Re: Ada compiler for Windows NT

[vnet.IBM.COM@uunet.uu.net (Charles Reichley)]

In <24amci$3pv@schonberg.cs.nyu.edu> dewar@cs.nyu.edu (Robert Dewar) writes:
>
> Alsys has certainly announced its intentions in this area (I hope I am not
> giving away company secrets by saying that the intentions are backed up by
> some very nice technical work, but I don't know the release status, contact
> Alsys directly). Meridian was demonstrating an NT compiler at the last
> Tri-Ada a year ago.
>
> One thing to understand here is that there are many ways of writing a piece
> of software that is nominally NT, ranging all the way from a thin warming
> over of a Windows app to a full reimplemtation that takes advantage of NT.
> The other thing to realize is that NT is realy a collection of operating
> subsystems with a common Kernel. Usually people are talking about Win32 whn
> they ask this kind of question, but you need to be sure the guy who is
> answering your question is on the same wavelength.

It seems to me that when discussing Ada and operating systems, what we
would be looking for is how well the Ada compiler uses the underlying
operating system functions to provide the Ada features, such as
multi-tasking.  A DOS ada compiler would have to provide its own
run-time in order to provide for a tasking model.  With an OS such as NT
or OS/2, the operating system has a multi-tasking model, so the Ada
compiler could (in OS/2 for example) use 'threads' to implement tasks.

Providing interfaces to various OS GUI APIs would also be useful, but
secondary.

Of course, just having a tasking model in the underlying OS doesn't mean
that the Ada compiler is going to use it, for example the SunADA
compiler for Sun OS 4.1.x doesn't use processes for tasks (an
unfortunate situation, since for what we are working on now we are
writing multiple ada programs and using pipes and shared memory for
communication since we need our tasks to be separate processes -- coming
off a program that made extensive (and I think proper) use of Ada
tasking (which I feel, having worked on several multi-tasking programs
now, is one of Ada's best features), it really is hard to abandon the
tasking model.
>
> Finally, people have asked, and will no doubt ask more energetically now,
> whether there is an NT version of GNAT. The answer is that we have waited
> till NT is available to even think about this, but now that I can get NT
> in my local Software Etc (a bunch of $295 boxes were up on the wall), I
> guess that time has come! In fact we definitely expect an NT port of GNAT,
> since NT is perfectly capable of supporting GNAT. We will still concentrate
> on the OS/2 version for now, since our main priority is on impleementing
> additional functionality on our current ports (OS/2 and Sparc) rather than
> doing new ports of what we have. Eventually of course we expect to have
> lots of ports (our experience so far is that in fact it has been easy to
> port what we have if you know enough about GCC to do cross-compilations,
> we have in house ports to Alpha, RS-6000, HP, MIPS etc).
>
> By the way, one of the reasons that we think the OS/2 version more significan
t
> is that, especially with glue factory disasters, we think it likely that ther
e
> will be more PC's around with th 6 megs (8 megs really) that OS/2 requires
> rather than the 16 megs (20 megs really) that NT requires!
>


Charles W. Reichley,   IBM FSC, Manassas, Va.
Reminder : This post has nothing to do with IBM or its subsidiaries