Feature

Old computers: the Epson HX-20

We have received reader feedback on old computer kit. Here are more fond memories...

Epson HX-20

Information services manager, Peter Lancashire, says, "The Epson HX-20 was a laptop, with a decent keyboard, a tiny four-line by 20 character LCD screen, a cassette tape for data storage and a printer. It was packed into a trendy silver casing. Battery life would shame a laptop.

"I encountered it when working for the Ministry of Agriculture in the mid-1980s. Some colleagues managed to ruggedise it with clingfilm - the keyboard did often need replacing.

"The HX-20 was programmed in what looked like MS-Basic. We wrote our own programs for collecting data and statistical analysis.The problem was getting data out of the HX-20 and into the Prime mini-computer system.

"My contribution was writing a small terminal and file transfer program to keep up with the 4800 baud serial port. I did this by running the x-on/x-off flow control loop in the top two lines of the program. This was necessary for enough speed from the brain-dead MS-Basic, which searched for jump destinations linearly from the top of the program.

"I have fond memories of the HX-20. Its tapes were portable. The cases clipped together neatly. How many laptops come with a printer now?"

Technical support manager, Rupert Moss-Eccardt, comments, "It was nice to see the HX-20. It was a shame not to mention the PX-8. HMV had one in every store. Hotels still have them for telephone logging."

Systems administrator Nick, says, "I've compiled daft attempts of pushing hardware to its limit."

  • One-bit audio sampling using a standard ZX81 + 16K Ram pack. Not hi-fi, but it was possible to record a few seconds of semi-recognisable noise in 16K.

  • Time bombs and booby traps in Boots and Dixons. I was a child who wrote programs on shop machines. The Oric 64 was loud. Write a little program that made it look as if it had rebooted and when a customer pressed a key, there were explosions followed by scrolling messages of "User Error!".

  • An "apparently" impossible interrupt driven clock on a ZX81. My physics tutor told me it was impossible because of hardware architecture. I proved him wrong.

  • High resolution graphics on as standard ZX81 + 16K Ram pack. We called it high resolution, a massive 256 x 192 pixels.

  • Rewired and attached an old teletype terminal to my ZX81. The membrane keyboard got worn out.

  • Arbitrary rotate of bitmaps on an original IBM PC with Hercules graphics. It took 15 minutes to rotate a 16 x 16 monochrome bitmap through x degrees, hardly impressive graphics handling.

  • Play tunes on the disc drive of an Act Sirius. The Sirius used linear velocity drives, as the head got closer to the edge. It speeded up and the motor hum increased frequency.

    "I should have got out more."


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    This was first published in December 2000

     

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