Questions and more questions. 
Author Message
 Questions and more questions.

A few years ago, our CS school had a guest lecturer who
spoke about real time garbage collection in Smalltalk.

He described a method to collect garbage and yet provide
the responsivness necessary for real time.  The solution
seemed simple enough.

Now, I am not addressing the Mandate.  It is just that
I find both Ada and Smalltalk interesting.  

Smalltalk seems well designed, consistent and robust.  Why
not Smalltalk in real time apps.?

Further, I have little experience with Ada.  Is there a
development environment for Ada that is similar to, say,
ParcPlace Smalltalk?
--

Jodrey School of Computer Science   |  smail : PO Box 1406
Acadia University                   |          Wolfville NS B0P 1X0



Thu, 06 Feb 1997 08:36:55 GMT  
 Questions and more questions.

Quote:

>Further, I have little experience with Ada.  Is there a
>development environment for Ada that is similar to, say,
>ParcPlace Smalltalk?

As my late father would say, "From your mouth to God's ear..." :-)

Seriously - one of the really strong points about Smalltalk is that
it was developed, right from the start, as an integrated interactive
environment. As you know, the Smalltalk project at Xerox PARC was
also the origin of a lot of GUI ideas that found their way over
to the Apple LISA and then the Mac (actually, they didn't just "find"
their way - Apple hired several key Xeroids).

It would be very nice if Ada were as well integrated with IDE's as
Smalltalk, but that was not Ada's origin or its main purpose.
Indeed, bitmapped displays did not really become popular till after
the Ada standard was pretty well fixed. (No Mac till 1984; the LRM
was adopted as a standard in 83.)

Interestingly enough, there were two starts on integrated environments
for Ada, involving interpretive execution of procedures, Ada procedure
calls as command lines, etc. One was done at UCI, in the Arcturus project,
and another by (I think) Unisys as part of the ARPA STARS project.

I have never gotten what I'd call a satisfactory explanation of why both
these projects were halted _just_ as they were about to really bear fruit.

The STARS one, which was called ACE (Ada Compilation Environment) is
available in the PAL and on the CD. It is written in Ada and some
curious mind might get interested in playing with it. There is a
vt100-ish UI and (if memory serves) also an X one. IMHO, it's darn shame
that for reasons never made publicly clear, the thing got stopped
just before the point of real viability (this was around '91).

I don;t know at all why the UCI project was never finished; maybe the
sponsors (ARPA again) got different ideas. Anyone out there who was
around UCI at the time care to comment? How 'bout the STARS project?

There certainly are X-based Ada-tailored GUI's out there - for sure
Rational Apex and Alsys' product (I forget ther name) are in this
category. I don;t think they are as well integrated as Smalltalk,
but this is not surprising because Smalltalk and its GUI grew _together_.

Mike Feldman



Fri, 07 Feb 1997 10:43:58 GMT  
 Questions and more questions.
Another question comes to mind concerning Ada and objects. (btw,
thanks foe the replies).

A recent publication from Bell-Northern Research concerning OO
software development, said that they are making a major effort
to catalog the various objects that are created in the course
of their work.

The article went on to say that (or imply) that one can have
too much of a good thing, that is, too many objects duplicating
work already created.

So, I would suggest that as we grow into 9X, that an important
area of research will be the cataloging of objects and an
expert system to help the programmer find what is needed in less
time than it would take to create it from scratch.

I realize that this is called software re-use, and I have read
Ada Letters and the relevant CACM articles.  It seems to me,
however, that a tri-Ada research program in this direction
will pay immeasurable dividends.

I will see if I can't find that article again. I really must
get a filing cabinet...

--

Jodrey School of Computer Science   |  smail : PO Box 1406
Acadia University                   |          Wolfville NS B0P 1X0



Sun, 09 Feb 1997 19:50:54 GMT  
 
 [ 3 post ] 

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