Re: writing operating systems in ADA

[snidely@nosun.UUCP (David Schneider)]

In article <6991@ingr.com> phil@ingr.UUCP (Phil Johnson) writes:
>Intel attemped to build an Ada-based machine (using Ada to write the operating
>system) but found that it was pretty much a wash. The restricted lexical 
>elements could not support general languages which used characters not allowed
>in Ada (APL comes to mind - ain't no Thumbnail in Ada).
>

I'm sure that most OS writers would be suprised to know that
they had to program in a language which supports "thumbnail"
in *it's* lexical elements for APL to run on that OS.

The 432 died because it was too slow.  The OS was less a factor
than bus problems (but performance improved scalably with additional
processors).

The second generation project also used Ada for the OS,
with a compiler for the 80960 that ran fast and produced good code.
This project, a joint venture with Siemens and yclept "BiiN",
failed for market/project management reasons, not because of
any technical problems with using Ada.

In fact, I would go with Ada as an OS language again.
The important parts are (to the language user) about the
same size as Pascal, and the package concept is useful
to design whether you're doing SASD, JSD, or OOD.
(I will side with Grady Booch and claim that Ada is sufficient
for an object-based design, even if the slim support of
inheritance is a liability).


				Dave Schneider
				late of BiiN