Re: Suitability of ada environments for systems development

[Robert Dewar <dewar@gnat.com>]

In article <7lis9r$oil$1@usenet01.srv.cis.pitt.edu>,
  "John Duncan" <jddst19+@pitt.edu> wrote:

> Do vendors provide library implementations of the normally
> OS-dependent features such as tasking and protected objects?
> If so, could vendors please mention how their tools help solve
> these problems? Good responses will facilitate choice of
> platform for a number of users.

That's a bit of an odd note. If you are interested in serious
evaluation of Ada vendors, I suggest getting in touch with the
relevant vendors directly, explaining your needs, and asking
them for details. A very vague request on CLA is unlikely to
draw useful responses.

In the case of Ada Core Technologies, please send a statement
of your requirements to sales@gnat.com. The other vendors have
similar contact points.

The question you ask shows some confusion not at all surprising,
given that indeed in other languages the situation is confusing,
and these are real problems! So now let me make
some completely vendor independent responses that are really
about Ada, and not any particular implementation.

Tasking and protected operations are an integral part of the
Ada language. Consequently *any* Ada compiler MUST provide
completely transparent implementations of all Ada features
including tasking and protected operations. Whether they do
this with library implementations, inline code, direct calls
to the operating system, special hardware operations or
whatever is something that an Ada programmer does not generally
need to be concerned about.

Typically Ada tasks will for example simply map to operating
systems threads.

Basically then tasking and protected operations, while the may
indeed be "problems" in other languages, are not problems in
Ada, they are simply part of the well defined language, and
for details of how these [non-]problems are solved you read
the definition of the language, just as you would to find out
how to add two integers.

Robert Dewar
Ada Core Technologies


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