Archive for the ‘Apple 1’ Category

A CHM Youtube Video Worth Watching

Sunday, May 21st, 2017

The CHM’s youtube channel has this video, which caught my attention.

I’ve always been an advocate for the behind the scenes “little guy” that do 90% of the work that really make new products possible. My mom taught me, when I was little, that “words are cheap”. The same can be said for the new ideas that lead to breakthroughs in technology. There is always a foundation for these new ideas and they usually aren’t giant leaps, by themselves, but almost always, incremental steps in understanding.

In my mind, the hard part, isn’t coming up with the idea, but implementing it. In fact, many products are described decades before they can be implemented.

The stories on Andy Hertzfeld’s website, demonstrate the hard work that goes into implementation, as well as anything that I’ve ever seen. The thing to understand is that the effort that went into making Macintosh, isn’t unique, but rather the norm for almost all of the gadgets that we take for granted, these days. How do I know this, you may ask? Well, I’ve been involved in new product development for something like 38 years. Some of the products that I have worked on have been failures, but many of them, successful. In either case, it’s always a struggle for those involved. A rewarding struggle when it goes right, but still a struggle.

It seems Thomas Haigh understands this. I’ve ordered his book on Eniac and will write a review after I read it.

Thomas’ comments on Isaacson’s book “The Inovators”, made me pull out Isaacson’s book, “Jobs” and review the sections on Apple 1 and Apple II. I think I understand those products and what went into making them, very well. Thomas’ comments made me want to review the book for faults. I knew that Isaacson had Job’s and Wozniak soldering Apple 1’s, which was incorrect, but wondered what else I would find, if I reviewed those sections. Before I comment on what I found, I will say that I greatly respect anyone that can write such an engaging book, as I don’t have the patience or talent to do it.

Here are the mistakes I managed to find during a quick review of those sections.

  • Page 62: The guy who drew the up the circuit boards didn’t work at Atari. His name was Howard Canton, and he was an independent consultant, who did contract work for Atari and other companies in the valley.
  • Page 67: Woz and the gang didn’t solder Apple 1’s. They were wave soldered in a factory. Assembling the boards really meant stuffing the chips into the factory soldered boards. Daniel Kottke tested the boards, and if they failed, put the failing board in a “bone pile”, that Woz would debug during occasional visits to the Job’s home.
  • Though there are no real mistakes with the Apple II section, there are, in my mind, serious omissions.

  • Page 74: The real problem with the first Apple II PCB layout, was that Howard Canton, instead of doing it himself, had hired someone to do the layout, and that person did a horrible job. The layout was redone digitally, which took, if I remember right, three months.
  • The first Apple II PCB’s didn’t work, do to noise on the address lines that were connected to the DRAM. Rod Holt fixed the problem by adding termination resistors to those lines. This fix was more important than the implementation of a switching power supply. By the time the Apple II was released, switching power supplies had already been in use for 6 or 7 years. In any case, I doubt that use of a linear or switching power supply would have made a great deal of difference in the success or failure of the Apple II. Proof of this, is that the switching power supply is only mentioned in the first Apple II sales brochure, as a one liner in the last page’s technical overview section.
  • Allen Baum had a significant role in developing the monitor for the Apple II, which is not mentioned.
  • Page 84: Though Apple had venture funding, the company was on very shaky financial ground through it’s first year or two. It was not an instant success.
  • In scanning this section, I could find no mention of the Disk II, floppy disk interface. This was a critical item that enabled the success of the Apple II.
  • I understand why Isaacson, in his story, emphasized Job’s interaction with a number of significant personalities. It is a shame that the struggle to develop a new product by a team of talented engineers gets so little “ink”. I also wonder how accurate the depictions of the interactions between the significant personalities really is. It seems that, in terms of the technical stuff that I understand pretty well, Isaacson would grab a fact and elaborate upon it, kind of putting his spin on it, without doing serious fact checking.

    In any case, it’s an entertaining read, that I recommend, in spite of the errors and omissions.

