Re: Ada and Automotive Industry

[Richard Riehle <rriehle@nunic.nu.edu>]

On 27 Nov 1996, Robert Dewar wrote:

> Well of course it is impossible to optimize output from C to match assembly
> performance,

  [ snip, snip ]

  Agree, Robert. And in many situations, it would be unnecessary to
  be concerned with this issue. It happens that for the processor
  in question, it is of concern.

> But in practice an awful lot of assembly language is NOT written that
> competently, and in particular I have often seen perfectly awful
> algorithms coded in a furiously optimized manner.

  Agree again. I recall a programmer who took an assembler program that
  required 15K of memory on a 16K machine, optimized it to 12K for the
  same machine, leaving 4K unused.  Completely silly exercise because
  the program was subsequently unreadable.

> You have to remember
> that the above argument has been used over time to try to object to the
> use of C or other high level languages on any machine, but as time goes
> on, people understand that sometimes high reliability is more important
> than saving a few bytes. 

  My antiquity is such that I do indeed recall such arguments. My comments
  on this thread are restricted to the discussion of a particular 
  microcontroller, the 8051, not to the entire microprocessor industry.

> Sure I understand a car company is happy to save $1/car for millions of
> cars, but that is still not a good deal if the consequence is an
> increased risk of catastrophic failure resulting in expensive lawsuits.

  Although this thread originated with opinions about the automotive
  industry, it turned toward the 8051 in particular.  The fact is that
  the 8051 is used for more projects outside the automotive industry
  than within it.  I know of projects on the 8051 that  would surprise
  you.  
 
  Now, for the Ada plug. I know of at least one software developer that
  is re-engineering their 8051-based product to a different processor,
  one that supports Ada, with plans to use Ada as its development
  language on that new processor -- for safety reasons.  And this is
  a commercial developer with no, underscore NO, connection to the
  Department of Defense.

> Of course a GNAT port to the 8051 (or any other machine), would not be
> usable for all applications, but probably it would be usable for some
> fraction of them. 

  Agree that GNAT or some some other Ada compiler might be well-suited
  to a fully configured 8051, i.e. one with a full complement of
  external data space and external code space.  Many 8051's are more
  modestly configured.

> However, I still don't think there is a market.
> Counting the number of projects is not the point, you have to count the
> number that might reasonably be persuaded to use Ada. I think that number
> is very small. 

  Agree on this too. The number, though higher than one might imagine,
  is not as important as the percentage of that number who could be
  persuaded to use Ada.  And that number is likely to be very small.

  Richard Riehle