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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Newsgroups: comp.lang.ada
Subject: Re: Ada platforms and pricing, was: Re: a new language, designed
 for safety !
Date: Wed, 25 Jun 2014 20:24:20 +0300
Organization: Tidorum Ltd
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Xref: news.eternal-september.org comp.lang.ada:20594
Date: 2014-06-25T20:24:20+03:00
List-Id: <comp.lang.ada>

On 14-06-23 10:42 , Dmitry A. Kazakov wrote:
> On Mon, 23 Jun 2014 09:18:11 +0300, Niklas Holsti wrote:
> 
>> I am currently working on an Ada project with a null run-time and a
>> proprietary small multi-threading kernel.
> 
> Wouldn't it be helpful to have user-defined tasking for such cases?

I haven't felt a need for that.

> Because there is another important case for this - co-routines.

I don'like them, at least not as substitutes for tasking. They can be a
way to interface and interleave two or more sequential algorithms in one
task, in a controlled way.

> When implementing
> stuff like network communication (e.g. HTTP servers) and parallel
> processing we frequently have a set of state machines (one per connection)
> too expensive to handle from OS tasks. Programming a state machine is
> turning all design upside down. If there were user-defined task support one
> could program this as if it were in proper tasks.

The proposals for "lightweight" tasks that I have seen have more
constraints and ugly limitations than I would like. Even Ravenscar
constraints are often annoying. Better OS support for Ada tasking would
be preferable. I'm not convinced that the best and fastest designs for
Ada tasking systems have been discovered yet.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
      .      @       .