Re: Robert Dewar's great article about the Strengths of Ada over other langauges in multiprocessing!

["Randy Brukardt" <randy@rrsoftware.com>]

"Maciej Sobczak" <see.my.homepage@gmail.com> wrote in message
news:89af8399-94fb-42b3-909d-edf3c98d32e5@n75g2000hsh.googlegroups.com...
...
> Take for example lock-free algorithms. There is no visible research on
> this related to Ada, unlike Java and C++ (check on
> comp.programming.threads).

Perhaps I'm showing my ignorance, but does there need to be any? Ada
supports lock-free threads quite well using pragma Atomic. I find that the
only locks in my recent programs are (1) those for selecting a new job; (2)
those for protecting the logging resources; and (3) those for protecting
complex data structures (such as pattern sets) that can be updated
asynchronously. The vast majority of the code does not contain any locks.

There's no hope of avoiding the locks that protect shared OS resources -
ultimately devices - you could push them into the OS, but that's about it.
The data structure locks might be avoidable in some cases - but that doesn't
seem language-specific (surely if you can write a lock-free queue algorithm
in C you can write it in Ada - and probably with less games).

If Ada needs anything, it is more emphasis on tasking safety - that is,
detection of unsafe access to shared objects, livelocks, and deadlocks -
that would make it easier to write correct tasking programs. That's clearly
possible in Ada because the threading is an integral part of the semantics
of the language, and it would add value to the existing facilities of the
language.

                                      Randy.