Skip to main content

A pioneer looks back

Nov 23, 2015 01:26PM, Published by J. Chambless, Categories: Local History, News, Today

John Blankenbaker of Chadds Ford, with the 1970 circuit board for his Kenbak-1 computer and his home desktop.

By John Chambless
Staff Writer

John Blankenbaker was born in 1929 on an Oklahoma dairy farm.

As a boy, he would lie in the grass outside his house on summer nights and ponder the stars. “I did have an interest in the physical world. I was impressed by the stars,” he said. “And I remember wondering why a jar of water would disappear through evaporation.

“Then I did a little experiment once – I wondered what was inside a .22 bullet,” Blankenbaker said, smiling. “So the thing to do is take it apart, and for that purpose, a hammer was as good as anything. So I beat on a .22. It went off and hit a cast-iron kettle out in the yard, I think. It made a lot of noise. Everyone was running around the house.”

Today, at 85, Blankenbaker has seen the world change in just about every respect. In the tidy living room of his Chadds Ford home, he has three large circuit boards and some papers that attest to the role he played in building what the Computer Museum in Boston has called “the world's first commercially available personal computer.”

Admitting that he doesn't have a cell phone and uses his desktop computer primarily for doing genealogical and historical research, Blankenbaker shows a quick mind and a clear memory, and he traces his path through the technological leaps and bounds of the last century with a self-effacing tone.

“The first time I saw a real computer was SEAC at the Bureau of Standards in Washington, D.C.,” he said. “It occupied a building that was larger than my house. It was built just for the computer. One of the things they had to include was air conditioning, because it generated a lot of heat. This was in Washington in the summer, so it was a pleasant place to work. I worked there as a summer job in 1951.”

In those days, no one had their own computer. Universities and research institutions maintained the room-filling computers of the day, and outside parties had to line up for a time to run their research.

“It had been working for a while, but they were still discovering little flaws in the design,” Blankenbaker recalled. “They were still fine-tuning it. There weren't too many working computers at the time. The ENIAC was working for the Army down at Aberdeen. And SEAC was operating, and there was SWAC out at UCLA.”

John Blankenbaker, circa 1971, with his Kenbak-1 personal computer.

 The computer was so busy that private individuals weren't authorized to use it, “except during thunderstorms,” Blankenbaker said. “It was so unreliable that, during a storm, the didn't want to risk a big project, so private individuals could try a personal program.” One problem with the SEAC was that operators couldn't tell what it was doing when it was working. “Oh, you couldn't tell anything,” Blankenbaker said. “The input was on paper tape, and you normally read in the entire problem. It computed and then it punched paper tape and you printed it to see what it said. The language was strictly zeroes and ones. It looked like gibberish.”

Blankenbaker, who was one of four students who got to work with SEAC, wrote a program for it that didn't work. The engineers didn't know why, since it looked fine.

Before that summer, in 1946, Blankenbaker had enlisted in the Navy at 16 to learn how to repair the increasing amount of electronics aboard ships. When he was a college freshman, “I happened to read an issue of Popular Science or Popular Mechanics, and it was probably about ENIAC. It had 17,000 tubes. And the number system only had a zero and a one. In those days, people never heard of things like that. I spent some time figuring out how you compute, how you convert to numbers that you understand.

“My motivation was that we had to do a fair amount of computations in the physics lab, and I thought maybe I could automate it,” Blankenbaker said. “I spent a lot of time, using relays, trying to design something more like a calculator. I started adding up the cost, though, and it was well beyond my budget, so I abandoned it.”

After college, he went to work on airborne computer navigation systems for the Hughes Aircraft Company in 1952. “It was only suitcase-size,” he said. “I remember at the time that one man said, 'Someday planes will be flown by computers, and they'll have a man who just looks like a pilot to keep the passengers calm.' I said that was crazy.”

Then he worked on a business data processor at Hughes. That project eventually ended when the manager asked how many units they could possibly sell. “The guess at the time was that maybe 20 computers could meet the needs of the country,” Blankenbaker said, laughing. “So he said he didn't think there was enough profit in that and he canceled it.

