Dynamic Loading of Code

Dynamic Loading of Code

[Kenneth Anderson]

Is there a way to dynamically load ada code into a running Unix process?
For instance, lets say that a program has been set up to call a procedure
to implement some sort of behavior and that during run-time you would like
to load new code into the process (which replaces the current procedure)
so that you can dynamically change the behavior of the system.  Never mind
why I would want to do this, currently, I'm just interested if its possible
to do this.

Thanks in advance,

Ken Anderson

P.S. Thanks for all of the responses that I received about my
     What's the Difference and ANSI vs ISO posts.  I really enjoyed
     the response that the former received!

Re: Dynamic Loading of Code

[Steven V Case-1]

In article <9302151904.aa29489@Paris.ics.uci.edu> kanderso@mabillon.ICS.UCI.EDU
 (Kenneth Anderson) writes:
>Is there a way to dynamically load ada code into a running Unix process?
>For instance, lets say that a program has been set up to call a procedure
>to implement some sort of behavior and that during run-time you would like
>to load new code into the process (which replaces the current procedure)
>so that you can dynamically change the behavior of the system.  Never mind
>why I would want to do this, currently, I'm just interested if its possible
>to do this.

I do not have my copy in front of me at the moment, so I cannot look up the
exact reference.  Anyway, I remember a paper that was presented at Tri-Ada
'91 which was related to this matter.  If you can locate a copy of the
Tri-Ada '91 Proceedings you might find the paper of interest.  I wish I 
could remember the title of the paper.  I'll try to look it up tomorrow
and send you an e-mail with the exact reference.

I seem to remember the paper presenting an approach to dynamically 
replace "modules" for software systems that must have very high availability,
such as banking systems.  The general approach was to use a very disciplined
communication protocol between these modules.  The protocol supported
the "transfer", if you will, of messages from an old copy of the module
to a new copy of the module.  In effect, you had a very controlled manner
of loading updated software without shutting the system down.

Regards,
Steve Case