Alan Ralph

Wearer Of Many Hats


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How an obscure British PC maker invented ARM and changed the world

Jason Torchinsky, Ars Technica:

If you were writing reality as a screenplay, and, for some baffling reason, you had to specify what the most common central processing unit used in most phones, game consoles, ATMs, and other innumerable devices was, you’d likely pick one from one of the major manufacturers, like Intel. That state of affairs would make sense and fit in with the world as people understand it; the market dominance of some industry stalwart would raise no eyebrows or any other bits of hair on anyone.

But what if, instead, you decided to make those CPUs all hail from a barely-known company from a country usually not the first to come to mind as a global leader in high-tech innovations (well, not since, say, the 1800s)? And what if that CPU owed its existence, at least indirectly, to an educational TV show? Chances are the producers would tell you to dial this script back a bit; come on, take this seriously, already.

And yet, somehow, that’s how reality actually is.

This is a potted history of how Acorn Computers came to develop the first ARM chip design back in the late 1980s, thanks in part to the BBC, plus a lot of engineering talent.

One part that I’d not been aware of previously was that things could have turned out very differently:

As everyone with any urge to read this far likely knows, the 1980s were a very important time in the history of computing. IBM’s PC was released in 1981, setting the standard for personal computing for decades to come. The Apple Lisa in 1983 presaged the Mac and the whole revolution of the windows-icons-mouse graphical user interface that would dominate computing to come.

Acorn saw these developments happening and realized they would need something more powerful than the aging but reliable 6502 to power their future machines if they wanted to compete. Acorn had been experimenting with a lot of 16-bit CPUs: the 65816, the 16-bit variant of the 6502, the Motorola 68000 that powered the Apple Macintosh, and the comparatively rare National Semiconductor 32016.

None of these were really doing the job, though, and Acorn reached out to Intel to see about implementing the Intel 80286 CPUs into their new architecture.

Intel ignored them completely.


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