    A Brief Conversation with Woz

    Thursday, May 4th, 2017

    During the Apple/Homebrew reunion, having never met him before in person, I briefly introduced myself to Woz as the guy that makes those Apple 1 clones that he always signing. He said, “nice”. He was surrounded by a crowd of people, so I let it be at that, and moved on. At least I had introduced myself.

    Later on, as I was talking to Daniel Kottke, whom I have known for several years, Woz came over and joined us. We talked about that small change that he thought could add a color to the Apple II. I mentioned that I tried to make that change, but couldn’t make it work, right. He said he knew that. I was a little surprised by this reply, since I don’t think I ever reported that I had spent time experimenting making that change, but failed to make it work well. Maybe, I had emailed him my results and then forgot about it, I don’t know.

    Woz also talked about a change he thought he could have made on the Apple II, that would have saved a chip, but required more complicated software in order to implement video support. I’m not sure what that change would be, but I’m thinking that creating an incompatible Apple II to save a chip isn’t anything I’ll be working on, at least in the near future.

    Woz talked about the video system on the Apple 1. He says he copied it from some terminal product, clearing up that point, once and for all. Part of this video system has a rather complicated state machine that implements the carriage return logic. Woz admitted to Daniel and I, that he never understood that logic. In return, I admitted that I never understood it either. Actually, I was probably being a bit humble, as I understand the concept of that circuit, but never completely understood the details of the implementation. I expect he was saying the same thing.

    Woz finally mentioned that there was one part of the Apple II design that didn’t meet timing specs of the chips. He then said that he knew it, but never told anyone. He was counting on the conservative specs of the chips involved from turning this timing violation into a real problem. I think that he was right, as I have never heard of any timing issues on the Apple II, actually causing problems.

    I wonder if Daniel and I were the first to ever hear this confession, as I don’t recall hearing about it, before. Anyway, this confession reveals some of the difficult decisions that design teams, even the best, have to deal with on a daily basis. Sometimes these sorts of decisions come back to haunt us, and sometimes they don’t. The reason that engineers sometimes hold back on reporting latent issues, is that openly reporting issues may cause endless debate within the design team and possible delays on the project. I’m sure that Woz would have reported it, if he thought it was going to be a real issue.

    By the way, I don’t advocate holding back information from your boss, I’m just saying that it does happen and why.

    Meeting Woz in person, was a real pleasure. He is a great guy, exactly the same in person as when on stage or virtually, via email.

    Apple 1 – byte shop numbers

    Saturday, April 22nd, 2017

    On the back of quite a number of original Apple 1s is scribbled with a felt tip marker, a number, typically 01-00XX. For a long time, it was said that these were supposed to be added by the Byte Shop. A couple of years ago, I ran across a machine purchased from Ray Borill’s Data Domain shop in Indiana, that also had those numbers. This and the fact that the numbers go higher than the 50 that were supposedly sold to the Byte shop made me question the origin of those numbers.

    I had recently heard from a source that Data Domain had purchased machines from the Byte Shop, which could explain how those numbers got on Data Domain computers.

    At last week’s Apple and Homebrew computer club reunion, I happened to start talking to Thom Hogan, who was associated with the Data Domain shop back in the day. I asked him about where they obtained their computers. He said that at some point, they bought Apple 1’s from the Byte Shop, because that Apple would not sell them more computers. They needed more Apple 1’s, because they were selling them into practical applications. They even had one installed at Churchhill Downs, site of the Kentucky Derby. He thought that it was installed near the starting gate for some purpose, though he didn’t exactly remember what it’s function was.

    This explains why the Byte Shop serial numbers could be found on systems purchased from the Data Domain. These two independent sources pretty much remove my uncertainty about the source of the “Byte Shop” numbering.

    How I came to be at the Homebrew/Apple Reunion, LCM+Labs, 2017

    Sunday, April 16th, 2017

    A few weeks ago, I was invited to a “Homebrew/Apple reunion event” at the Living Computer Museum and Lab. Here is some of the text from the invitation.

    Living Computers: Museum + Labs, founded by Paul G. Allen, would like to invite you to a very special private event.

