Re: WANTED: Apple III info

[spector@vax2.concordia.ca (Mitchell Spector)]

In article dempson@atlantis.actrix.gen.nz (David Empson) writes...
> 
>Ah.  I think you got the order a little backwards.  The Apple III was
>released in 1980, and was no longer made after 1985 (or thereabouts).

	The Apple III was discontinued at the same time the Apple IIc
was introduced -- April 1984. 

>Yep.  The original Apple III was plagued with technical problems,
>which didn't do much for the reputation of the machine.  It was
>withdrawn and reintroduced in 1981 (was this the Apple III+, or did
>that come later?) with the problems fixed.

	The original introduction of the Apple III was in May 1980.
It was in December 1981 (just a few weeks before 1982) that Apple
reintroduced a "fixed" version of the Apple III. One of the fixes
involved revamping the motherboard so fewer chips were present, also
I think they placed DRAMs on a separate daugtherboard rather than
directly to motherboard itself (heat build up caused chips to literally 
jump from their sockets!). Other problems included failure of keyboards,
internal floppy drives, etc.

	The Apple III+ was a separate machine released two years later,
back during December 1983. It had a few minor enhancements, but I believe
it was mainly released to offset the bad feelings people had about the 
problems with the original III. One last ditch effort to see if they could 
save the machine (funny how they killed it only four months later, though 
they now seem comfortable doing this with models of the Macintosh family.. ;-)

>There is no ROM to speak of: 4k, containing initialization, bootstrap
>and diagnostics.  There is no equivalent to the Apple II monitor in
>the ROM, and no language built into the computer.  Everything is
>loaded from disk.  The only bootable device is the internal 5.25"
>drive (though that could be a pre-boot disk for booting properly off a
>different device).

	Are you sure? At cold-boot, without any disks loaded, I can
press CTRL-SA-RESET and get something simular to Monitor on screen.
A small arrow cursor; pressing Return or typing various addresses give
back Monitor-like output. It displays a "->" rather than "*" prompt.

>- Up to three additional 5.25" drives may be daisy-chained from the
>back of the computer.  The hardware of the Disk III drive is similar
>to the Disk II, but the connector is larger (to allow for
>daisy-chaining and some other features).

	Ahh, so that's what the external 5.25 is called. :) I should
have guessed the "Disk III" yet there's no label or engraving to be 
found on the Disk ]I[ drive I have.

>- Full ASCII keyboard, with Open-Apple and Solid-Apple keys.  The
>arrow keys have two pressure levels - push them lightly to repeat
>slowly, push them hard to move faster.

	As the first Apple manufactured with lowercase built-in, 
it's interesting to note Apple called the Caps-Lock key "Alpha-Lock"
(don't think I've seen this term used before, expect perhaps on old
dumb terminals and such). There was also no "Delete" key, although
the "| \" key was in it's place and of the same size. Some software
will let this key emulate Delete, such as "Three Easy Pieces". The 
Apple III Plus later added a "Caps-Lock" and "Delete" key, in fact,
the keyboard layout (minus numeric keypad) is virtually identical to
the Apple IIe produced between 1983 and late 1986.

>- Text screen supports 40x24 and 80x24 in black and white, or 40x24
>with 16 foreground and background colours.  The character set is
>software programmable (there isn't even a default set in ROM - it is
>always loaded from disk).

	Although I've heard the same about there being no character set
in ROM, there still seems to be something there. When you cold-boot an
Apple III, there's the built-in font for the Monitor I mentioned above,
as well as when the "? Retry" message appears after the disk drive gives
up scanning for a boot disk. If the keyboard lamp is burned out, a 
diagnostic routine runs in a endless loop, of which also uses a built-in
text font.

	Also worth mentioning, the 40x24 text mode with 16 foreground
and background colors is less limited than the colored text mode of the
Apple IIgs. You can mix colors on the same line, more or less like that
of IBM colored ANSI text (or that of the C=64 or 8-bit Atari computers).

>- Digital RGB and composite video outputs.

	Oddly enough, an AppleColor RGB (analog) monitor from a IIgs
system works directly from this port. Before anyone tries this though,
be warned it *might* damage your monitor! The screen would flicker 
between normal and a kind of pink tone, although I'm not certain if
this happen before or after I plugged it into the Apple III. [Hmmm,
my current RGB has a kind of permanent yellow-tint overlayed on
the display, though it's never been near the III...I guess these
screens may have been exposed to a strong magnetic field source]

>- Sound output is via an internal speaker or a connector on the back
>(similar to the IIc or IIgs).  Sound generation is via a 6-bit digital
>to analog converter (64 level digitized sound generation), a one-bit
>square wave generator (similar to the Apple II method), or a fixed
>frequency beep generator.

	The Apple III Diagnostic disk actually has a digitized human 
speech routine report the status of the machine using this DAC. If I 
remember correctly it says, "I'm okay...system status normal!". :)
There's no carrier noise, though it sounds like an 8-bit sound sample
played at 11 KHz or so (ie, just a tad bit fuzzy).

>- Four 50-pin slots, that are mostly compatible with the Apple II
>(some extra functions are available).  The Apple III doesn't use boot
>or driver ROMs like the Apple II - all device drivers for I/O cards
>are loaded from the system disk.

	Certain Apple II cards will function within these slots. 
Examples are the Grappler+ parallel printer interface, the Liron
UniDisk 3.5 card (with the correct SOS drivers). The later would
seem logical, as I have a UniDisk 3.5 driver for SOS and I very much
doubt Apple produced a UniDisk card specifically for the III in
1985 or later.

>The Apple III also has a special Apple II emulation mode, implemented
>in hardware with some software support.  In this mode, the Apple III
>emulates a 48k Apple ][ or ][+.  You cannot add a language card, so
>this is a very limited emulation.

	There is also hardware implemented to _prevent_ programmers from
borrowing more memory, higher density graphics, better sound or even
80x24 text from the III to use under Apple ][ emulation. Yes, Apple
disliked the presence of the Apple II as far back as 15 years ago...

>After booting the emulator disk (which loads the ROM images and sets
>up emulation mode), you can boot any Apple II DOS 3.3 disk that only
>requires 48k.  You can also access a configuration menu, which sets up
>options such as the ROM language (Integer or Applesoft BASIC) and
>serial port parameters.

	You can set the serial port to 19.2k under Apple II emulation,
or so the emulator software claims.

>There is a hardware product (whose name I've forgotten again) which
>allows Apple IIe software to be used on an Apple III.  It emulates at
>least a 64k IIe (I would expect it to emulate a 128k machine, but I
>don't know for sure).

	I believe it was the "Titan" card and it supported a 128k
configuration of RAM. Unfortunately the card only emulated the
original unehanced version of the IIe, though the manual claimed
you could replace the 6502 processor with a 65C02. 

>I think one of the issues of Steve Weyrich's Apple II history covers
>the Apple III.

	It does, but just scratches the surface really. I've found 
acquiring an Apple III and taking it apart was a good way to learn 
more about the machine in more depth (much the same way I've done 
with my Apple ][, ][+, //e's, former //c, and IIGSes.. :) 

>David Empson
>dempson@actrix.gen.nz
>Snail mail: P.O. Box 27-103, Wellington, New Zealand

Mitchell Spector
m_spect@pavo.concordia.ca / spector@vax2.concordia.ca