Feeds

Sinclair ZX81: 30 years old

All hail the pioneer of UK home computing

  • alert
  • submit to reddit

Next gen security for virtualised 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.

Secure remote control for conventional and virtual desktops

Next page: Selling the ZX81

More from The Register

next story
So, Apple won't sell cheap kit? Prepare the iOS garden wall WRECKING BALL
It can throw the low cost race if it looks to the cloud
End of buttons? Apple looks to patent animating iPhone sidewalls
Filing suggests handset with display strips
Samsung Gear S: Quick, LAUNCH IT – before Apple straps on iWatch
Full specs for wrist-mounted device here ... but who'll buy it?
Apple promises to lift Curse of the Drained iPhone 5 Battery
Have you tried turning it off and...? Never mind, here's a replacement
Now that's FIRE WIRE: HP recalls 6 MILLION burn-risk laptop cables
Right in the middle of Burning Mains Man week
Apple's iWatch? They cannae do it ... they don't have the POWER
Analyst predicts fanbois will have to wait until next year
Reg man looks through a Glass, darkly: Google's toy ploy or killer tech specs?
Tip: Put the shades on and you'll look less of a spanner
HUGE iPAD? Maybe. HUGE ADVERTS? That's for SURE
Noo! Hand not big enough! Don't look at meee!
AMD unveils 'single purpose' graphics card for PC gamers and NO ONE else
Chip maker claims the Radeon R9 285 is 'best in its class'
prev story

Whitepapers

Gartner critical capabilities for enterprise endpoint backup
Learn why inSync received the highest overall rating from Druva and is the top choice for the mobile workforce.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Rethinking backup and recovery in the modern data center
Combining intelligence, operational analytics, and automation to enable efficient, data-driven IT organizations using the HP ABR approach.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.