“I've always, throughout my career, underestimated the future,” he said. “I never saw the future clearly, much to my regret now. There were many investment opportunities along the way, you know? I thought some things were clever work – like this Xerox machine that made copies. What I should have thought about was, 'Where do I buy some stock?'” he said, laughing.

An early ad for the Kenbak-1, and the interior of the original unit.

 After being associated with the burgeoning computer field for so many years, in 1970, “I was unemployed and had some extra money,” Blankenbaker said, so he decided to start tinkering with building an affordable personal computer in his California garage. He recruited his brother to help lay down the tape that would become the initial two-sided circuit boards.

The resulting unit, which he dubbed Kenbak-1 (a shortened version of the middle of his name), had 130 integrated circuits and 256 bytes of memory. That amounts to 1 byte for each letter. The input was done by eight switches, and the output was indicated in eight lights. It was priced at $750.

In those days, people simply didn't see how a computer would be of any use to them. “Even if you'd wanted one, you'd have to go down to the bank and negotiate a loan,” Blankenbaker said.

He pulled out a paper that was distributed with the Kenbak-1 and showed how you could program information into the unit with a series of numbers that stood for commands. It worked on “machine language,” he said, and could do simple computations, such as determine the day of the week if you input the month, date and year. The unit was marketed to schools, a decision which Blankenbaker now regrets, because of the 40 machines he managed to sell, he had to wait for school funding processes to get any payment. “I should have gone after the hobbyist,” he said.

A circuit board for the Kenbak-1 was put together by John Blankenbaker and his brother.

 With only three employees at the peak of his company, Blankenbaker went out of business and sold the units to CTI Educational, which didn't do much better with them. The problem was that technology was changing so rapidly in the 1970s. “The thing that made computers possible was not the microprocessor, it was the memory. That's been the key factor,” he said.

Of course, another garage in California held the men who would start Apple Computer in 1976 and change the world forever. Steve Jobs and Steve Wozniak met at the Homebrew Computer Club, a group of computer enthusiasts who met to swap ideas in Menlo Park. “Sometime before the Apple computer came out, I was invited to go up there to demonstrate my computer,” Blankenbaker said. “I've often wondered if some of the people there saw what could be done, but I don't know. I don't have a guest list or anything to know who was there.”

That fateful meeting may have given Jobs and Wozniak some pointers, but it didn't lead to Blankenbaker becoming a billionaire. “I don't have a problem with that,” he said with a shrug. “I'd do the same thing, too. I'm not feeling bad about it.”

This Kenbak-1 was auctioned for $28,000 last summer.

 Several years ago, one of the first Apple 1 computers – housed in a homemade wooden case – sold for more than $904,000 at auction. That got Blankenbaker thinking, and he restored his only remaining Kenbak-1, the prototype, to working condition and auctioned it through Bonham's last summer. It brought $28,000, which was nice, but hardly life-changing. “I had dreams and visions of what it might bring,” he said. “Mine was five years ahead of Apple.”

There are perhaps 10 remaining Kenbak-1 computers in collections around the world, he guessed. They were durable, but the problem in restoring them is a lack of parts. “There's one guy in Canada who has a few, but I'm not sure if they work or not,” Blankenbaker said.

After his computer venture fizzled, Blankenbaker worked for a company working on a pioneering method of sending voice to digital through a phone line, and recreate the voice on the other end of the line. “At the time, that was about 9,600 bits per second, the most you could send down a telephone line. That's nothing today. But the voice quality was poor,” he said. “It didn't pick up certain sounds, and they never sold enough systems to make a profit.”

Blankenbaker was a relatively early adopter of computers and bought his first desktop in 1980. He is dazzled by what computers have become. “It's hard to believe the increase in the amount of data that can be transmitted,” he said.

His wife has an iPad, “but she uses it to play Scrabble with her daughter. I don't use it,” he said. He regards computers as great tools, but fraught with great peril. “Cyber threats are scary, and the other big question is privacy,” he said. “The net result is that privacy is going to be eroded. You're going to have to live as if the world knows everything you do, and it's stored somewhere.

“Technology is not everything it's cracked up to be,” he said. “It's got a negative side to it.”

To contact Staff Writer John Chambless, email

Like what you're reading? Subscribe to West Chester & Chadds Ford's free newsletter to catch every headline