[TUHS] A New History of Modern Computing - my thoughts

Bakul Shah bakul at iitbombay.org
Mon Nov 29 11:47:21 AEST 2021

Was B, or rather BCPL, influenced by Algol68? It too had
	<var> <op>:= <value>
as a shorthand for
	<var> := <var> op <value>
Its declaration
	<type> <name>
is the same as in C. Though in A68 this was a shorthand for
	ref <type> <name> = loc <type>

> On Nov 28, 2021, at 1:31 PM, Ken Thompson <kenbob at gmail.com> wrote:
> The PDP-11 had very little the syntax of B expressions.
> All of that was in place in B long before the PDP-11.
> To be honest, the byte addressing of the 11 was a
> significant hindrance. It was the genius of Dennis
> that was able to conquer the 11 as he installed types
> into the language.
> So, my opinion, the PDP-11 had no design on the
> type system of C and moreover it was not even helpful.
> On Sun, Nov 28, 2021 at 1:17 PM Jon Steinhart <jon at fourwinds.com> wrote:
> Rob Pike writes:
> > Is there a symbiosis between C and the PDP-11 instruction set? The
> > machine was vital to C and Unix's success, but primarily due to the
> > availability of a department-sized machine. Was the instruction set a
> > significant component? Most Unix programmers wrote little to no
> > assembly, although perhaps more read what came out of the compiler.
> > But did it matter? Auto-increment and -decrement are often cited in
> > this story, but they are not that important, really, and were around
> > well before the PDP-11 made its appearance.
> >
> > I'm curious to hear arguments on either side.
> >
> > -rob
> Well, might just be my personal experience, but most of the machines
> that I had used before the 11 were classic accumulator architectures.
> I feel that the 11's pointer architecture combined with autoincrement
> and autodecrement was an amazing fit for C.  If I remember correctly,
> it was very cool to have *p++ = *q++ be a single instruction.
> BTW, one thing that I forgot in my earlier post is that I think that
> the book also omitted any mention of Creative Commons.  The book did
> talk about the business of the web and such, and it's my opinion that
> CC was an an essential third prong.  The machines were one, the software
> was another, the third was content and CC was a big enabler.
> Jon

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