Sinclair ZX81

Sinclair ZX81 old school computing

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It’s 1981, and I’m an 10 year old boy fascinated with the emerging world of personal computers.  My dad would bring home a Commodore Pet machine from work, the same shape and size as a small car, over the Christmas period. I would spend hours playing Snake (yes, years before Nokia got in on the act) and various dungeon based games punctuated by, well punctuation, as the character “sprites” on screen were all “$”s and “&”s.

Sinclair ZX81
Sinclair ZX81
At the weekend I would lurk around the local Tandy store (UK equivalent of Radio Shack, now long gone) and marvel at machines like the TRS-80 and TI994A, looking through the software catalogues and imaging how good the colour screens on these machines would be, and how advanced the graphics looked.

From here I would head off to John Menzies (another long forgotten chain of stores) and see what computer magazines were out.  It was here I found the mythical Sinclair ZX81, on sales amongst the typewriters and led calculators.  This was a chance to own my first proper computer, and for less that £80.  My 11th birthday came, and so did the little black box with my new ZX81 inside.  After unpacking the hefty manual, and plugging in to my black and white TV (tuned to channel 35) I was good to go.  

So what next?  Well, you were presented with a little blinking cursor, and that’s it.  No hard drive, no windows, no mouse, no idea what day it is, who you are, or what it was doing yesterday.  Every day was day 1 for a ZX81, and you had to tell it what to do, from scratch, every time.

So I read the manual. And I started programming, got my name printed on the screen, tried some FOR..NEXT loops, played with input and output, and then when I got to line 15 of my programme – “OUT OF MEMORY”.  Yes I’d reached the 1k RAM threshold of the standard machine.  Yes 1K – that’s 1,000 bytes.  I’ve just saved this document in Word and so far it’s 12K.  My toaster has more memory.  Dad is promptly dispatched to Menzies for a 16K RAM pack and I can complete my program, albeit very gingerly, because whenever you bash the plastic membrane keyboard too hard the RAM pack wobbles and you lose all the code.

Master program completed (a question and answer session that tells a “knock-knock” joke), I want to save my magnum opus.  Enter the cassette recorder, a new C90 tape, press play and record and type “SAVE”.  A wobbly screen and a few seconds of squawking later, and the programme is saved for eternity – or until you tape over it with the Top 40 on Sunday.

Looking for some hardcore gaming action, I would peruse the back pages of the computer magazines, and send off a cheque or a postal order for the latest game – no online reviews, no screen shots, just the programmers often exaggerated description of the gaming delights on offer.  Eventually the tape would arrive and you would spend several hours trying to get the tone of the recorder right in order to load the game correctly.  It was pot luck if the game was any good or not, personal highlights for me were John Ritmans Namtir Raiders, and my all time favourite 3D Monster Maze.  What these guys could do with a black and white low-res screen was amazing.  Much of the rest were variations on letters chasing other letters around the screen in complete silence.  

Time passed by, and I moved on to the Spectrum, what with it’s “real” rubber keyboard and flashy full colour graphics, and the ZX81 became redundant.  I can’t however forget how it introduced me to the world of computing, and that I knew this was the start of something big.

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2 thoughts on “Sinclair ZX81 old school computing”

  1. Was just talking about the Raspberry Pi connecting to the TV & commenting on how it would be more realistic if you then had to tune it in to channel 35. No idea how I remember that channel lol! ZX81 was my first computer too. In fact I still have it, although I’ve no idea if it still works… and here it is :-)

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