Technology | Nostalgia | 1980s

Remembering the Sinclair ZX81

Facts, opinions, and personal memories of what was nearly my first home computer

This is an updated version of an article I wrote a few years ago for some of my now-defunct blogs.

I’ve only had this Sinclair ZX81 since 2009, and it’s not in pristine condition. But it means a lot to me as you’ll discover. Author’s photo

The Early 1980s

In 1981, Sinclair Research released a low-cost home computer called the ZX81. It proved to be very popular in the UK.

It was designed as a cheaper and improved version of its predecessor, the ZX80.

Like the earlier model, the ZX81 was based on the Z80 microprocessor and available ready-made or in kit form. I remember seeing adverts for it in electronics hobby magazines at the time.

An advert for the ZX81 in the November 1981 edition of Everyday Electronics. Author’s photo

Limited Specification

To meet the low price point, the ZX81 was not exactly bristling with features. It had no colour or sound, a membrane keyboard, and a tiny 1 KB RAM.

Its Z80 microprocessor was clocked at 3.25 MHz, and it had an 8 KB ROM, which included the BASIC programming language.

The ZX81 had two modes: FAST and SLOW. In FAST mode, it ran at full speed, but there was a catch: the video output was only produced if the machine was waiting for user input, resulting in a flickery display. SLOW mode gave a steady video output at the expense of speed.

I Wanted One

Despite its limitations, I still longed to get my hands on a ZX81. Having used the Apple II and BBC Micro at school, I was keen to experiment with programming at home, having reached the limits of my programmable calculator.

Nearly My First Computer

I remember the excitement when my high school computer studies teacher told the class she was selling her ZX81. Even better, my parents seemed willing to buy it for me.

When I plucked up the courage to speak to the teacher, I was gutted to discover a classmate had already bought it, so I missed out on it being my first computer.