Re: Real time Java? Huh?

["Charles R. Lyttle" <lyttlec@flash.net>]

oopster@my-dejanews.com wrote:
> 
> In article <3642a327.38883600@news.nmia.com>,
>   joconnor@roadrunner.com wrote:
> > On Thu, 05 Nov 1998 21:36:10 -0800, Joseph <**********@*******.**>
> > wrote:
> >
> > >I missed way too much of this thread.   Java as a real time language?
> > >Tell me that this is a hoax, please.
> >
> > That gist of it is that some companies are breaking with Sun and
> > trying to establish a standard for Java in real time systems.
> 
> More accurately, the gist is that Sun has a proposed standard for real-time
> Java, and a group of other companies has also formed a consortium to promote
> a somewhat different realtime Java standard.  The main issue seems to be the
> licensing terms for Sun Embedded Java.
> 
> HP has already produced a competing embedded Java VM, which they are also
> licensing to other companies.
> 
> > I remember being at a Alsys demonstration once where one of the Ada
> > compiler writers warned against using exception handling in hard real
> > time systems because you couldn't guarantee how long it would take to
> > unwind to find the handler for the raised exception.  I wonder if such
> > conditions esist for exception handling in Java?  (Or dynamic
> > dispatch, for that matter)
> 
> Is it still the case that Ada exceptions are to be avoided for real-time?
> Not a good thing if true...
> 
> It seems clear that deterministic exception handling will be critical to
> real-time Java efforts.  I'm sure you can find out more about this at the
> various real-time Java websites if you're interested.
> 
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Exceptions are never to be used in Ada ( or Java) for any reason other
than to catch totaly unpredictable disasters. Java IOStreams will have
to be completely re-written if Java is to be used in hard real-time
systems. Until then don't use ^D or ^Z to  end an input stream.

-- 
Russ Lyttle, PE
<http://www.flash.net/~lyttlec>