PJCNET

In 1980 my parents decided to buy me what is now known officially as the very first mass produced home computer which was the Sinclair ZX80 for Christmas 1980 (Also see http://www.nationmaster.com/encyclopedia/Sinclair-ZX80). In those days people very rarely had computers at home and even in most offices, you’d only see typewriters and files, so the thought of owning a computer then was very exciting indeed.

For people who don’t remember the Sinclair ZX80, it was the predecessor to the much better known, more popular and improved Sinclair ZX81 which was released a year later in 1981 for an even cheaper price. The ZX80 & even more so the ZX81, which appeared in many reputable high street shops, kicked off the 1st ever home computer craze, neither of these early personal computers had colour or sound. About a year after the ZX81 came the Sinclair Spectrum in 1982 which boasted 16K or 48K of memory with colour and sound. All 3 computers were pioneered by Clive Sinclair, now known as Sir Clive Sinclair who was a great British inventor, his various inventions also included the first ever pocket calculator.

What was amazing about the Sinclair ZX80 was it’s affordable price. Until then computer prices were way above what the average person could afford, but the Sinclair ZX80 cost just under £100 ready to use and just under £80 in kit form, but making it from kit form was horrendous and involved literally soldering 21 chips onto the main board along with various other electronic components. The price is what made the Sinclair ZX80 go down in history as the first ever successful home computer, although some people disagree as much more expensive personal computers like the TRS-80 and the Apple II were released in 1977 followed by many other early personal computers before the Sinclair ZX80.

I remember my parents ordering and paying by cheque for the ready made Sinclair ZX80 at least 3 months before Christmas 1980 when I was only 10 years old going on 11 year old. The Sinclair ZX80 avert clearly said, “allow 28 days for delivery”, but instead of receiving the computer after 28 days we received a post card from Sinclair Research in Cambridge apologising for unavoidable delivery delays, asking us to please wait another 28 days. Luckily the ZX80 finally arrived just in time for Christmas. Unknown to us, Clive Sinclair only made a prototype of the ZX80 and advertised it everywhere before he had the money to mass produce the product.

The ZX80 had only 1K of memory (1 Kilobyte of RAM) and had a tiny 4K ROM with a Zilog Z80 processor (CPU) which ran at a speed of 3.25Mhz which was surprisingly reasonable speed back in 1980, especially when one considers that the Commodore 64 had a 6510 processor that only ran at close to 1Mhz when it was released later in 1982. The more modern and much more advanced Commodore 64 however made up for it’s lack of main processing power by having various custom chips to do a lot of the work, while the ZX80’s main processor had to do absolutely everything. It came with a very cut down version of the “BASIC” programming language that was so cut down it didn’t even have many standard commands like, for instance “FOR” & “NEXT”. It could only cope with very limited integer arithmetic too, where “BASIC” variables could only hold from -32767 to 32768. It had a dreadful membrane keyboard built into the case that was very weak and non-durable. One had to press various keys together to bring up all “BASIC” commands, one couldn’t simply just type in commands like “PRINT” or “GOTO” one letter at a time, but instead had to press the correct key combination which was a nightmare to get used to and learn. When there was an error running your “BASIC” program, instead of displaying an error, E.g. “Syntax Error in 10″, it would just display an error number. When you ran out of memory typing in a program, you wouldn’t even get an error, the cursor would simply hang until you pressed the delete key to free up memory and you couldn’t type much with just 1K RAM available. There was no colour or sound and the modulated output to the TV was very poor quality with massive blocky characters. Because the main Z80 processor did absolutely everything including controlling the output to the screen, it struggled to multitask at all. Because of this whenever the ZX80 was processing something, the screen would literally flicker off completely. So say for example the ZX80 was running a program to count from 1 to 100, displaying each number on the screen, the screen would just go blank until the program had reached 100. The only command that could pause processing to display the screen within a program was the “Input” statement which would wait for the user to type something to continue.

You could save your precious ZX80 programs to a standard cassette recorder if you were very lucky, you’d often have to experiment with the volume control or even mess with the head alignment to get it to actually work for hours. Another awful feature of the ZX80 was how terribly unstable it was, just the slightest knock, pressing too hard on the keypad could crash the computer completely losing any work. Even if you were very careful, it would often overheat and crash intermittently without any warning. My father actually cut an extra hole in the case to help keep it cool and more stable.

After the ZX80 had been released for a while Sinclair released various RAM upgrades, expanding the computer up to a maximum of 16K of memory, which in 1980 was actually plenty. Sinclair also released a small dot matrix printer that printed onto rolled paper.

The ZX80 holds more than just retro status. It’s a real shame my parents eventually sold my ZX80 when we upgraded to the ZX81. A working ZX80 is a collectors item and some people are willing to pay hundreds of pounds to get hold of one, so why not check your loft or attic.

Please click to share this article!