ARM processors came in an age where the world was already enamored with the works of Atari, 3COM, Oracle, and Seagate. 

Nobody could begin to imagine what changes this ARM processor was going to bring to the tech industry in the later years. The early struggles of ARM processors tell an entirely different tale than today. Today, ARM processors are found in the most energy-efficient mini PC and other PCs as well as other computing devices. We see windows on ARM and Mac OS on ARM, but the trip down the memory lane is going to tell a very different and yet inspiring story about the evolution of ARM processors.

Beginning of ARM 

In 1979, a group comprising Chris Curry, Herman Hauser, and students from the University of Cambridge set out to make something for educational purposes. The name of their company was termed, Acorn. 

Acorn first added a home computer into its arsenal. They worked with BBC for another home computing system for the masses in British land. Initially, the goal was to educate everyone about the use of computers. BBC microcomputers were a huge success for the company in 1982. The system functioned on an 8-bit 6502 processor by Rockwell, the same processor was also working in Apple II. 

Then Acorn realized that the needs of the computing systems were evolving and they needed to evolve with it. Thus, the research and development team at Acorn started something new, a plan for Reduced Instruction Set Computing (RISC).

The Original ARM PC (ARM1)

By 1983, the Acorn company had successfully started working on the first ARM PC. When 1985 rolled around, the first ARM PC was a functional being. They formed something that worked with the standards of 6502 in 32-bit RISC. The chip was encased in a small easy-to-carry device. The small size can be attributed to the hope for cheaper production.

VLSI’s custom design tools helped form the physical chip while the instructions in the ARM PC were written in BASIC. The ARM processor worked from the first time it was sampled, 3µm process was utilized for its making. The ARM1 device went above and beyond the creator’s expectation while it worked on less than 25,000 transistors.

ARM2 Arrives 

The ARM2 processor simply added and then polished the instructions already present in the ARM1 processor. This device was similar in size and still functioned on below 25,000 transistors. The Multiply and Multiply and Accumulate instructions were included in this ARM processor. The result of this instruction addition was the functioning of digital signal processing. 

Digital signal processing was utilized to issue audio and this function held great importance in the educational and home computers. 

ARM Development System had an ARM 2 processor. Acorn’s Archimedes also came with an ARM3 processor in it, it was hailed as a multimedia PC. This ARM PC had ARM2 8 MHz versions with 3 support chips and an input/output controller. However, Archimedes failed to gather as much attention as IBM PC because, at that time, no software could run on ARM. Archimedes was merely a new processor with a new operating system. It was 2 years before software started working on this PC, and from that point onwards, Acorn established itself in the British market as a leader for home and educational PCs. 

ARM3 Joins the Company

Acorn was interested in making ARM the most sought-after processor. The company’s research and development team next made an ARM3 processor that had 4 Kbytes on-chip data. Its clock rate was at 25 MHz, and it had an instruction cache. By the time 1990 rolled around, one could find ARM3 in Acorn’s personal computers. 

ARM2aS

This version of the ARM processor leaned towards lesser consumption of energy. ARM2aS became popular amongst those who wanted to make small mobile devices.

Personal Digital Assistants (PDA)- A Struggle Between Acorn and Apple 

Herman Hauser stepped into the PDA market with a separate company. This company utilized ARM processors for PDAs. It is important to mention that these ARM processors were specifically designed to ensure that the energy loss was controlled. 

Apple entered the PDA market at the same time and their PDA was working on the Hobbit processor from AT&T. Apple wanted to use an ARM processor for its first PDA Newton but was unable to do so because of the strategic position of the company. 

VLSI, Acorn, and Apple later collaborated and at this point, Apple changed the processors in their Newton PDA to ARM processors. 

Advanced RISC Machines Ltd Opens Its Doors

It was at the end of 1990 that ARM Ltd was founded. The function of this company was to create low-powered and high-performance 32-bit RISC processors at lower costs and spread in the arena. 

It was decided by the new CEO that the company would provide ARM processors as a base technology and then ARM processor was licensed as Intellectual Property (IP). 

To this day, ARM Ltd. runs on the very same IP license. This strategic licensing allows the company to work with several partners.

An Overview

The evolution of ARM did not end here. ARM went through many more stages of development from ARM6 Processor to ARMSoC which are extensively covered here.