Re: Ada 95 tasking problems with Ada 83 code

[Bill Dale <william.dale.jr@lmco.com>]

Wayne Lydecker wrote:
> 
> I am porting a huge program from Ada 83 on HP-UX to GNAT Ada 95 on a PC
> running Linux.  

I would recommend a two step process.  First get the code running with 
Gnat Ada95 on the HP-UX system.  This eliminates any Ada95 or Gnat
issues.  
Then port to the PC using Gnat Ada 95.   

Creating the executable was not a big problem, but I
> can't get it to run very far.  It appears that when a procedure rendezvous'
> with a task, the task won't run.  The task has a simple accept statement,
> and it appears to accept the rendezvous because the calling routine
> continues to process.  Text_IO calls before and after the accept statement
> in the task fail to appear on the screen though.  If I put a "do ... end"
> on the accept statement then the caller no longer continues (i.e.
> suspended).
> 

If you are running on Windows any real-time performance is not
predictable.  Windows is not a real-time OS or even close.   

The comments about Rate Monotonic Analysis of your tasking design are
very valid.  
I recommend "Concurrency with Ada" by Weller as a good reference on Ada
95 tasking issues.


> Is this a known problem?  Is there a solution other then removing all
> tasks in our program (over 100).
> 
> Thanks,
> 
> Wayne Lydecker
> wayne@visicom.com


William L. Dale
"If we spend all of our time in ADM's talking about TLA's we'll be SOL!"
Speaking for myself 
Lockheed Martin, Space Systems Company,
Missiles & Space -Sunnyvale Operations
mailto:william.dale.jr@lmco.com