    We are celebrating the opening of our latest exhibit, which follows the first 20 years of Apple Computers, by throwing a party for those who were there. This is a unique opportunity to reconnect to the people, and computers, that you remember from the start of the personal computer revolution.

    I was given no additional information about who was coming or since I never worked for Apple Computers, even exactly why I was invited. However, without hesitation, I accepted the invitation, and made plans to attend.

    Fast forward a few weeks, to just a few days before the event. Someone noticed a little reported article announcing that a very special Apple 1 was going to be on display at the LCM+lab’s new Apple exhibit and brought the article to my attention. This happened to be the computer that I reported in a blog posting a few years ago, though I never updated my Apple 1 registry with this unit. I didn’t think a whole lot more about it, as I have been involved in communications with many Apple 1 owners over the years.

    I arrived in Seattle on Tuesday afternoon for the Wednesday evening event, still unsure why I was invited, and who else would be there. A small bus picked up about 8 or 9 of us from the Hotel late Wednesday afternoon to take us to the celebration. I could not identify anyone on the bus, though everyone was very friendly and in good spirits.

    When picking up my name tag, I saw an impressive number of familiar names on the tags that hadn’t yet been claimed, including Woz and Paul Allen. Anyway, I introduced myself to a number of people and had some interesting conversations, including a chat with Lāth Carlson, executive director of the museum. However, I still was unsure why I was invited. I was taking the approach of “when in Rome, act like a Roman” – in other words, I was just trying to fit in and not ask too many questions.

    After a bit, we were led through a behind the scenes tour. As we were watching the Bendix vacuum tube computer G-15 being demonstrated, someone that I didn’t recognize, saw my name tag and said “Mike Willegal is here”. The people identified themselves as the Hutmacher family and told me that they had donated the computer to the museum. The donation was kept a secret, which is why I wasn’t told anything. The Hutmacher family had asked the museum to invite me to this celebration, since, with the help of some acquaintances I had with early Apple people, I helped them verify the history of the computer and also pointed out that it belonged in a museum. The mystery of why I was there, was solved.

    The fun part of being identified by the Hutmacher family is that they made a big fuss over me, and some of them had their pictures taken with me. During all this fussing over me, Chris Espinosa, who I had never met and only could identify by the name on his badge, looked on from the background with a puzzled look on his face. I could almost see his brain working – who is this guy that they are making such a fuss over. After the Hutmacher family moved on, I introduced myself to Chris Espinosa and explained what had happened.

    Lastly, kudos to the Hutmacher family, a very special group of people, for putting a very special Apple 1 into very good hands.

    One of WOZ’s Wonder Powers…

    Thursday, April 13th, 2017

    Do to the acts of an extraordinary generous family, I was invited to a private gathering of micro-computer legends at the “Living Computer Museum” in Seattle, earlier this week. The gathering included a number of people that were involved with the Apple 1 while it was still based out of the Job’s home and others that were involved in the early days of the personal computer revolution. It was a gathering that, as long as my brain is functioning, I will never forgot. During this event, I learned several little stories and will share them in the coming days on this blog. Here is the first story.

    While several of us were admiring the original Apple 1 that will be available to visitors to the museum to use, we discussed how it was being booted with the museum staff. Inevitably, the topic turned to how WOZ used to enter the 4K of BASIC object code by typing hex codes using the Apple 1 monitor. Several of the people there, said they witnessed him do it, and confirmed his amazing prowess at data entry through a keyboard.

    Let me tell you, when I first built an Apple 1 clone, I tried to replicate the feat and gave up after screwing up a few hundred bytes worth of input. This was so difficult for me, that I found it hard to believe that it could be done. At the time, I sent an email directly to Woz to ask him about it. He responded that he did it all the time.

    I can’t find any blog post that reported this exchange. I may have made one or perhaps, I was so dubious, that I decided to file the whole episode away. Anyway, hearing directly from a couple of eye witnesses has eliminated any remaining doubt and I’m rectifying any omissions in faith by making this post.

    I can’t remember hearing about anyone else achieving this, but assume it’s possible. I’ll bet it’s not something that anyone else has done repeatedly. This is a difficult feat, and the fact that WOZ did it repeatadly makes it simply amazing.

