Re: Ada tasking

[ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)]

In article <1921@cod.NOSC.MIL>, sampson@cod.NOSC.MIL (Charles H. Sampson) writes:
: In article <20075@grebyn.com> ted@grebyn.com (Ted Holden) writes:
: >Tasking is naturally an operating system feature; ...
: An interesting, unequivocal, statement.  No "IMHO ...", no "Many people
: think ..."

Given that Ted Holden cited Hoare, I don't think it irrelevant to remind
people who invented the CSP notation (which underlies occam, for example).
That's right.  Hoare.

The last time I heard an argument like that, it was the Algol 60
committee saying that input/output was naturally an operating system feature.
Algol 68 not only specified I/O, Algol 68 had a tasking model!

It doesn't matter whether tasking is done with special syntax or by
calling built-in procedures.  If I can use it in a portable program,
the effect of the tasking operations has to be defined _somewhere_.
The fact that fork() and signal() and semop() and the rest are library
functions in UNIX/C just means that (a) when I write a C program that
needs IPC I have to look in a language manual _and_ a library manual
and (b) my programs aren't portable.  This is a help?

The advantage of a separate tasking library is that several languages can
use the same library.  There's a lot to be said for that.  But the point
of Ada was to _reduce_ the need for using several languages.
-- 
"A 7th class of programs, correct in every way, is believed to exist by a
few computer scientists.  However, no example could be found to include here."