Feeds

Sinclair ZX81: 30 years old

All hail the pioneer of UK home computing

  • alert
  • submit to reddit

Security for virtualized datacentres

Acorn antiques

The natural rivalry of former colleagues forced Sinclair to push the development of the ZX81 hard. Already conceived as a follow-up that would be cheaper to produce than the ZX80 - it would use fewer chips - but contain dedicated video circuitry to prevent the ZX80's screen flash.

Acorn Atom

The ZX81 was developed by a team led by SoC's chief engineer, Jim Westwood. Its Basic interpreter and OS was written by John Grant and Steve Vickers at Nine Tiles, a company contracted by Sinclair for the ZX80's software. A bigger Rom chip - 8KB to the ZX80's 4KB - allowed Grant and Vickers to extend the new machine's functionality considerably, in particular floating point maths and trigonometry functions.

SoC's Rick Dickinson designed the iconic casing. The look was based on the ZX80, but out went that machine's vacuum-formed cover in favour of superior injection moulding.

Sinclair Research ZX81

How it might have been: Rick Dickinson's early ZX81 design draft
Courtesy: Wikipedia

Once again, SoC used the Z80A CPU and equipped the ZX81 with 1KB of memory. A 16KB Ram Pack add-on would later be offered, and become the source of much annoyance - but hilarity to owners of rival machines - because its poor fit ensured that any movement could cause it to lose electrical contact, crashing the computer.

Sinclair Research ZX81

Sinclair had said the ZX81 would be out in the Spring of 1981, and, pushed hard, the development team managed to do so. The ZX81 was launched on 5 March 1981. Around the same time, Science of Cambridge was renamed Sinclair Research.

New hybrid storage solutions

Next page: Selling the ZX81

More from The Register

next story
Apple iPhone 6: Missing sapphire glass screen FAIL explained
They just cannae do it in time, says analyst
Slap my Imp up: Bullfrog's Dungeon Keeper
Monsters need to earn a living too
Oh noes, fanbois! iPhone 6 Plus shipments 'DELAYED' in the UK
Is EMBIGGENED Apple mobile REALLY that popular?
Apple's big bang: iPhone 6, ANOTHER iPhone 6 Plus and WATCH OUT
Let's >sigh< see what Cupertino has been up to for the past year
The Apple Watch and CROTCH RUBBING. How are they related?
Plus: 'NostrilTime' wristjob vid action
Apple's SNEAKY plan: COPY ANDROID. Hello iPhone 6, Watch
Sizes, prices and all – but not for the wrist-o-puter
Apple Pay is a tidy payday for Apple with 0.15% cut, sources say
Cupertino slurps 15 cents from every $100 purchase
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.