Okay, as promised the Apple III presentation I gave at KansasFest is now available at the KansasFest website (it’s in the downloads area, along with a link to my pictures and a bunch of other goodies).  I should probably clarify a few things, the most important being that I am a horrible public speaker.  Even the thought of getting up in front of any amount of people to talk to them is enough to keep me up nights.  My brain has a tendency to freeze up and even simple answers to audience questions leave me a stammering mess.  In fact, there’s a video of me “giving my presentation” (by which, I mean babbling incoherently for half an hour) on the web now as well, but I’m not going to link to that.  You’ll have to find it yourself.

Anyway, as a result of my deer-caught-in-headlights panic, I managed to leave out large portions of information I had intended to give.  Since this blog gives me my own small soapbox, I’ll take this opportunity to fill in what I  missed or just got plain wrong.

5V vs 12V

I remember being asked why Apple didn’t just go with a lower-powered 5V system from the beginning, instead of introducing the 12V Apple III and then later replacing it with the 5V revised version.  I think the answer that came fumbling out of my mouth might have been close to correct, but I can’t be sure so I’ll address it here.  The simple answer is the price of RAM at the time.  5V RAM chips were still very pricey when the Apple III was under development and it was deemed too expensive, so the engineering team went with the older 12V RAM instead.  By the time Apple got around to fixing the numerous flaws in the original III, 5V RAM had become cheap enough to be economically viable in the III.  So, as part of the redesign, a 5V memory system was introduced.  In fact, 5V and 12V boards are interchangeable in the various Apple III iterations – with a few simple modifications, a 5V memory board could easily work in a 12V system.  It’s apparently trivial to switch the entire Apple III from 12V to 5V, and in fact the steps are outlined in the Apple III Technical Procedures document.  During the time that Apple was replacing or fixing bad III’s like crazy, dealers who serviced any 12V Apple III were, as part of the procedure, required to convert the machine to 5V.

6502A vs B

Someone asked me about the difference between Synertek’s 6502A processor, which shipped in early versions of the Apple III, and the 6502B, found in the “revised” III and III+.  I think I mumbled some nonsense about opcodes.  The only difference between the A and the B is speed.  The A is rated at 2 MHz, though on the III, it runs closer to 1.8 MHz; the B was SynerTek’s next version of the chip, and could run at 3 MHz in systems designed to handle the additional speed.  It’s really academic in the case of the Apple III however, as both the A and the B were clocked to 2 MHz.

Edit: It’s probably also worth mentioning that the same is true for the original 6502 that appeared in early Apple II models:  it’s functionally identical to the 6502A/B – just operating at 1 MHz.

Brief history

I’d meant to cover this quickly at the start of the presentation, but forgot not only to mention it, but to even put it in the PowerPoint file.

By 1978, Apple was worried that they had a year, maybe two before sales of the Apple II line fell off and they needed a replacement.  Macintosh and its progenitor Lisa were still years away and the executive board felt they needed to move ahead with something sooner.  A group was put together to come up with preliminary designs for a new machine and Apple even brought in 6502 creator Chuck Peddle to help out.  The group, consisting mainly of marketing types, wanted a machine that was more powerful than the II to give them a foot in the business marketplace door, but still maintained contact with the II and II+ in the form of software emulation.  Apple had intended first Peddle (who returned to Commodore a short time later after he and Apple couldn’t come to satisfactory terms on his employment) and then Woz himself to head up the engineering team that would design the electronics and build this new computer.

When it became apparent that Woz wasn’t interested in doing more than some basic design work, Apple turned to Dr. Wendell Sander.  Dan Kottke was also brought in to be Sander’s technician – as Sander handed diagrams and schematics off, Kottke would come in and build and troubleshoot the hardware, spending long nights wire-wrapping boards and fixing previously unseen flaws.  Rumors began to fly of an new personal computer being designed by the Evil Empire, IBM.  Apple panicked (much in the way I did) and pushed the engineering team to hurry up the release.  As often happens when a committee gets together, individual members had a hard time agreeing with each other on what the final product should look like and the engineering team ended up with a constantly changing sheet of specifications around which to design.  The engineers did the best they could but warned that there were problems and that thorough testing was needed before the Apple III could be released.  Their warnings were ignored and the QA process – which could have saved Apple millions – was cut short.  The resulting product was a disaster.

And it goes from there into my presentation.

There’s probably more that should be addressed, but I haven’t been able to bring myself to watch the presentation video.  Maybe someday…