Apple I Replica Creation -- Foreword

Steve Wozniak


It was in sixth grade that I got my first transistor radio. That may have been the most important gift of my life. I found out about music and I knew that it was a big thing in my life, all from this small hand held, 10-transistor radio. I could sleep with music all night long, and did so that entire year. My father was working on missile guidance technology for military projects around this time, and showed me how tightly they could pack transistors and told me how chips were coming with more than one transistor on them, for even more space and weight savings. I commented that they were designing these things to make better and smaller radios and he told me "no," that they were being designed for military and commercial uses and that only after a long time they'd filter down to consumer products that we used in our lives and homes. That thought bummed me out, that normal people in their homes wanting good products were not driving technology.

My introduction to electronics was accidental. I lived in a new community surrounded by orchards. It was Santa Clara Valley but is now called Silicon Valley. I had lots of local electronics-kid friends and we'd do gardening to be paid in parts like resistors. I read a book about a ham radio operator solving a kidnapping and found that anyone of any age could be a ham. You didn't have to be older as with car licenses. So by sixth grade I had my ham license and was learning electronics, back in the days of tubes.

One day I stumbled across a journal in a hall closet at home. It had articles about early computing projects. This was around 1960 when computers were unknown to mortals and filled entire rooms. I read articles on strange storage devices and Boolean algebra and logic gates and how they could be combined. What amazed me most was that none of this stuff was too hard for a fifth-grader to follow. You didn't need advanced math to understand binary arithmetic or logic gates. I became fascinated by what I'd stumbled onto. Based on what I'd read and what my father could teach me I had a couple of large science fair projects in sixth and eighth grades with hundreds of transistors and diodes and all doing logic. One played tic-tac-toe, which I thought was a game of logic (I now know that it's more a game of psychology). The other project added and subtracted 10-bit numbers. I had no idea that I was on the right path to learning how to design computers, or that there were jobs in this field. In fact, I was on a search to find out what a computer was. I myself was too shy to ask or read to get such answers.

At another science fair I stumbled onto a project with a stepping motor advancing a pointer to switches where you could set up operations to be done. This motor could loop, or back up, depending on results. This was the first time in my life that I learned computers had instructions to do things like my adder/subtracter did, and that it could repeat those instructions.

We had no computer at our high school, but because I was so advanced by then in electronics my teacher, John C. McCullum, a great teacher, arranged for me to learn more by programming a computer at a company in Sunnyvale. In those days just the word "computer" brought looks of awe. I came to love all that I could do in Fortran that year. I also stumbled upon a manual at Sylvania titled "The Small Computer Handbook." It described a real minicomputer, the PDP-8. The engineers let me have that manual and it changed my life forever.

Now I had a manual describing a real computer, its architecture and instructions. I also had some chip catalogs, back when you could only get one gate on a chip. And I had my knowledge of how to combine gates into things like adders. So for the rest of high school my favorite pastime became designing minicomputers on paper. When a single chip cost $50 (maybe that's $500 today), you don't have the parts to build your own computer. I found how to get manuals describing various minicomputers from Digital, HP, Varian, DEC, and others. I designed my own versions of these machines over and over. As chips got better, my designs took fewer and fewer parts. My goal became to beat my prior design whenever I redesigned the same computer again. I got very skilled at digital design this way. I had no endpoint; you can always think of one more way to save another chip in a design.

I had no friends, parents or teachers doing this with me, or even aware that I was doing it. My computer designs were weekend projects in my room with my door shut. I sometimes would go late into the night and it helped to drink Cokes. When the Data General NOVA was introduced, and I finally got around to designing this computer, I found that it took half as many chips as my other designs due to its unique architecture. That changed my life a lot too. If you design a computer architecture based on what chips are available, it can save a lot of parts.

All these minicomputers had front rectangular plates full of switches and lights, and they were intimidating and commercial-looking and belonged in racks on factory floors. But if they could run Fortran, that could even enable a mere mortal to use them to play games and solve problems. I knew what I needed and told my father that someday I'd have a 4K NOVA computer. When he pointed out that it cost as much as a house I said I'd live in an apartment, but I'd have my own computer someday.

I could design computers but couldn't afford the parts to build them.

After some college, I wound up designing chips for HP's early scientific calculators. I worked on a lot of interesting side projects but lost track of minicomputers and overlooked the introduction and advancement of microprocessors. In 1974 I saw my first Pong game in a bowling alley. As I stared, mesmerized, at the screen, it occurred to me that I could build a Pong. I could never afford an output device, but like everyone else, I had a color TV at home. There was no video-in jack, but in those open days you got schematics with your TV. I knew TV signals and how they worked from high school electronics, and I knew digital design, so it wasn't long before I built my own Pong, using very few chips.

