Fond memories of ZX81

A systems administrarit has fond memories of using now obsolete computer hardware, such as ZX81

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Data centre

A systems administrarit has fond memories of using now obsolete computer hardware, such as ZX81

In response to our request for tales of old hardware and software, a systems administrator called Nick provides us with tales of his formative attempts at pushing hardware to its limit. He says he would like to retain some anonymity as he admits that he probably should have got out more,

1 bit audio sampling using a ZX81 + 16Kbyte ram

"Not exactly hi-fi, but it was possible to record a few seconds of semi-recognisable noise in 16Kbytes. I have still got a recording somewhere."

Time bombs and booby traps in Boots and Dixons

"I'm afraid, I was one of those little bastards that used to entertain myself by writing short programs on machines in shops. For example, the Oric 64 was extremely loud. Write a little program that made it look as if it had just been rebooted and when an innocent, but curious, customer pressed a key, wham! continual explosions accompanied by endless scrolling messages of 'USER ERROR!'."

An "impossible" interrupt driven clock on a ZX81

"My physics tutor told me it was impossible because of the peculiar hardware architecture, so I proved him wrong."

Arbitrary rotate of bitmaps on an original IBM PC with Hercules graphics

"It took about 15 minutes to rotate a 16 x 16 monochrome bitmap through x degrees - hardly impressive graphics handling."

High-resolution graphics on a ZX81 + 16Kbyte ram

"Well, we called it high-res then - a massive 256 x 192 pixels."

Attaching an old teletype terminal to my ZX81

"The poor old membrane keyboard got worn out."

Playing tunes on the disc drive of an ACT Sirius

"The Sirius used constant linear velocity disc drives, as the head got closer to the outside edge of the disc, it used to speed up and the motor hum increased in frequency. Sad!"

IT capers from the past

Did you ever push the boundaries of early technology? Or maybe its limitations just drove you up the wall? Let us know at

This was first published in March 2001



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