[TynesideLUG] Fwd: Your Computer is not a Fast PDP-11

[Jeff Joshua Rollin]

Oops, I meant to send the last message to the LUG.


Anyway, speak of the Devil and he will establish a Foundation:

https://www.phoronix.com/scan.php?page=news_item&px=Rust-Foundation



-------- Forwarded Message --------
Subject: 	Re: [TynesideLUG] Your Computer is not a Fast PDP-11
Date: 	Mon, 8 Feb 2021 14:46:43 +0000
From: 	Jeff Joshua Rollin <jeff at jeffjoshua.club>
To: 	Alex Kavanagh <alex at ajkavanagh.co.uk>




On 08/02/2021 10:01, Alex Kavanagh wrote:
>
>
> On Sat, 6 Feb 2021 at 20:01, Jeff Joshua Rollin <jeff at jeffjoshua.club> 
> wrote:
>
>     Hi,
>
>     I mentioned during today's LUG having read a paper a few years ago
>     which
>     complained that modern C is still coded (and indeed the language was
>     designed) to expose a virtual PDP-11 to the programmer. I didn't
>     think I
>     would find it again but, having Googled, I think I have. (If it's not
>     the same one, it basically touches on the same points.)
>
>
> I don't think it is as clear cut as to say "modern C is still coded 
> ... to expose a virtual PDP-11".  It /was/ coded that way and inertia 
> tends to maintain the design pattern because, simultaneously, during 
> the last 40-odd years, processors have also been coded to a particular 
> execution model to get the best performance out of the dominant 
> systems language: C.  So they effectively seem to have locked each 
> other into a vicious cycle of maintaining the status quo.
>
> It would have been interesting if the Transputer 
> <https://en.wikipedia.org/wiki/Transputer> had made more of an impact, 
> as it begat the concurrent programming languages occam (and occam 2).  
> But the ideas did end up in AMD/Intel in how to interlink CPUs and 
> other chips together.


Yes, it's slightly more complicated than that. Admittedly some of that 
article went a little bit over my head, but I'm learning.

It will be interesting to see what happens with any of the current crop 
of operating systems being coded in Rust; I'm sure you're aware of at 
least some of them - and of course there's software other than OSes 
being coded in Rust too. IIUI correctly, the RISC-V ISA doesn't try to 
help programmers doing concurrency in any way, although to date I think 
their focus has mostly been in embedded systems where perhaps it's not 
as important as trying to keep multicore desktops and servers occupied 
as much as possible. It does allow for extensions, however, so perhaps 
in future they will end up having to add them. The fate of all 
(successful) ISAs seems to be to grow larger and larger...

Had to look up the Transputer again. For some reason I thought it was 
based on multiple MC68K's; perhaps I'm thinking of something else, or 
perhaps it was because Atari tried their hand at one (the Atari ST and 
successors used MC68Ks, like pre-PowerPC Macs, Commodore Amigas, and 
early Suns). Yet another example of innovative technology being squashed 
by the market and economies of scale, I guess.

>
>
>     It's available online at
>     https://queue.acm.org/detail.cfm?id=3212479
>     <https://queue.acm.org/detail.cfm?id=3212479> (no
>     charge), and there is also a link to a PDF of the article on the
>     same page.
>
>     Hope this is of interest to someone,
>
>     Jeff.
>
>
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>
>
>
> -- 
> Alex Kavanagh
> Home: http://alex.kavanagh.name <http://alex.kavanagh.name>
> @ajkavanagh