In a message on 09-05-94, Craig Swanson said to Louis Rizzuto:

CS> OS/2 gives fairly low interrupt latency times and ...
  :
Is this from personal experience?  Can you please provide any kind of
hard results you may have accumulated?  I would find this to be of
tremendous help in deciding how to go ahead with my long-term plan to
port my applications from DOS to OS/2.  

("The Design of OS/2", at least, states that the maximum interrupt
disable time is 400 microseconds!  *I* don't call that "low", do you?)


[The rest is editorial comment...you may speed read through it :-)]

CS>Another consideration is the consequences of a delayed event
CS>response. Now if you are writing a data acquisition system, perhaps
CS>it means you loose a small amount of data.  But if a data update is
CS>going to be sent at regular intervals often enough to meet your needs
CS>even if you miss every other sample, maybe that doesn't matter.  
  :
Just as an aside to anyone reading this, what Craig describes is a
perfect example of something that falls into the class of systems that I
call "soft" real-time.  Basically, you would really like real-time
response but if you don't get it from time to time, nobody dies and
nothing blows up.  (This is probably the majority of real-time
applications for which OS/2 is suited.  I'd love to hear hard evidence
to the contrary.)


CS>possible to write a fast program in C++ -- you can use inline
CS>functions and other features that ANSI C does not have to help you in
CS>this effort.
  :
Good point.  Though many programmers use macros for similar things in C,
many don't and inline functions in C++ are at least one way where a
program could be *sped up* by using C++ instead of C.


CS>There are plenty of arguments for C++ along the lines of code reuse
CS>and more rapid program development once the programmers get up to
CS>speed on C++ and use its features fully.
  :
Hear, hear!


Peter Hansen  ***  Engenuity Corporation  ***  Guelph, Ontario, Canada
Internet: peter.hansen{at}canrem.com    RelayNet:->CRS    FIDO:(1:229/15)
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