Some of my Computing Past

BASIC Coding Sheet

BASIC Coding Sheet

The kids of today don’t know how lucky they are. Take computers for instance.

As I progressed through my latter years of secondary school in the late ‘70s & early ‘80s, a new subject was added to the curriculum that really appealed to the nerd in me: Computer Studies.

Before the 1970s, computers were huge, complex and expensive affairs that only resided in military, industrial or university establishments. In short, they were very much out of the reach of the average person. However, by the mid ‘70s all of that changed due to the birth of the Microcomputer. Suddenly, machines were drastically reduced in size, cost and reliability, making them increasingly accessible to the average person on the street. Naturally, being a huge fan of science fiction, I wanted to get my hands on them. So I enrolled on the course. Imagine my surprise when I discovered that the computer we would be using was not located at the school, but in another town around 35 miles away!

We ‘programmed’ this computer by writing out BASIC* programs on coding sheets that were then sent via snail mail to a data centre in Crewe. Upon arrival, the sheets would be typed by hand into the computer. They would then run your program and post back a printout of the output. The whole process took around two weeks from sending off your coding sheet to getting back the results. However, if you had made a mistake, ie incorrectly spelled a command, missed out a comma, declared the wrong variable or, heavens forbid, the person inputting the data made a typo, no attempt would be made to correct it. Instead your program was run until it failed. Of course, on many occasions there would be multiple errors in your program, which you would only discover once previous errors had been ironed out. To cut a long story short, it could literally take months to get a program to run correctly.

Olivetti Terminal - taken from a publicity brochure Circa 1969

Olivetti Terminal – taken from a publicity brochure Circa 1969

After a few terms of this exercise in ‘delayed action insanity’, the school invested in an Olivetti teletype terminal complete with a punch tape reader and an acoustic coupler. Our computing lives were transformed overnight. Now we could enter our programs ‘directly’ into the Crewe computer via the phone line & acoustic coupler/modem and receive the results back in minutes, not months.

Acoustic Coupler. Photo: Peter Edin:

Acoustic Coupler. Photo: Peter Edin:

For those of you not familiar with acoustic couplers, they were large(ish) soundproof boxes which you placed your (land line) telephone’s handset into. Inside the box were two ‘cups’ which you inserted the handset’s mouth and ear pieces into. These ‘cups’ converted electrical signals from the terminal into sound (and vice versa) which were then sent down the phone line to the main computer in Crewe. The same happened at the Crewe end of the connection where the output of the computer was sent back to the terminal in the school. In these days of 21st Century Wi-Fi magic, this practice must sound terribly impractical and archaic, but to us in the late ‘70s, it was cutting edge!

Punch Tape

Punch Tape

As you typed on the terminal, each key depression was captured on Punch Tape. It did this by punching holes into a strip of paper tape in different combinations to represent each key on the terminal’s keyboard. The tape we used was wide enough to accommodate 8 holes (or spaces) per row. Each key had its own unique pattern, so if you typed in the letter A, for instance, the sequence was: Space / Hole / Space / Space / Space / Space / Space / Hole. When the tape was fed back into the reader, the patterns were read and converted back to the keys they represented. If you made a mistake, it was easy to correct by pressing backspace, where the tape would move back one row and all 8 rows were then punched out as holes. A pattern of 8 holes was read by the machine as ‘do nothing’.

'70s ASCII Art. Say Hello to Deborah!

’70s ASCII Art. Say Hello to Deborah!

Somehow, possibly via teacher visits to industry computing centres, we got our hands on rolls of punch tape that did not contain programs, but pictures made out of ASCII characters. The jumbles of seemingly random symbols made no sense until you stood well back to view them. This was our first exposure to computer art. Two I remember well were of a picture of Charles Schulz’s Snoopy with a calendar printed underneath and a ‘naughty’ picture of a nude woman (called Deborah) sitting on a tall stool. The latter tape got copied quite a few times and distributed to all the nerds in the school. I’ll be covering the history of computer art in more detail in a future post.

The Olivetti Terminal was kept in a tiny storeroom tucked away in the school’s maths block. The room was only large enough to accommodate the terminal plus around three people at a time. Due to the lack of space we worked largely unsupervised. Normally the thought of leaving pupils to their own devices would fill a teacher with dread, but since we were all nerds they were not worried. In fact, the only problem they had was getting us out of the room at the end of lessons.

PET Computer Advert - Taken from Wireless World July 1979

PET Computer Advert – Taken from Wireless World July 1979

By 1980, the school truly entered the computer age with the purchase of a Commodore PET (Personal Electronic Transactor). The PET was an amazing machine. Ours was the 2001 version which came with a built in tape deck for reading and storing computer programs, a 6502 processor and a whopping 8K of memory. That’s right. 8 KiloBytes – 40 times less memory than you can find nowadays in the average Tamagotchi toy! 

The PET was a thing of beauty. With its angular shaped box and screen, it looked in my mind how a real computer should. In no time at all our programming skills improved in an exponential curve. Computing in those days was exciting, a new frontier accessible only to nerds. For me, there will never be another time quite like it.

But tell all this to the kids of today and they won’t believe you.


Many thanks to Geoff Macdonald for supplying a few technical details for this posting. Check out his virtual computer museum at:


*BASIC (which stands for Beginner’s All-purpose Symbolic Instruction Code) was a computer language used to program most microcomputers in the 1970s and 1980s.