On Fri, 31 May 2024, Linus Torvalds wrote:
> The fact is, the original alpha is the worst architecture ever made.
> The lack of byte instructions and the absolutely horrendous memory
> ordering are fatal flaws. And while the memory ordering arguably had
> excuses for it ("they didn't know better"), the lack of byte ops was
> wilful misdesign that the designers were proud of, and made a central
> tenet of their mess.
>
> And I say that as somebody who *loved* it originally. Yes, the lack of
> byte operations always was a pain, because it really caused the IO
> subsystem to be a nightmare, but I was young, I was stupid, it was
> interesting, and I had bought into the kool aid.
Looking from today's perspective it was clearly a bad choice. However it
was 30+ years ago, it wasn't so certain as it is now that x86 was there to
stay -- indeed as I recall it DEC had the ambition to phase x86 out with
their Alpha (whether they approached it the right way business-wise is
another matter) -- so the notion of having a fully byte-addressed machine
perhaps wasn't yet so obvious to DEC engineers as it is now, when most if
not all the current CPU architectures have these fundamentals the same.
As I say it may have been the final attempt to do something differently
before x86 domination forced everyone to be at least remotely compatible.
And there used to be weirder architectures before people moved away from
them and settled on the current paradigm, just as nobody wants to build a
general-purpose atmospheric railway anymore and yet a while ago not only
it didn't appear ridiculous, but such stuff was actually built and run,
such as the South Devon Railway.
And then it wasn't the only failed attempt: remember the i860 or the
iAPX432? At least the Alphas weren't a total disaster, they made their
impact, the worst mistakes have been fixed as the architecture evolved,
and the engineering legacy remains, often in unexpected places.
Maciej
