Apple II History Part 2: The Apple I

@SteveJobs

Published in

Apple II History

· 5 years ago

Compiled and written by Steven Weyhrich
(C) Copyright 1991, Zonker Software

(PART 2 -- THE APPLE I) [v1.1 :: 12 Dec 91]

THE APPLE I: DEVELOPMENT

At the Homebrew Computer club in Palo Alto, California (in Silicon Valley), Steve Wozniak, a 26 year old employee of Hewlett-Packard and a long-time digital electronics hacker, had been wanting to build a computer of his own for a long time. For years he had designed many on paper, and even written FORTRAN compilers and BASIC interpreters for these theoretical machines, but a lack of money kept him from carrying out his desire. He looked at the Intel 8080 chip (the heart of the Altair), but at $179 decided he couldn't afford it. A decision to NOT use the 8080 was considered foolhardy by other members of the club. Consider this description of the microcomputer "world" as it was in the summer of 1975:

"That summer at the Homebrew Club the Intel 8080 formed the center of the universe. The Altair was built around the 8080 and its early popularity spawned a cottage industry of small companies that either made machines that would run programs written for the Altair or made attachments that would plug into the computer. The private peculiarities of microprocessors meant that a program or device designed for one would not work on another. The junction of these peripheral devices for the Altair was known as the S-100 bus because it used one hundred signal lines. Disciples of the 8080 formed religious attachments to the 8080 and S-100 even though they readily admitted that the latter was poorly designed. The people who wrote programs or built peripherals for 8080 computers thought that later, competing microprocessors were doomed. The sheer weight of the programs and the choice of peripherals, so the argument went, would make it more useful to more users and more profitable for more companies. The 8080, they liked to say, had critical mass which was sufficient to consign anything else to oblivion."<1>

Another chip, the Motorola 6800, interested Wozniak because it resembled his favorite minicomputers (such as the Data General Nova) more than the 8080. However, cost was still a problem for him until he and his friend Allen Baum discovered a chip that was almost identical to the 6800, while considerably cheaper. MOS Technology sold their 6502 chip for $25, as opposed to the $175 Motorola 6800. Wozniak decided to change his choice of processor to the 6502 and began writing a version of BASIC that would run on it. A friend over at Hewlett-Packard programmed a computer to simulate the function of the 6502, and Wozniak used it to test some of his early routines. When his BASIC interpreter was finished, he turned his attention to designing the computer he could run it on. Except for some small timing differences, he was able to use the hardware design he had earlier done on paper for the 6800.<2>

To make the computer easier to use, Wozniak favored a keyboard over the front panel switches that came on the Altair. He also made it simple to use a television for a video terminal. (Recall that at this time the most common mechanism used for input/output was a teletype, which consisted of a keyboard, typewriter, and if you were lucky, a paper tape reader/puncher). Functionally, it was a television terminal attached to a computer, all on one printed circuit board (another enhancement over the Altair). Wozniak used two 256 x 4 PROM (programmable read-only memory) chips to create a 256 byte program (called a "monitor") that looked at the keyboard when the computer was turned on. This monitor program could not do much more than allow entry of hex bytes, examine a range of memory, and run a program at a specific address.<3> (The Altair needed these "bootstrapping" instructions to be entered by hand each time the computer was turned on).

Because there were no cheap RAMs available, Woz used shift registers to send text to the TV screen. Consequently, his video terminal was somewhat slow, displaying characters at about 60 characters per second, one character per scan of the TV screen. (This speed would be similar to watching a computer communicate via a modem at 1200 baud). It was slow by 1991 standards, but an advancement over the teletypes that could only type 10 characters per second. The computer had 8K of dynamic RAM. You could load BASIC into 4K of memory and have 4K left over for your own programs. It had a video connector, but you had to connect a monitor on your own. You also had to buy the keyboard separately and wire it into a 16-pin DIP connector. The power supply had to be connected to two transformers to get 5 volts and 12 volts for the motherboard. There was no speaker, no graphics, and no color. There was a single peripheral slot, and when it was first released there was nothing available to plug into this slot. It was entirely contained on a single printed circuit board, about six by eight inches in size (most hobby computers of that time needed at least two boards), used only 30 or 40 chips, and because it could run BASIC programs it got people's attention.<4>

THE APPLE I: MARKETING

Let's adjust our time circuits for 1976, and jump forward in time. By now, Steve Wozniak had completed his 6502-based computer and would display enhancements or modifications at the bi-weekly Homebrew Computer Club meetings. Steve Jobs was a 21 year old friend of Wozniak's and also a visitor at the Homebrew club. He had worked with Wozniak in the past (together they designed the arcade game "Breakout" for Atari) and was very interested in his computer. During the design process Jobs made suggestions that helped shape the final product, such as the use of the newer dynamic RAMs instead of older, more expensive static RAMs. He suggested to Wozniak that they get some printed circuit boards made for the computer and sell it at the club for people to assemble themselves. They pooled their financial resources together to have PC boards made, and on April 1st, 1976 they officially formed the Apple Computer Company. Jobs had recently worked at an organic apple orchard, and liked the name because "he thought of the apple as the perfect fruit--it has a high nutritional content, it comes in a nice package, it doesn't damage easily--and he wanted Apple to be the perfect company. Besides, they couldn't come up with a better name."<5>

Jobs approached the owner of a new computer store in the bay area called "The Byte Shop." This businessman, Paul Terrell, expressed an interest in the Apple Computer (to be known later as the "AppleI"), but wanted only fully assembled computers to sell. If they could provide this, Terrell told them he would order fifty Apples, and pay cash on delivery. Suddenly, the cost of making (and selling) this computer was considerably more than they expected. Jobs and Wozniak managed to get the parts on "net 30 days" (30 days credit without interest), and set themselves up in Job's garage for assembly and testing of the AppleI. After marathon sessions of stuffing and soldering PC boards, Jobs delivered the computers to the Byte Shop. Although these "fully assembled" computers lacked a power supply, keyboard, or monitor, Terrell bought them as promised. In July of 1976 the AppleI was released and sold for $666.66, which was about twice the cost of the parts plus a 33% dealer markup.<6> Two hundred AppleI computers were manufactured, and all except twenty-five of them sold over a period of ten months.<7>

Although the AppleI was easier to begin using than the Altair (thanks to its built-in ROM code), it was still a time consuming process to set it up to do something useful. Steve Wozniak would have to type in about 3K of hexadecimal bytes before BASIC was ready to use. He could do it in about 20 to 30 minutes, but he almost knew the code by heart. The typical user was more limited in ability to use BASIC on the AppleI. To broaden the appeal of the AppleI (and at the insistence of Paul Terrell), Wozniak designed a cassette interface. It was mounted on a small two-inch-high printed circuit board and plugged into the single slot on the motherboard. The card sold for $75 and a cassette tape of Woz's BASIC was included with it. The advertisement Apple included with the card stated, "Our philosophy is to provide software for our machines free or at minimal cost." The interface worked, but worked well only with cassettes running on expensive tape recorders. To further try to enhance sales, the Byte Shop stores found a local cabinetmaker that made some koa-wood cases for the Apple computer (so it would no longer be just a "naked" circuit board).<8>

Interestingly, although most of the action in the micro world was going on in Silicon Valley, news of the AppleI made its way east. Stan Veit, owner of the east coast's first computer store, bought an AppleI and took it to a meeting of the Association of Computer Machinery. Those attending were quite skeptical that a REAL computer could fit into a small briefcase; they were sure that the machine was just a portable terminal, attached by a hidden phone line to a mainframe somewhere!<9>

NEXT INSTALLMENT: The Apple II