Re: Ada in Embedded Systems Programming.

[jmills@ccrf-news.gatech.edu (John M. Mills)]

In article <1994Oct27.080032.1@corning.com>,
whiting_ms@corning.com (Matt Whiting) <whiting_ms@corning.com> wrote:
>
>Has anyone other than me read the most recent edition of "Embedded Systems
>Programming" magazine (Vol. 7, Number 11, Nov. 94)?  It contains two
>interesting articles: one about Ada directly, and one that uses Ada as the
>vehicle to illustrate another point.  I found both very good reading.

Yes, I enjoyed reading these articles.  Each was useful, but the article
on system engineering an automobile cruise control was particularly
gratifying in that it addressed realities of what I consider "software
engineering" as contrasted to "computer science."  On the other hand,
the satellite-borne controller described in the cover article (by Richard
Riehle) describe a system actually realized in Ada, whereas the cruise
control would presumably be recoded for smaller targets than supported
by most Ada compilers:  "I wrote the Ada design with an assembly language
solution in mind." -[author]  He also specifically refers to Ada typing
models which will enhance the protability and/or focus attention on
implementation requirements for the eventual targets [i.e., multi-precision
fixed-point arithmetic].  I find this a quite useful insight.

I believe the "all or nothing" approach to Ada's design has shut it out of
a lot of this class of applications, quite aside from Ada's other qualities
as a development language: by that, I mean that I am unaware of
a compiler which would target (say) an 8051, following code development and
analysis on a larger platform.  I'm afraid I consider the common "Show me a
design that couldn't be done in Ada" response to be foolish and immaterial if
the application environment can't accept the targets which Ada compilers can
support.  The Riehle article mentions some [Ada legal] suppressions which
enable them to target a 64Kw memory space.  In retrospect, more elaborate
switches to turn Ada language features on and off might have been a good
design approach.

(Nomex gloves and safety glasses are now in place!)

Regards --jmm--

-- 
John M. Mills, SRE -- john.m.mills@gtri.gatech.edu -- (404)528-3258 (voice)
   Georgia Tech/ GTRI/ SDL, 7220 Richardson Rd., Smyrna, GA 30080
     Inez Has Tiny Fuzzy Poodles - II'67