(I spent the day of Nov. 1 visiting Central High School, my alma mater, in Philadelphia and talking to students. I was late and missed the first period, so I'm posting here what I would have said. Some alumni friends have commented on my failure so far to make much mention of Central and the part it played in my development, so this is my attempt to remedy this oversight. - LF)
To the Students of Ms. Henry's 1st period Physics Class at Central High School
16 Nov. 2009
First, allow me to apologize for failing to show up at your class Nov. 1 as I had promised – there were serious delays on the regional SEPTA rail lines, but if I had followed the Silicon Valley adage “if you're not ten minutes early, you're five minutes late” I would have had plenty of time to meet with you. While I could not speak to you directly I can use this essay to say what I would have said in class, and you will be able to pose questions as comments.
I have spoken to 11th grade students at Central before and once someone was candid enough to ask me “why should we listen to you?” This is a legitimate question, so I will try to answer it. I'm an electronic design engineer who was involved in designing some of the first personal computers. There are many ways to define “personal computer”, but I focus on the ways in which the user interacts with the computer.
In 1974 the newest small computers were called “minicomputers”. They were table-top sized boxes with a lot of switches and lights on their front panels. There was no screen or keyboard – those were on a separate device called a “terminal” that was plugged into the computer. The terminal had its own memory holding the data displayed on the screen, since the screen displayed but did not store data. The computer had its own idea of what data should be displayed, and it had to describe that data and transmit that description through the wire. The terminal would interpret this description and place the intended data in its display memory.
This would all take time and limited the speed with which the computer could interact with its user. The terminal might cost $1500 – quite a bit more in today's dollars - but the computer cost a minimum of $5,000, so the extra amount wasn't too significant. However, when the “minicomputer” became a smaller and cheaper “microcomputer” due to microprocessor technology, the cost of the terminal began to exceed the cost of the computer.
In 1974 I was working with a small group in San Francisco trying to put into service an “electronic bulletin board” that would be accessible in public places – the idea of having a computer in the home was then considered a matter of outlandish science fiction. We needed terminals that could be kept working by the people who used them, or by people they knew. I realized that the TV or a similar video monitor – like a closed circuit TV monitor – could be used as the terminal display. I also realized that the important element was not the microprocessor, which wouldn't be needed for a terminal, but the improved memory chips that were then appearing.
Using these “random-access memory” chips would be more expensive than using the chips common to terminals of the time, but I saw that if you started with the new chips you could build within a structure that could be expanded later into a computer. I wrote up an engineering specification for this kind of computer, printed it up and sold it to members of our small circle of enthusiasts for 25 cents. The structure described by this specification was a combination of computer and terminal with a display memory that was part of the main memory of the microprocessor.
This “shared-memory” architecture allowed for the very fastest interaction possible between the computer and the display – there was no more wire connecting the two and no description language to deal with. Suddenly you could have software that changed things all over the screen simultaneously, and you could now create and run computer games! And best of all, the cost of this high-performance combination terminal and computer was less than the old way of doing it.
I designed a circuit board that could be plugged into the early 1975 personal computer kits giving them this capability, and it was so successful that it was widely copied and became the ordinary way personal computers were built. So you can see, I could claim to be the inventor of the personal computer, if my definition of “personal computer” were widely accepted. Of course, if it were accepted I would still not get money in the mail, so I don't pursue the issue.
I do want to explore the question of why I found myself reaching the conclusions I did when I did. To do this, I need to ask a question – what is the difference between scientists and engineers? Both use complex equipment, mathematics and scientific knowledge to make things happen. Engineers, however, have to answer a question that scientists don't have to – and that question is: “who cares?”
“I've thought of a better way to do this,” for example, but “who cares?” This is not a rhetorical question where the asker does not expect to hear an answer – it's a real question and the engineer has to find an answer. Often that answer will come from how much money is offered for the solution, and many engineers think that this is the only way to answer it.
I answered this question by thinking about the people who would use the device and how it could help them make their lives and communities better. But why didn't someone else come up with the answer before me? I was never a great student in engineering school and there were thousands of engineers working all around me.
I did, however, have one advantage that most others did not have – my Central education. I graduated in January 1963 with the 219th class (we had two classes a year until the 222nd class). I was not a great student at Central, either, but I followed in the footsteps of my father (148 - 1927) and brother (213 – 1960) and when I asked myself, as many of you may now be asking, “why am I doing this?” I decided that I would learn the answer later.
The important aspect of a Central education, I believe, is its breadth. I've heard Central students ask “why do we need to know this?” when confronted with material outside their intended course of study. Why would a future engineer like myself need to know how to write, or how literature revealed universal truths about people, or Latin, or about history? When I entered the College of Engineering at the University of California at Berkeley I had to take only one course dealing with some of these areas, and an intense regime of courses preparing us to be engineers.
Engineers at Berkeley were generally regarded as somewhat limited in their knowledge of the world - rather ignorant of anything other than engineering. My Central education gave me an advantage over most other engineers. Somehow, as a freshman I was able to write sarcastic, argumentative and yet readable articles for my residential house newspaper and take on editing the paper a year later. Somehow, I was able to absorb lessons from the people around me that were of use in answering that important question - “who cares?”
I credit my Central education for these capabilities, and it's not that I kept remembering facts I had learned in my high school days – the benefit of a broad education manifests in more subtle ways. Upon reflection I believe that Central set me up to continue to learn – gave me metrics against which to compare my experiences, and gave me tools I didn't know I had when I graduated.
What you are experiencing at Central will, I believe, give you similar tools – if you decide take an engaged relationship to the education available here. That is, if you take the question “why am I doing this?” and accept the fact that you may not have the answer – that the outcome will be that you will later find the answer.
It may not seem like it, but this will probably be the most productive and useful time of your life, so I urge you to go for it. You are all in physics class now, but you will not all be destined for technical or scientific careers requiring a knowledge of physics – no matter. Embrace learning without regard to its practicality – make it a game and play, not so much to win, but to do your best. Handle it this way and Central will come through for you in the longer run, as it did for me.
I still get occasional emails from strangers thanking me for what I did in helping shape the form of the personal computer as a tool useful to many people who couldn't care less how it's built. While these expressions are quite gratifying, I'd like to tell them that the credit belongs to Central High, and I'd like for you to prove me right.
Thank you for the gift of your attention.