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Date: 12 Aug 93 14:44:10 GMT
From: mdisea!mothost!schbbs!news@uunet.uu.net  (David Tannen)
Subject: Re: Language runtime requirements (was Re: DoD
Message-ID: <1993Aug12.144410.7915@schbbs.mot.com>
List-Id: <comp.lang.ada>

[stuff deleted]

>Ada has a problem with running well on UNIX systems, partially because
>its tasking model doesn't match that of UNIX.  

Not always so.  I am currently working w/ a Verdix compiler and I believe
that all the Ada tasks (200 in the system I am working on) are "mapped"
to Unix processes.  The compiler takes care of all the implementation 
details - I just write Ada code.

I also worked w/ a DDCI compiler for a bare-bones 80286 system that took
advantage of the environment to make task switching very fast.  Sort of
"mapped" Ada tasks to x286 virtual machines (I may be wrong about my
explaination on this one - its been a while.  But task switching was
very fast.)

>The IEEE POSIX standards
>efforts have tried to resolve that somewhat.  It would not surprise me
>if some aspects of Ada cannot run WELL on Windows NT, for similar
>reasons.  Any language that assumes its runtime has control of the
>environment will have problems.

The Alsys compilers I have worked w/ seem to make the assumption that
their runtime is in charge no matter what the OS is.  There are advantages
and disadvantages to this.  I would think that one advantage is that
if the application is ported to another HW/OS environment you would get 
task processing would be "similiar" between the two environments.  Of 
course it doesn't take advantage of whatever "tasking" support may come
w/ the environment.

>Since Ada makes so many such
>assumptions (tasking, exception control, file control, etc.) it must
>have problems.  This makes Ada more than a programming language.  It is
>also an operating system requirements specification.

>So the question really isn't if you can write a program in Ada that
>will execute in a Windows NT environment.  You can pretty much write
>ANY program in ANY language that will run in ANY environment, with
>enough effort.  The real question is whether you you can build a system
>in Ada that effectively runs in a Windows NT environment without using
>a much effort tailoring it to that environment.  

Actually I think the real ? will be if any vendors "map" Ada tasks to
NT's thread mechanism.  If they do this could be a great advantage for
programming NT applications in Ada.  Of course someone needs to provide
GUI interface tools, and a library of components like Borlands OWL or
Microsofts library support.

Any vendors out in net land want to comment?  Any of you folks going to
compete head-to-head w/ Microsoft/Borland for the NT market?  Or have
you all already given up on that market too?  (I already got burned 
waiting for Alsys to deliver a promised compiler for MS-Windows 3.1.
And I won't ever use a Meridian compiler again - if I can help it.)

(IMHO [honest, haven't been humble for a long time])


---
David Tannen
tannend@source.asset.com
tannen@tigger.geg.mot.com
----------------------------------------------------------------------
-- "Dependance on wizardry to mitigate the fundamental limitations
--  of software is called 'hacking'."  Grady Booch.
--
-- Developing MS-Windows applications often requires 'wizardry'.
----------------------------------------------------------------------