What Does ARM Stand For In Smartphones And Computers?

If you've been paying attention to smartphones and computers, you've probably heard people refer to ARM processors with increasing frequency. First developed by a small team of researchers in the early 1980s, ARM was designed to revolutionize traditional computer processors by making them more efficient. Although they're most closely associated with mobile devices, these days, ARM is stretching out to encompass more of our computing landscape than ever before. What's most interesting, is that these now hugely popular and important processors once had humble beginnings.

ARM is actually an acronym within an acronym. It stands for Advanced RISC Machine and refers to a type of central processing unit (CPU) that relies on a reduced instruction set computing (RISC) architecture. Think of computer instruction sets as guidebooks that tell a processor what to do, much like someone who runs a shipping warehouse will be trained to manage the workfloor. RISC processors carry out processing tasks using a much smaller set of machine language instructions than competing architectures like x86. ARM is in fact a specific variety of the RISC instruction set that is proprietarily developed by the company Arm Limited. More on this organization later.

As ARM processors are more efficient than other kinds, with a smaller physical footprint, they have traditionally been perfect for pocket-sized devices. However, over the past five years, the industry has seen a massive push to use ARM chips in laptops and even desktop computers. So, how did we get here? The story of ARM begins in a converted barn north of London, and it ends in the palm of your hand.

The story behind ARM, like that of many world-changing inventions, is one of necessity. In the early 1980s, Acorn Computers was looking for chips that could power the BBC Microcomputer, a computer it had been contracted by the British Broadcasting Corporation to make for the purpose of encouraging computer literacy. To this end, a research team comprised of computer scientists Steve Furber and Sophie Wilson were stationed in a converted barn in Cambridge and tasked with designing a more efficient, powerful, and affordable processor architecture.

Hermann Hauser, the co-founder of Acorn, gave Furber and Wilson research papers describing a RISC CPU. Based on these concepts, Wilson wrote a minimalist RISC instruction set containing only 45 instructions. The instruction set might have been small, but the implications were massive. The ARM V1, the first chip of its kind when it was first tested in 1985, had only 27,000 transistors compared to the most advanced competing chip that had 134,000.

However, it would take a while for ARM chips to make the impact we see today. Acorn was thrilled when Apple came calling to use ARM in a new handheld computer. Unfortunately, that device was the Apple Newton, one of the most infamous commercial flops in the history of the Cupertino company. Even so, Apple remained invested in the technology, and in 1990 Arm Limited was founded as a joint venture between Acorn, Apple, and semiconductor producer VLSI. It worked by licensing chip architectures  — essentially, the blueprints for processors  — to manufacturers who could then use them to produce purpose-built ARM chips. That business model turned out to be a stroke of genius, and it was only a matter of time before ARM took the world by storm.

The list of companies who use ARM designs is impressive, including Apple, Amazon, Google, Intel, Microsoft, Nvidia, and Samsung. What Furber and Wilson created in a Cambridge barn is now at the core of our everyday tech.

The dawn of the smartphone age was a major catalyst for that success. Apple put ARM into its line of iPod music players during the early 2000s, and Nintendo tapped it for the Game Boy Advance, but it wasn't until Steve Jobs debuted the iPhone in 2007 that demand for ARM skyrocketed. 

Companies across the tech industry pivoted to meet the future Apple had unleashed. Samsung, which supplied ARM chips for the original iPhone, would soon become its largest rival. Google hard-pivoted its incubated Android project into a smartphone OS. And all the devices these companies released would need ARM chips of their own.

Nevertheless, traditional computers never eschewed x86 architecture because they needed raw power more than they needed efficiency or compact designs. By contrast, smartphones had to be pocketable while retaining good battery life, great performance, and running a variety of applications.

In 2020, Apple once again kicked off the next ARM race by releasing the M1 chip, a complete SoC on an ARM processor. Its power and efficiency far surpassed expectations in the industry, but Apple had been iterating on its in-house, ARM-based designs since the A4 chip that shipped in the first iPad. However, that head start is beginning to wear off. The first batch of ARM-powered Windows PCs shipped in 2024 as part of Microsoft's Copilot Plus PC banner, powered by the Qualcomm Snapdragon X Elite.