    PS/2 Adapter Software and Hardware CAD Files Now Available for Free Download

    Monday, December 26th, 2016

    Go to my PS/2 adapter web page to find the links.

    Support will be very limited. The firmware is actually rather sophisticated for what this device does. Understand that it is completely in assembler, and if you desire to make changes, it would be best if you were familiar with coding in assembler for micro-controllers.

    Some scripts are included in the software package that are used to download the firmware, calibrate the built in RC oscillator and burn the fuses using a USB programmer called AVRdude. Fuses and EEprom must be programmed correctly or the micro-controller may not function correctly. The A version of the Atmel at tiny 2313 has not been tested. I have been using ATTINY2313V-10PU.

    The CAD program I used to create the PCB is called Osmond PCB. I have also included GERBER and Postscript files. You must accept all risk associated with creating PCBs using any of these files.

    End of an Era for Me

    Saturday, December 17th, 2016

    As look back at some of the blog postings I made during the early days of the Mimeo project, the excitement I felt, could be easily discerned. For better or worse, after nearly 7 years, that excitement is no longer there, and it’s time to move the project over to someone who has a strong passion for that landmark system.

    I’ve transitioned Mimeo 1 sales to Corey Cohen. I’m sure he will do a great job selling and supporting people interested in building reproduction Apple 1 Computers.

    Since first making them available in March of 2010, I’ve sold 167 Mimeo PCBs, the first few as part of a kit, even a few that were completely assembled and tested. I have greatly enjoyed the entire process from creating the PCBs in the first place, to fixing a few boards that customers needed help with. Especially gratifying, has been the great relationship that I have established with all the people that I have made contact with over the years. One thing that I never expected, when starting this project, was the amazing contacts I made with so many people associated with Apple during those early years.

    However, the learning part of the process, which is one of things that keeps me interested in my hobbies, has not been there over the past few years. It is time to move the sales over to Corey, who has unbelievable enthusiasm and knowledge for and about those milestone computers.


    I will continue to sell SCELBI PCBs, as I am still excited about working on that system and learning a lot, while doing it. Blog followers will know that the Oscilloscope Interface PCBs, the last SCELBI boards that need to be reproduced, will soon become available to interested parties. I have some ideas for some even more obscure reproduction vintage computer projects. However, the Oscilloscope interface must be completed, before I move on to those projects.

    Other Products

    Other products I have sold in the past, will only be continue to be sold if I have remaining inventory in stock.

    I presently have stock of the following

  • Brain Boards
  • Swift Cards
  • I am sold out of the following:

  • Apple II, rev 0 boards
  • SuperProto boards
  • PS/2 keyboard adapters.
  • Datanetics Keyboard PCB
  • The PS/2 Keyboard Adapter

    The PS/2 keyboard adapter is a little bit of a special item to me. When I had those PCBs made, because of economies of scale, I had 150 fabricated. I never thought I’d sell all of them. In the end, I sold over 140 those little dongles, using the others for a number of my own special projects. Though they probably exist, I have never heard of a PS/2 keyboard that it didn’t work with. It was designed to operate with Apple 1 and Apple II computers. As I originally hoped, people adapted the design to a number of systems beyond that. The firmware has had minor firmware features and improvements made over the years, but the basic design hasn’t changed over all these years.

    There have been a number of other PS/2 keyboard to parallel ASCII keyboard adapters designed over the years, some coming before, and inspiring my adapter. Though it could certainly be improved further, I sincerely believe my version is currently the best of the breed.

    When I get the time to add them to my web site, I will be releasing to the public domain, with no restrictions, all design files, including firmware and PCB CAD files. You will be able to do what you want with it, make copies for sale, improve it, or just study the design for your own purposes.

    Using an Apple Powerbook as a Cassette Tape Recorder

    Sunday, September 13th, 2015

    During my debug of the SCELBI cassette tape interface, I decided I needed to get better visibility to the actual output of the cassette interface. There are a couple of ways to do this. One way was to use a DSO (digital storage oscilloscope) or logic analyzer to capture and analyze the signal. I don’t have either, so I had to resort to a second method. That is to capture the cassette output as an audio clip using an audio recorder and editor on a personal computer. One such application is Audacity, which is a free download.

