Happy Birthday VAX 11/780 (influence of)

[arcarlini at iee.org]

Chuck Guzis [cclist at sydex.com] wrote:

> Not to be too much of a wet blanket, but how many of those DEC-unique
> innovations (even if you manage to assert that they originated with
> DEC) persist in today's hardware?  Do modern PCs use memory-mapped
> I/O?  The 68K, but for some Freescale relics, is history.

Given that x86 is king today that means it all goes back to the 4004 :-)

> Major innovations, such as virtual memory and orthogonal instruction
> sets and hardware-implemented stacks preceded the PDP-11.
> 
> Perhaps the major contribution of the PDP-11 and VAX was that they
> were comparatively cheap for the processing power.

Neither VM nor a sensible ISA originated with VAX-11 (or PDP-11) but
these architectures were very popular and exposed many people to these
sorts of features.

Being hugely influential doesn't (necessarily) mean being the first with
anything.

VM, for example, is as old as the hills, I can find references as far
back as Atlas but I'd not be surprised if someone now points out a
known implementation even earlier.

BTW modern PCs are only just beginning to shake off their UARTs: wasn't
that an invention of one G. Bell for the PDP-11? (My "Computer
Engineering"
isn't to hand right now so I may be going out on a limb here ...)

Antonio