Later in 1974 I visited an old friend, famous phone phreak John Draper, also known as Captain Crunch. He was typing on a Teletype, an input/output device that I myself could never afford. He was playing chess with a computer in Boston. Then he showed me how he could have the Teletype type out a list of computers and he could switch to one at Berkeley. It was the early ARPANet and you dialed into a number at Stanford using a modem to get onto it.

I absolutely had to do this thing that made you like a king, doing what nobody else could do. I had just built my Pong and knew how to get signals onto a TV screen. So I designed and built a terminal that could put letters and numbers on my home TV. I had to buy a keyboard for $60, and that was very expensive for me but was barely affordable. I did indeed access the ARPANet a few times, but wasn't as interested in using those computers as I was just knowing that I could reach out to such distant places. It was like ham radio, and also like phone phreaking, in that sense.

So a $60 upper-case-only keyboard and my Sears color TV gave me the input/output I needed at an affordable cost. Steve Jobs said "Let's sell it," and we did sell a number to a local timeshare outfit called Call Computer.

In 1975, the Homebrew Computer Club started. I got tricked into going. I never would have gone to something based on microprocessors because I didn't know what a microprocessor was. I didn't know that you could buy an enhanced microprocessor, a CPU, in a case called the Altair. I didn't know that you could add enough to this processor to make it a computer. I was told that a new club was being formed for people with terminals and the like. I figured it would be a great chance for a shy guy to show off with his own video terminal based on very cheap chips.

I got scared the first night at the Homebrew Computer Club. Everyone knew what was going on with these new affordable 'computers.' I took home a microprocessor data sheet and to my surprise this chip was the CPU that I'd grown up designing in high school. I was back in business. I saw that night that soon I'd design or buy a 4 KB computer and run Fortran for myself finally.

Rather than design a computer from scratch, I saw a shortcut. I could take my terminal with human input and output, and combine it with a microprocessor and some RAM. I'd actually built a computer of my own design five years earlier, one equivalent to the Altair with 256 bytes of RAM and switches and lights on a front panel. I didn't want to do that again. I didn't need to wire dozens of switches and have the chips to get them to the memory of a computer. That took too many parts, and chips, and money. Our calculators at HP had ROMs, and they ran a program when you turned them on that waited for a user to press human buttons, and then the program did the right things. I saw that I could write a short program that monitored the keyboard for input to do what the old front panels had done. I called this program a monitor. It took 256 bytes, which was 2 PROM chips in 1975.

I first got working what was to be the Apple I, using static 1K RAM chips. But it took 32 of these chips to have 4 KB of RAM, enough for a computer language. The 4K dynamic RAMs were just being introduced, the first RAMs to be cheaper than magnetic core memories. I bought some from a fellow at our club and got them working on my computer. I had to design some refresh circuitry, but overall I saved so many chips and dollars that it was the right way to go. If you look back, you'll find that every single other hobby computer back then used static RAMs because they involved less design work.

I passed out schematics and code listings freely at our club, hoping that others would now be able to build their own computers. It took another four months for me to write BASIC for this computer. I'd never studied computer language writing, but figured out good approaches for that. Steve Jobs said that there was a lot of interest in having computers but not in wiring them up, so why don't we start a company to make PC boards for $20 and sell them for $40. We'd have our own company and all. Steve came up with the name Apple Computer. I sold my most valuable possession, my HP-65 calculator. We came up with a few hundred dollars and started this company.

After the PC board was done, Steve struck up a partnership with Paul Terrell at the Byte Shop, the only computer store in our region, to sell fully-built and assembled computer boards for $500 each. I was into repeating digits so we priced it at $666.66 retail.

We did not make or sell a lot of Apple I computers over the next year, but we had other jobs. We did get our name and computer characteristics in many articles over that year and it was easy to see that Apple Computer was getting very well-known in some circles.

I look back on my Apple I design and actually have trouble figuring out some of it. My designs back then were sometimes too clever to figure out. They were designed to save parts and cost.

The Apple II was really the computer designed from the ground up that would kick off personal computing on a large scale. But the Apple I took the biggest step of all. Some very simple concepts are very hard to do the first time. This computer told the world that small computers should never again come with geeky front panels, but rather with human keyboards, ready to type on. After the Apple I, Processor Technology introduced the SOL computer, and it also came with a keyboard and monitor and became the hottest selling Intel-based hobby computer, selling thousands a month. Contrast that with the Apple I, of which we sold maybe only 150. The Apple II was to be the third low-cost computer to come with a human keyboard.

—Steve Wozniak
January, 2005

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