Re: Ada tasking

[sampson@cod.NOSC.MIL (Charles H. Sampson)]

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 ..."  A good illustration of the depth of the author's understanding
of the issues.

IMHO, many people think that the purpose of a programming language is to
express programs.  If a program is implemented using tasking, it seems
ideal to be able to express the tasking part of the program in the same
language that expresses its loops and procedure calls.  Those who de-
veloped the Ada requirements (Ironman, Steelman) had the radical idea
that it should be possible to understand a program by reading its source
code, rather than getting out the operating system services manual.

>                                                ...  Probably what you
>want to do is to define a standard set of features to be provided by
>operating systems/real-time kernals for uses which involve tasking, a
>standard set of function calls, and have libraries to provide these
>functions to applications which need them.

Maybe I missed something here, but this sounds like an argument in favor
of putting tasking into the language.  The only quibble seems to be the
syntax to be used (and presumably the semantics).  Should it be done
with constructs that look like declarations and statements, or should
it be done with "a standard set of function calls?"

None of this is intended to cover up the fact that there are problems
in this area.  I can't believe that there is anyone who believes that
Ada's tasking is just wonderful and should not be touched.  My guess is
that if anything is certain to be modified in 9X, it's tasking.  Of
course, that version 1 of Ada is imperfect is considered proof of its
worthlessness by Mr. Holden.  Does anyone remember what version 1 of
C looked like?

Charlie Sampson, CSC