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A Personal History of Systems and Computers: Part 2


Dan can be contacted at dwohlbruck@aol.com.

In January 1966, I went to work for the Bell Telephone Company of Pennsylvania in Philadelphia and I began to learn IBM 1401 Autocoder. I described much of what I learned about Autocoder in the Part 1 of this series. After three weeks, along with a few of my classmates, I was selected to learn the IBM 360 Basic Assembler Language (BAL). So, on another Monday morning, I reported to the IBM Education Center at Suburban Station in Philadelphia to begin my study.

There were six or seven of us from the previous class that had been chosen to learn BAL and when we arrived at the Education Center, we were directed to our new classroom. The room had four rows of tables, enough chairs for the students, but no lectern for an instructor. Promptly at 9:00, two gentlemen, one from IBM and one from Bell Tell, arrived and explained that we were to be part of an experiment called "programmed instruction." We would be given paper-bound text books, Assembler Language coding pads, and pencils, but otherwise left on our own to learn a new generation of computer architecture and the language used to program it. Every 90 minutes an IBM expert would join us and ask us if we had questions. After a brief discussion with the expert, we would take a break.

Over the years, as I've thought about this experience, the only explanation that rings true is that the Bell Telephone company, faced with the need to train more than a hundred programmers in Assembler Language, made a deal with IBM to try to reduce their education costs. We, however, were only told that programmed instruction was the wave of the future and that it would soon replace instructor-led training. The fact that any of us learned BAL was due to the determination of my classmates and not the craziness of throwing half-a-dozen guys in an empty room with some books and telling them not to come out until they knew the Basic Assembler.

My strong-minded fellow students were male. We were Bell Telephone company employees who had taken the programmer aptitude test, then transferred to the computer department. Most of the students were from Philadelphia or the suburbs. In our original class of 15, only two other students were from out-of-town. I was from Harrisburg, another from Allentown, and the third, I believe, from Scranton. All of my classmates had installed or repaired telephones and they were happy to be in a warm room in February instead of a cold truck. So, despite the difficulty, we set out to stay warm and learn BAL.

The IBM 360 was made from integrated circuits, unlike the 1401's transistors. And, unlike the 1401 Autocoder, the 360's assembler language was based on the binary number system. Our programmed instruction text reported, "The binary system works under the exact same principles as the decimal system, only it operates in base 2 rather than base 10." No single sentence would cause me more problems. The binary system wasn't the same as anything that I had learned before, it was different.

We read that, as its name suggested, the binary number system used only two digits, 0 and 1. I was all right until the number 2. The number 10 (base 2) was the same as the number 2 (base 10), we were told. Our book showed long strings of zeros and ones, then an equal sign followed by a tidy two or three digit decimal number. Our book demonstrated how we could add and subtract these long strings of digits should we ever find the need to do so. I was confused.

When the expert joined us, I asked for some explanation of the binary system. He smiled, seemed nervous, and confided that we would probably never need to know about binary numbers. The expert advised us that rather than 1s and 0s, we should really concentrate on hexadecimal. Hearing no other questions, he left the room. He was the expert and he was right.

The hexadecimal system (called hex) substitutes a single character for four binary digits. Thus, once again, 2 was 2. Or, more accurately, 0010 was 2. It did get a little messy when you got past 9 because A was 10, B was 11, and so on until F being 15, but I could handle hex numbers. They just looked better to me. And, with that, we finished our first day of programmed instruction.


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