Inside ARM: The British success story taking the chip world by storm

...smartphone and laptop chips that can run all day without draining batteries, while the growth of cloud services is pushing datacentre operators to seek new ways to reduce the electricity bills that swallow so much of their budgets.

As ARM's ambitions expand, the company finds itself encroaching on territory dominated by Intel, including the Windows PC and server market. This year saw Microsoft Windows and Office running on an ARM-based system for the first time, with the release of Microsoft Surface RT tablet.

And within the next couple of years ARM will enter the server space in earnest, with the first AMD Opteron servers based on 64-bit ARM designs due out in 2014.

Despite the server market being uncharted territory for ARM, Muller believes the time is right for the company to make its move.

The rise of people accessing software and services over the internet plays to the low-power strengths of ARM's Risc architecture, says Muller. Running these services doesn't demand chips with a surfeit of raw processing power, but rather a datacentre where processing power can be scaled rapidly to meet peaks in demand.

Of course Intel x86-based chips can scale, but if a task doesn't rely on individual processor performance, then the lower power consumption of the ARM architecture could start to look attractive to cloud service providers wanting to reduce energy bills. HP and ARM-backed server chip start-up Calxeda estimates it can produce a server at about 35 percent of the cost and 10 percent of the energy consumption of a conventional server.

"In a web-based service deployment it's about scalability," says Muller. "That opens up the prospect of 'Why don't you build those server farms out of more power-efficient components?'"

ARM doesn't expect to become a major player in the server market overnight, nor does it initially envisage itself challenging Intel in areas served by its high-performance Xeon processors. But by targeting web services ARM is going after business with some of the biggest names in tech – Facebook, Google and Amazon – not to mention the rapidly growing web services market. Facebook is already running large-scale tests using ARM and other chipsets.

"Initially we will be targeting those scale-out web workloads. The bit we're going after is the area where there's lots of volume and growth," said Muller.

In targeting the web services market, ARM is acknowledging the performance limits of its chips, which toe-to-toe can't match the processing power of the likes of Intel's Xeon processors. Sergis Mushell, principal research analyst with Gartner's technology and service provider research group, thinks ARM's server chips will be suited to what he calls the microserver market — servers used to perform tasks like web hosting and streaming video, which are I/O intensive but require low levels of processing. The microserver market accounts for about 10 to 15 percent of the nine to 10 million servers sold annually, he said.

However, incompatibility with legacy software will limit the market for ARM-based servers within large enterprise and government, Mushell says.

"You still have governments seeking software engineers for punch cards. Things linger on in corporations and governments for a long time. You do not rip and replace things just because they're more efficient."

"Things linger on in corporations and governments for a long time. You do not rip and replace things just because they're more efficient" — Sergis Mushell, Gartner

Mushell sees more of a market for ARM servers among large web companies like Google and Facebook but said there would still be the burden of managing x86 servers alongside ARM servers, and retaining the skills and parts necessary to run both.

The convenience of having a general-purpose, all be it more power hungry, Intel x86 server, which the company already has the skills and equipment to maintain shouldn't be underestimated, he says.

"X86 architecture, while it's not the most efficient architecture in the world, it's like the one wrench you can have in your toolbox that can do everything. Most people don't use a steak knife, a bread knife, a butter knife — they just want a good sharp knife in the kitchen," he said.

"It is not to say that ARM will not find application and usages. I think the opportunities are there for ARM to compete very aggressively with Intel. It is to say the world will not change over in a heartbeat."

Datacentre market

Alongside servers, the datacentre market also provides an opportunity for ARM and its partners to sell chips for storage and networking. ARM has already made inroads into networking, persuading semiconductor manufacturers that sell into the networking market — the likes of Freescale and LSI — to switch to ARM-based chips from competitors.

"ARM will find a home within the datacentre no doubt. The question is where the server is going to be," says Mushell.

ARM's Muller sees its contesting of the server market as a case of 'slow and steady wins the race'.

"We started work on servers four to five years ago. People thought 'Why? What's the point? You're wasting your time'. Product is starting to appear now. Give us another year or two and it will start to take off."

Breaking into the server market won't be easy for ARM. The incumbents have an advantage in that customers are already set up to use existing x86 architectures. But for the likes of web services companies, where datacentre costs swallow up large proportions of operating budgets, Muller believes the trials of transition will be offset by the lower running costs.

"If you can say 'I can make your datacentres 10, 20, 30 percent more power efficient, that really matters to their running costs. Therefore it's worth them putting in investment to go through whatever pain there is," he said.

How ARM designs a chip

The process of designing a chip begins with ARM consulting its customer base on what capabilities and features – the likes of media performance extensions or hardware-level security support — they want to see in future chips.

Using the list as a guide, ARM then defines and locks down the instructions that the chip will be capable of executing. The next step is defining the processor pipeline, the various stages of operation that a processor goes through when executing instructions, which is constrained by factors like the available power and the silicon die area.

Electronic design automation tools then take these higher-level processor designs and translate them into the required arrangement of logic gates within the processor core. Designers then go in and refine the arrangement of logic gates to perfect the design.

Third parties will then license that design, which in general will be a circuit description that sets out how data flows between registers on the chip, and incorporate it into designs for their own chips.

The Intel fightback

The perception might be that, as ARN encroaches into what has been x86 territory, the big boys are just sitting still while it attempts to eat their lunch. But it's by no means a one-way street.

Intel is mounting its own counteroffensive into ARM's home territory of mobile...