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Date: Wed, 9 Aug 2006 11:35:46 -0700
From: "Rana Dasgupta" <rdasgupt@gmail.com>
To: harmony-dev@incubator.apache.org
Subject: Re: [general] platform support
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Tim,
   Thanks for fixing my quoting. I seem to always mess this up :-)
   Please see below for a couple of points...


On 8/9/06, Tim Ellison <t.p.ellison@gmail.com> wrote:
>
> >But there are degrees to which this is done too right?  Somewhere along
> >the spectrum from a start-up check that chooses between the winxp.dll
> >and win2k.dll, to repeatedly choosing between any number of possible OS
> >function calls.


Yes, my understanding is that though we choose at startup, we will need to
check the flag before many api/functionality invocations.

>Oh, and I'm assuming that we are leaving the jitted code out of this.
> >Of course the jit will know what platform it is targeting and can
> >generate the code appropriately.  So we are discussing the performance
> >
>
>of the interpreter and the compiler itself.


Right Tim and the GC and the thread manager, etc. etc. Jitted code should be
fine.

> The second option is to use a least common denominator approach where
> > we use code/functionality that is only available on the least
> > platform. This is not a good idea for obvious reasons. For example it
> > is not a good idea not to use the excellent vectored exception
> > handling on WinXP and Win2003( which intentionally share the same
> > debug and kernel codebases )If this were not, we would be writing
> > code for DOS only.
>
> >Again, there may be cases where you may well choose the least common
> >denominator solution because it is 'good enough' and the overhead
> >elsewhere (testing etc.) is not worth the gain found here.
>
> >Is vectored exception handling a slam dunk case for making the binary
> >winxp only?  I don't know -- what would happen if we didn't use it?
> >Where is the example in the current code that makes ensuring it runs on
> >W2K unpalatable?


I have tried to answer some of these in a seperate reply as best as I know.

>Agree, so there is a balance to be struck.  But I'm guessing from you
> >descriptions that you favour this approach of multiple distributions for
> >different OS releases.
>
> Yes, I would certainly favor this :-)


Best,
Rana

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