[TUHS] PDP-11 legacy, C, and modern architectures

Paul Winalski paul.winalski at gmail.com
Fri Jun 29 02:45:39 AEST 2018

On 6/28/18, Theodore Y. Ts'o <tytso at mit.edu> wrote:
> It's the same mistake
> Chisnall made when he assrted the parallel programming a myth that
> humans writing parallel programs was "hard", and "all you needed" was
> the right language.

I''ve heard the "all you need is the right language" solution to the
parallel processing development problem since I joined DEC in 1980.
Here we are in 2018 and nobody's found that "right language" yet.

Parallel programming *is* hard for humans.  Very few people can cope
with it, or with the nasty bugs that crop up when you get it wrong.

> The problem is that not all people are interested in solving problems
> which are amenable to embarassingly parallel algorithms.

Most interesting problems in fact are not embarrassingly parallel.
They tend to have data interdependencies.

There have been some advancements in software development tools to
make parallel programming easier.  Modern compilers are getting pretty
good at loop analysis to discover opportunities for parallel execution
and vectorization in sequentially-written code.

-Paul W.

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