There are
also headers on the motherboard for the IIe keyboard and (optional)
numeric keypad, which I use instead of an ADB keyboard.
Integrated SmartPort floppy controller, based on the Integrated
Woz Machine (IWM) controller chip--a single-chip implementation of
Steve Wozniak's Disk II floppy controller.
Integrated real-time clock with some extra memory for system
settings (serial-port speeds, text colors, etc.).
Integrated DB-9 and DIP-16 joystick ports.
Some more pix:
Tons of Internet resources remain available for the Apple II. Here are some
of the more interesting links I've collected over the years:
Apple II History, everything you could want to know about the II
and the people behind it.
Marinetti, a TCP/IP stack for the IIGS that supports SL/IP and
PPP connections over the serial ports.
SHH Systeme, manufacturer of IDE controllers and Ethernet
adapters for the II.
ReactiveMicro sells new hardware and parts for vintage hardware.
Original content copyright © 1997-2013
Scott Alfter; all rights reserved.
Archived materials are the property of their respective owners.