Re: Porting ADA source

["Robert I. Eachus" <rieachus@comcast.net>]

Randy Brukardt wrote:

> Case in point: when we ported Janus/Ada to the U2200 computers, we had to
> change a lot of assumptions about the sizes of things. (We had of course
> assumed character = byte = 8 bits, and of the U2200 was a 36-bit word
> machine.) Rather than simply coding a different set of assumptions, we
> decided to restructure everything so that the compiler depended on a small
> set of packages that encoded host and target information. That eliminated
> future redos for similar issues. I'm sure the customer would have been
> happier in the short run if we hadn't restructured everything, but it meant
> that virtually all bug fixes only needed to be made once -- a huge time
> savings in the long run.

I'll second Randy on this first.  Quick and dirty gets to "sort of 
working" faster, but doing it right seems to get to working faster, and 
definitely gets to no bugs much faster.

However, there is an issue here that may require living with two 
versions for a long-time: the need to compile using the DEC Ada compiler 
which AFAIK is Ada 83 only.  I believe that GNAT is available for some 
Alpha OSes.  (I don't know which Unix variant this is.)

I think that the right path forward would be to migrate the code to 
GNAT, then use the GNAT version on the Alpha system.  It may be a lot 
simpler than any other approach, and it certainly should reduce the 
support costs going forward.

-- 

                                           Robert I. Eachus

"The flames kindled on the Fourth of July, 1776, have spread over too 
much of the globe to be extinguished by the feeble engines of despotism; 
on the contrary, they will consume these engines and all who work them." 
-- Thomas Jefferson, 1821