Awww my first computer …

March 11th, 2011 by Kat Kingsley-Hughes

The BBC published an article today about the Sinclair ZX81 which really tugged on my heartstrings. I still have my ZX81 (her name is Henrietta) and she still works … after a fashion.

Henrietta still has the 16k RAM pack which upraded her from 1k to 16. It plugged into the back with rather a dodgy connection so you had to be mega careful to never jog the RAM pack or the ZX81 would crash – losing all your work.  We actually took the RAM pack to bits a few years back to show the kids the huge chips inside. They were remarkable for their time but put one next to an 8GB microSD card and well let’s just say it made me feel a bit old fashioned. It’s hard for kids to grasp just why a 1 kb chip needed to be at least 250 times the size of an 8gb chip (that has over 8000 times the capacity).


The membrane keyboard (that my dad thought wouldn’t last very long) still works just fine thirty years later and is also just as frustrating to type on as it ever was.  Just to think I would type in programs that were hundreds of lines long – being careful never to jog the RAM pack – and then painstakingly debug them for hours on end. There was no internal storage or floppy disk – that wouldn’t come along until the later models of the ZX Spectrum  – so we had to manage with recording our work on cassette tapes.  This meant plugging in a standard household tape recorder into the microphone socket on the ZX81 and crossing your fingers.  If you were lucky you would start your tape recorder recording, set the ZX81 to save and no one would come in the room, jog the RAM pack or sneeze until your work was safely saved.  Of course there was no way to know if the recording was a success without testing it. And that meant resetting your ZX81 – and risk losing all your work if the tape recording had screwed up.  Faced with that decision I usually made TWO tape recordings of my programs.  Sadly though even two recordings didn’t work and I lost a lot of work – and time – that I never bothered to type out again.

Loading a program was as fraught as saving.  Very often a program would fail to load correctly due to a faulty tape, excessive hiss on the recording – or the squawks of my budgie. He seemed so adept at interrupting the whole process that I was convinced he actually understood what was going on.  My programming time quickly became night-time for him as I would cover him up with a curtain just to shut him up.

The favorite programs we would write were games. Simple things that involved moving a dot about. Another was drawing pictures. Very often this involved drawing vectors and peeking and poking, none of which really means very much to me now. I only remember that I did it – and the proud sense of satisfaction that came from it.

The ZX81 was quickly replaced in my life by the Acorn BBC computer which was a way superior experience in so many ways. It plugged into a color VDU monitor for a start (rather than a portable black and white telly like the ZX81 did).  It also had twin floppy drives in an external drive (which was great for copying and sharing files and programs – all ones that we had written of course, and if you believe that you will believe anything).  And with the BBC was an easy bodge to put a zif socket on the outside so before long we were able to write EPROM chips with programs on. When we wanted to wipe them we simply left them in the sun.

And it was always sunny in those days.  Actually thinking back about it the only time I opened the curtains was to wipe a chip…

This entry was posted on Friday, March 11th, 2011 at 10:23 am and is filed under Flotsam, Hardware. Both comments and pings are currently closed.

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