When I look back on my life, I can see the importance of the Manchester Small Scale Experimental Machine (SSEM, or ‘Baby’). When I was young I did not realise how computers would advance in my lifetime. In fact, when Baby successfully ran its Highest Factor Routine program in 1948, I was only four years old.
As I grew up and went to school I became interested in electronics, building simple one-valve receivers. They did not work very well, but I did manage to sort out the theory and to hear some radio programmes. At least the radios with valves in them were louder and had more stations than crystal sets.
Why, you might ask, did I do things like that? The answer is simple. There were no televisions, and the radio programmes were difficult to hear as the reception was not as good as it is now. There were no digital or FM radios. It was all AM with poor reception and poor frequency response. When not listening to the radio we often used to play in the street, as motor vehicles were very few and far between; things like milk and groceries were usually delivered by horse and cart.
But, I digress. This is about the Baby computer, which will celebrate 70 years since it ran its successful program, proving that a cathode ray tube can be used as a memory device. This simple computer stored 32 words, each of 32 bits on a cathode ray tube. The storage was such that each word could be retrieved at random and therefore it was (and still is) random access memory, or RAM. As the data is stored on a cathode ray tube, the memory is lost when the power is switched off—in other words, the memory is volatile.
Transistors were not discovered until December 1947, and I remember transistor radios making an appearance in about 1955, but they often did not work and were always failing. In the early days of manufacturing transistors, it was trial and error and at the end of a production run, the transistors were selected by testing them individually to determine their characteristics. That is a far cry from today; now, they can be fabricated with great precision and take up very little space. So, as transistors were not much good in radios in 1955, it comes as no surprise that Baby uses radio valves (or vacuum tubes or thermionic valves).
I remember the news on the radio and television (yes, we did have a television, from 1952 onwards!) describing how computers were now changing the world, showing how motor cars were being shaped similarly so that the air resistance was lowered, thereby giving added fuel efficiency. But many of these computers were analogue devices. Digital computers started making an appearance in the news in general in about 1960.
Digital computers were going to make us all redundant and the word ‘automation’ was added to the language.
When it came time to choose a course for university, the headmaster recommended that I study Physics, as this would help me in my electronics aspirations. So, Physics it was, and I was accepted unconditionally by the Victoria University of Manchester to start in October 1962. This became my first taste of city living and, looking back, I found it difficult. I had moved from a town where I knew most people and was now in a city where I knew no one. But! The people in Manchester are very friendly and it did not take me long to realise that a city could be just as welcoming.
Four months into the Physics course and I found that while I could do it, I was not enjoying it. What should I do? Fortunately, a new course was starting in October 1963, the first year of which was Honours Physics. So, I ensured I passed the necessary examinations to start as one of the first seven studing Honours Physics and Electronic Engineering. This was exciting because, at long last, it appeared I would be able to learn more about electronics.
The next year I started attending lectures given by Professor Williams and Professor Kilburn. With the benefit of hindsight, this was a great honour and I could not possibly have had better teachers for the changes that computers were to make in the world. There were, of course, other lecturers besides these, but, looking back, these two had the biggest influence on what happened to me in the rest of my life.
Professor Williams was a quietly spoken man who covered computer memory in great detail in a very relaxed manner. He had no problems in describing how memory worked and the benefits of different types of memory. He did not cover the Williams tube in much detail, and I recall further personal research after Professor Kilburn spoke about the Williams tube and how Professor Williams had invented it.
I still have the text books which I bought to find out the exact method of working. But, I regret to say, I did not have a lot of success, struggling to understand how a cathode ray tube could store memory in a computer. I could understand core store and read only memory, but not memory using a cathode ray tube. However, I did manage to remember (parrot fashion) enough of my notes and the purchased books to achieve a pass in the examination. If only I had known then what I know now!
Attending Professor Kilburn’s first lecture, I was in awe of the man’s knowledge and presentation capability. He did not have any notes, could derive any equation from first principles on a blackboard (in those days, it was blackboard and chalk for lectures) and had an ability to explain it in simple terms. I was impressed, having a secret hope that one day I might be 10% of his standard.
He would be deriving circuits on the board and explaining how they used to use each particular circuit for radar during the war. I had no idea how much work he and Professor Williams did on radar, which was undoubtedly very beneficial to the final outcome. In fact, I recall in my two years being taught by Professor Kilburn that he would often digress into how the team at Manchester provided innovation in computer circuits and techniques that we take for granted today.
I recall that Professor Kilburn explained in great detail how a Miller Integrator worked. I had no idea that this circuit is a key player in the storage and recall of data from a cathode ray tube memory device. 54 years later I realise the full significance of the lectures given by both professors during my undergraduate days.
When I finally graduated I knew a little about electronics circuit design and the basic principles of digital computers. I preferred hardware design and building to programming. The only programming I had done was some simple tasks using (what I now know to be) the Baby instruction set. All seven instructions. This work used a basic Arithmetic and Logic Unit (ALU) to multiply, divide and compare. I recall enjoying doing it and was pleased that I had managed it.
In the ensuing 50 years, I have moved around the world and managed to be a key player in updating railway signalling and control systems to take full advantage of today’s electronics and computer system. What I could never understand is that no matter where I was in the world, I could have a conversation at any level with any person on computers, problems, uses, design and programming. I eventually realised, and this was fully confirmed when I returned to Manchester in 2017, that I had been taught computers from the bottom up. I could identify any part of the family tree and later developments thanks to the excellent training I had been given by Professors Williams and Kilburn.
It is only now that I know I was taught computer circuit design and principles of operation by two of the people who designed and built the world’s first fully electronic computer with random access memory. Walking into the Manchester Museum of Science and Industry in April 2017 and finding the Baby computer, it was like going back to 1959 when I used to build radios and hi fi equipment using exactly the same electronics components as used to construct Baby.
I owe a great ‘thank you’ to Manchester, the University of Manchester and in particular Professors Williams and Kilburn for giving me a good foundation together with all the necessary building blocks to see computers and systems develop from the simple Baby with a memory of 128 bytes, to my iPhone with 8 gigabytes. It took the development of integrated circuits and microelectronics to achieve this and it should be noted that the dynamic RAM in today’s computer chips use the same basic means of storing data as invented by Professor Freddie Williams in 1946. To have invented that at any time is no mean achievement and for the team to have worked to produce the world’s first all-electronic Turing compliant machine is truly remarkable.