Feeds

ARM creators Sophie Wilson and Steve Furber

Part Two: the accidental chip

Gartner critical capabilities for enterprise endpoint backup

Call to ARMs

The first ARM used 25,000 transistors. "It was a really small, simple piece of design," says Furber.

Today one of the most significant features of the ARM family is its low power consumption. But that hadn't been an initial goal, according to Furber. “We designed the ARM for an Acorn desktop product, where power isn't of primary importance. But it had to be cheap. Cheap meant it had to go in a plastic package, plastic packages have a fairly high thermal resistance, so we had to bring it in under 1W.”

The orginal ARM chip at 3µm

The original 3µm ARM chip

The power test tools they were using were unreliable and approximate, but good enough to ensure this rule of thumb power requirement. When the first test chips came back from the lab on the 26 April 1985, Furber plugged one into a development board, and was happy to see it working perfectly first time.

Deeply puzzling, though, was the reading on the multimeter connected in series with the power supply. The needle was at zero: the processor seemed to be consuming no power whatsoever.

As Wilson tells it: “The development board plugged the chip into had a fault: there was no current being sent down the power supply lines at all. The processor was actually running on leakage from the logic circuits. So the low-power big thing that the ARM is most valued for today, the reason that it's on all your mobile phones, was a complete accident."

Wilson had, it turned out, designed a powerful 32-bit processor that consumed no more than a tenth of a Watt.

Steve Furber's ARM SoC Architecture

From the horse's mouth...

“Running on leakage” also happened to be an appropriate description of Acorn outside the lab. To staunch the haemorrhaging finances, Italian computer manufacturer Olivetti stepped in with an initial cash injection in February 1985. By the end of the year, Olivetti had taken a controlling interest, effectively buying the company.

“Olivetti wasn't told about the ARM when they bought Acorn,” Steve Furber remembers. When they found out, he says, “they didn't know what to do with it”. Wilson and Furber did, and were able to push through the ARM’s initial commercial appearance in the ARM Development System, a specialist add-on to BBC Micro costing £4500.

Boost IT visibility and business value

More from The Register

next story
Kate Bush: Don't make me HAVE CONTACT with your iPHONE
Can't face sea of wobbling fondle implements. What happened to lighters, eh?
The agony and ecstasy of SteamOS: WHERE ARE MY GAMES?
And yes it does need a fat HDD (or SSD, it's cool with either)
Apple takes blade to 13-inch MacBook Pro with Retina display
Shaves price, not screen on mid-2014 model
iPhone 6 flip tip slips in Aussie's clip: Apple's 'reversible USB' leaks
New plug not compatible with official Type-C, according to fresh rumors
Steve Jobs had BETTER BALLS than Atari, says Apple mouse designer
Xerox? Pff, not even in the same league as His Jobsiness
TV transport tech, part 1: From server to sofa at the touch of a button
You won't believe how much goes into today's telly tech
Apple analyst: fruity firm set to shift 75 million iPhones
We'll have some of whatever he's having please
Apple to build WORLD'S BIGGEST iStore in Dubai
It's not the size of your shiny-shiny...
NVIDIA claims first 64-bit ARMv8 SoC for Androids
Mile-High 'Denver' Tegra K1 successor said to rival PC performance
prev story

Whitepapers

5 things you didn’t know about cloud backup
IT departments are embracing cloud backup, but there’s a lot you need to know before choosing a service provider. Learn all the critical things you need to know.
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.
Build a business case: developing custom apps
Learn how to maximize the value of custom applications by accelerating and simplifying their development.
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.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.