    The only trouble with using a modern personal computer is getting the audio clip into the PC. Apple Powerbooks include a headphone port that includes speaker out and microphone in. Wendell Sander has an Apple 1 site that includes directions on connecting an Apple 1 to an iPod’s headphone port. I did a bit of research and determined that the Powerbook headphone port is basically the same.

    I constructed a dongle based on Wendells directions and hooked it up to an Apple IIe for testing. Unfortunately, I found that the Powerbook didn’t recognize the microphone input. After some more web searches I found a couple of sites that indicated that a 1600 ohm resistor between microphone in and ground would cause the microphone to be recognized. I hooked up a 1500 ohm resistor and found that it worked most of the time. The next larger size resistor in my stash was 2K ohms, so I switched to that and found that it worked reliably. I tested with the Apple IIe and found I could read and write reliably. I also decided to add a .1 uF capacitor on the microphone input line to decouple it.

    I next switched to the SCELBI to capture the output of the SCELBI write card. This proved very helpful and with the help of the Audacity audio editor, I was able to zero in on the problem I was having. During the examination of the SCELBI cassette signal I noticed that the high frequency tone was greatly attenuated. This was due to the .33uF capacitor suggested in Wendell’s notes. The SCELBI uses much higher frequencies than the Apple. I needed to change the capacitor to .01uF so it didn’t attenuate the 2700 Hz high frequency signal used in the SCELBI cassette interface. The resulting circuit is depicted below.

    powerbook cassette adapter circuit

    powerbook cassette adapter circuit

    Here is a picture of the dongle. Note that I took a 4 conductor patch cord and cut it in two for the plug end. The reason is that the small clearances in 4 conductor plugs are difficult to solder cleanly. It was much easier to cut the wire and solder the wires and components together.

    Powerbook Cassette Interface Dongle

    Powerbook Cassette Interface Dongle

    And here is a screen shot of the Audacity application showing a piece of SCELBI cassette audio out. The higher frequency portions represent ones, and the lower frequency are zeros. It takes 2 cycles of low frequency or 4 cycles of high frequency to represent a single bit. This encoding method is called frequency shift keying or FSK.

    SCELBI Cassette Clip

    SCELBI Cassette Clip

    An Apple with a Very Interesting History

    Friday, August 21st, 2015

    My web site doesn’t draw the number of hits that many more popular sites do, but my site occasionally attracts some emails that turn into very interesting stories. The discovery of John Draper’s Apple II is one of them, and I need to put together a few more posts in order to describe his system and it’s history. However, right on the heels of the discovery of Draper’s Apple II, another very interesting system has just surfaced which is housed in this enclosure.

    Apple Case

    Apple Case

    The story is that it was taken out of Steve Jobs office by Apple employee and manufacturing engineer, Don Hutmacher, after Steve was fired in the mid 80s. The story goes that Don was allowed by his boss to go into Steve Job’s office take anything that was left over. It had been picked clean by the time that he got there. He noticed this computer and a bag of Starbucks coffee, and that is how he ended up with it.

    More to come…

    Apple 1 Registry Updated – One of Which May be Myth Destroying

    Sunday, June 14th, 2015

    This update is way past due, I had knowledge of some of the new units since last fall. Three new Apple 1’s are listed. The most interesting is number 1-0052,owned by James Coble. His story seems to shatter the myth that the Byte Shop, not Apple, added the serial numbers on the units in the first batch. There were some issues with that story before, but this information seems to completely shatter it. I have a sent a query out to some experts to see if they can comment on what James has to say. Stay tuned for an update.

    Another interesting note is that the unit that was sold on ebay is reported to be going to Germany. The world-wide market for Apple 1 continues to be stronger than the domestic US market. I think the Ford Museum purchase might have been an anomaly.

    Lastly, I’m pretty skeptical about the report from the bay area about an Apple 1 being given to a recycler. That unit is not going to get mention in the registry until far more concrete details (like a picture) are revealed.