For me it would be being introduced to an ICL 4130 (formerly an Elliot Computing 4130) mainframe and the use of punch card decks. I was instructed on how to program the computer using the computer language Algol-60 and I had to write the code on sheets that were then punched by punch card operators. Somewhere, I have a booklet which describes the machine … somewhere!
Anyway, by the time I’d got started on my computing life the 4130 was getting a bit long in the tooth and the form for Universities in those days (remember everything was centrally funded by the Universities Grant and Research Grant Committees of the Education Department then) was to get a visit from the Computer Board – a group of the wise and worldly (it must have been, I went on to serve on its successor body much later on – the Joint Information Systems Committee) who would adjudicate whether an institution needed a new computer or, if it was between its regular visits, whether the Computer Centre needed new peripherals such as disk drives, printers or plotters. As a research student (at UCW Aberystwyth) I, along with my other researchers were fully prepped to be able to say the right thing just in case one of these visiting folk asked a question. What fun! The preparation must have paid off because we got a new machine.
The ICL 4130 was replaced by an ICL 1900 series machine running George 3 – a proper operating system [I think a second machine was purchased later on and they were linked so that one could handle batch punch card jobs and the other handled teletype terminals and possibly output]. Of course this was the time when Computer Operators were needed and they ran jobs (including back-ups) overnight and had to be in attendance to change magnetic tapes, and handle printed output – a lot of which was created by me!
I was teaching myself multi-variate statistics, mainly based on linear and multiple regression models, but also principal components and factor analysis and using standard programs which I modified in part to my research subject because I needed mapped output, on a line-printer! The main program I worked with however was written (in Fortran IV) by David Wishart from St Andrews for Cluster Analysis, so I learnt to program in Fortran and this soon replaced Algol-60 as my preferred programming language. This program and its adaptation to spatial analysis (in which I followed the work of a fellow researcher called Stan Openshaw who was using the technique in human geography to group together similar grid cells from maps) was to take up a huge part of the next 10 years of my life as I worked hard to avoid actually going out to do any field work on my research topic “Contemporary Erosion in mid-Wales”. Most of my jobs were by now being run by remote job entry at the Manchester Regional Computing Centre as the size of my data set was too large to run in the UCW Aberystwyth Computer Centre.
It was an exciting time to be a geographer and books and monographs were being published on quantitative geography amongst which were ones in the Institute of British Geographers CATMOG series, still in my possession, by a certain John Silk. A lovely coincidence that brings John and myself together and allows us to reminisce on the early 1970’s and “the quantitative revolution” as it was called by some!
Through the 1970’s I returned every summer holiday to Aber, and camped at the top of Penglais Hill to get time on the mainframe. In between these visits I would sit at a teletype at Doncaster College of Education, where I was now a Lecturer in Physical Geography, and submit jobs to the IBM 360 mainframe at what was then Sheffield Polytechnic. 
It had to be said that by 1978-9 my main interest (apart from the family that was now arriving on the scene) was in computing, not geography, and so when a friend asked me to put my knowledge to work in programming some engineering design problems, I accepted the challenge, set up my own consultancy (with my HoD’s approval) and started programming an Olivetti P6060 desktop computer using Basic. Having it at home to do the work allowed my eldest daughter (44 yesterday) to have a go at programming …
So now the link to geography had begun to be broken. This was severed by Shirley Williams decision in 1978 to close the Teacher Training part of the College where I worked. I bravely, one of my colleagues thought foolishly given that we had by now three young children, decided to opt for voluntary redundancy on the basis of being given a year’s fully-paid retraining. I went to Bradford University and did a one-year MSc in Computer Science giving me letters after my name to go with my 10+ years programming experience. Here I was introduced to the DEC PDP-11/60 mini-computer – a lovely machine running Unix, which was a lovely operating system which I continue to use in it’s Linux incarnation, to this day. I wrote my thesis on building a disk operating system (Modus) for a PDP-8 using a high-level structured programming language (Wirth’s Modula) on the PDP-11. I could now program in Algol-60, Basic, Fortran iV, Fortran 66, Cobol, PDP Assembler, Pascal and Modula.
It was the latter language (the first concurrent programming language and the precursor of first Modula-2 and then Ada) that enabled me to get a job as a Systems Programmer / Computer Lecturer at South Glamorgan Institute of HE at Llandaff. I was returning to Cardiff and HE. Not a very bold move and “only for 4 years max” (which is what I said to Jenny). 
That was not to be! At SGIHE/CIHE/UWIC I oversaw the introduction of a mini-computer service based initially on a Prime 550, then Prime 750 and so on, initially writing the systems programs for its operating system – Primos in Fortran, PL/P and SP/L, and then becoming Head of the Computer Centre where I dabbled in producing the first website for the institute, which has since been a continuing interest for me.
Here are a few pictures of the Computer Centre at UWIC taken before I left for UWCM at UHW (The Heath) …
The Operator’s Consoles for each system are on the left, the tape rack for the day’s tape back-ups are in the background, a terminal room with micro-computers was alongside the Computer Centre …
The original Line printer (orange) was till in service, the Prime 750 is in the background …
I’d become a manager, and the rest is another story, which I’ll record another day!
At home we’d purchased one of the first BBC-B Computers – the first of a long series of domestic computers which again is another story, which I’ll record another day!
David Harrison, June 2020
