Re: Apple ///

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

In article <mnementhCHux9A.I04@netcom.com> mnementh@netcom.com (David R. Villegas) writes:
> In a nutshell, what's an Apple /// and is it compatible in any way with the
> other Apples?

I'm probably not the best person to answer this - there are others on
the net with much more experience of the Apple ///.

The Apple /// has many similarities to the Apple // family.  It uses a
6502 microprocessor, has slots which are compatible with the Apple //
(to some extent), uses the same 5.25" disk format (its file system is
compatible with ProDOS) and has a special Apple ][+ emulation mode
(48k only).

The similarities end there.  The /// is a much more powerful computer
than the ][+ or //e.  In its native mode, it is unable to run Apple //
software.

Here are a few of its extra features:

- The processor runs at 2 MHz (twice the speed of the Apple II).
- Full ASCII keyboard (like the //e), with dual-speed arrow keys.
- Comes with 128k or 256k of RAM and can be expanded up to 512k.
- There are hardware extensions to the microprocessor which allows it
  to directly address all of the RAM.  (The ][+ and //e have to use
  bank-switching techniques to access more than 64k of RAM).
- The entire machine is "soft".  The only ROM it contains allows it to
  boot from the internal 5.25" disk.  Everything is loaded from the
  system disk, including the text mode character set (which can be
  fully reprogrammed), BASIC (if you want to use it) and device
  drivers for the console, sound, disk drive, serial port, devices in
  the slots, and anything else built into the computer.
- It has a much more powerful version of BASIC (called Apple ///
  Business Basic) and a better Pascal compiler than Apple ][ Pascal.
- The operating system (SOS - Sophisticated Operating System) is very
  configurable, with loadable device drivers for block and character
  devices.

I'm sure there are a lot of things I've forgotten.  In particular, I'm
not sure what it has in the way of built-in I/O (serial, parallel, etc.)

ProDOS is basically a very cut-down version of SOS (supporting block
devices only).

GS/OS (the IIgs operating system) borrowed a lot of features from SOS.

The IIgs is the only Apple II which I'd regard as being more powerful
than the Apple ///.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz                                                
Snail mail: P.O. Box 27-103, Wellington, New Zealand