Re: IIgs

[dempson@actrix.gen.nz (David Empson)]

Note - I've directed followups to comp.sys.apple2, as this discussion
isn't appropriate in the communications sub-group.

In article <ABROADST.94May5145038@occs.cs.oberlin.edu>,
Andrew Broadstone <abroadst@cs.oberlin.edu> wrote:
> 
> I'm unfamiliar with the IIgs and was wondering in anyone could give me
> an idea of how it differs from my IIc. Sun Remarketing is selling
> IIgses for less than IIe's. Does that mean a IIe offers more
> capability?

Definitely not!  You can think of a IIgs as a combined IIe and IIc,
with a more powerful processor, faster execution, and a lot of extra
capabilities.

First, let's compare a IIe to a IIc.

The IIc is basically an enhanced Apple IIe with 128k of RAM and
several built-in I/O ports instead of slots.

The IIc has the equivalent of two Super Serial Cards, an extended
80-column card, a mouse interface, a 5.25" disk controller, and (if you
have one of the later ROM revisions) a UniDisk 3.5 controller
(SmartPort) and memory expansion card.  The IIc also has a built-in
disk drive, whereas the IIe will normally have an external drive (or
drives).

If you were to add all of this to a IIe, you would need to put cards
in all the slots.  The IIc is an all-in-one machine with a standard
set of options, while the IIe is flexible - you can put whatever cards
you like into the slots.


The IIgs has the best of both worlds: it has slots AND built-in I/O
ports.  The built-in "Control Panel" program allows the user to select
whether a particular slot is used for its built-in port function, or
as an external slot.

The built-in ports are: two serial ports, 80-column firmware, mouse,
SmartPort (supporting the Apple 3.5 Drive, UniDisk 3.5 Drive, and a
built-in RAM disk and optional ROM disk), 5.25" disk controller, and
AppleTalk network interface (which replaces one of the serial ports).

The IIgs supports an analogue RGB monitor, which produces a much better
colour picture than composite colour monitors.  There is a composite
output as well, which will work with existing monitors.

It also uses the "Apple Desktop Bus" for connecting the keyboard,
mouse and some other peripherals.  This is the same interface used on
all Macintoshes since the Mac SE.

There is also a built-in clock and battery-backed RAM, which is used
to store various settings for the computer.  The battery-backed RAM is
accessed through the Control Panel program.  It allows you to select
the following options:

- Screen border colour
- Text display foreground and background colour
- Whether you have a monochrome or colour composite monitor
- Whether to default to 40 or 80 column display
- Sound volume and pitch of the standard "beep"
- System speed: fast (about 2.6 MHz) or normal (1 MHz).  The IIe and IIc
  run at 1 MHz.  You can get accelerator cards (the ZIP GS or
  TransWarp GS) which allow the computer to run at much higher speeds.
- Set the clock, and choose the display format for dates and times
- Display language (English, French, etc.) and keyboard layout
- Turn Keyboard buffering on or off (a 15 chracter type-ahead buffer)
- Set the keyboard repeat speed and delay
- Set the cursor blink rate
- Enable various advanced keyboard options
- Select internal port or external slot for each of slots 1 to 7
- Select the startup slot (1 to 7, Scan (as in the IIe), RAM disk, ROM disk
  or AppleTalk
- Configure the serial ports
- Set the size of the RAM disk
- Set the responsiveness of the mouse (movement and double click)

Further setting are available through a desktop version of the Control
Panel, which is included with the IIgs system software.


The name of the machine comes from "Graphics and Sound".  The IIgs
supports all IIe and IIc video modes, plus a new "Super Hi-Res
Graphics" mode.  In this mode, the IIgs can display up to 16 colours
from a palette of 4096, with a resolution of 320 or 640 pixels
horizontally, and 200 vertically.  Smart software can extend the
number of visible colours to 256 or 3200 by using special techniques,
but there are limitations on where the colours can be used.

(By comparison, the standard hi-res graphics mode is 140 by 192 pixels
with 6 fixed colours, or 280 by 192 pixels with a monochrome monitor;
the double hi-res graphics mode is 140 by 192 with 16 fixed colours, or
280 by 192 with a monochrome monitor.)

The IIgs has a dedicated sound chip called the "Ensoniq", which can
play digitized waveforms with up to 15 voices in normal circumstances.
The IIgs has mono sound output built into the computer, but you can
add a card to produce stereo or multi-channel output.


The IIgs's processor is a 65816, which can emulate a 65C02, and can
also run in 16-bit mode.  It can address up to 16 megabytes of memory
(compared to 64 kilobytes for a 65C02, as used in the IIe and IIc).
The IIgs supports up to 8 megabytes of RAM and a megabyte of ROM.

The IIgs will run nearly all existing IIe and IIc software.  As such,
it basically runs as a fast IIe, with the processor emulating a 65C02.
It can run ProDOS, DOS 3.3 and Apple Pascal.  If you add a Z-80 card,
you can also run CP/M.

The IIgs really shines when you run native software.  This usually
requires the IIgs's native operating system "GS/OS".  Native IIgs
programs have access to far more memory than IIe or IIc programs, and
usually run in a desktop environment, which is supported by the
operating system and toolbox in ROM.


There are two major versions of the IIgs.  The original IIgs comes
with 256k of RAM and 128k of ROM.  This is usually called the "ROM 01"
IIgs, because the most recent version of the ROM for this machine is
version 1.  (The original ROM is called "ROM 0", and is not supported
by current system software.  Upgrading to ROM 01 is free.)

The later version of the IIgs comes with 1.125 MB of RAM and 256k of
ROM. This is usually called a "ROM 3" IIgs, but its official name is
the "One megabyte Apple IIgs".  There is no way to "upgrade" a ROM 1 to a
ROM 3, except by swapping motherboards.

The ROM version is displayed at the bottom of the screen when the
computer starts up (except for the original ROM 0).

Both machines have a special memory expansion slot which can be used
to add up to 4 megabytes to the machine (for a total of 4.25 or 5.125,
depending on which version of the IIgs you have).  There are some cards
which let you go up to 8 megabytes, and also cards which provide a ROM
disk capability.


Physically, the computer looks vaguely like a square IIe with a
detached keyboard.  You could compare it to a Macintosh IIcx or
similar machine, except it is smaller.

> Is the gs an attempt to make the Apple II look like a macintosh?

Yes.  Native IIgs software uses a desktop environment which is very
similar to the Macintosh (through to Macintosh System 6, anyway).  The
IIgs also has a ROM-based (and disk-based) toolbox for implementing
the desktop environment, which is quite similar to the Macintosh toolbox.


I hope this answers some of your questions.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand