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From Geir Magnusson Jr <g...@pobox.com>
Subject Re: [general] platform support
Date Sat, 12 Aug 2006 13:21:50 GMT


Elford, Chris L wrote:
> Any _primary_ platform that will be supported by Harmony will probably
> need to be put thru a pretty full test protocol on that platform
> independent of whether it uses the same binary or a different binary. 

Yes - the testing for a given platform is independent of the platform.

> I
> doubt that the Harmony community will want to target all possible OS
> combinations initially.  I think that we should have a serious
> discussion on this list about the OS combinations for which we have
> "volunteers on board" for "Harmony 1.0".

We are having one.

> 
> I don't believe that Harmony should achieve ubiquity by using least
> common denominator interfaces.  For x86 32bit-mode systems, I do think
> we'll probably need to limit ourselves to one or two binaries.

Hang on - do you think anyone is advocating ubiquity via LCD interfaces?
 What we needed was a focused discussion on the technological
trade-offs,  and I think we're having one.  I also think that calling
them "LCD" is somewhat of a charged phrase, as it pre-judges the
usefulness or appropriateness.  For example, using something specific to
XP might not be any better but be just some kind of lock-in feature...

> 
> See http://java.sun.com/j2se/1.5.0/system-configurations.html and
> http://edocs.bea.com/jrockit/jrdocs/suppPlat/supp_50.html a list of what
> combinations Sun and BEA support today with their Java5 solutions.
> 
> I am unconvinced that a combined binary will make testing any easier.  

I know it was mentioned, but I don't think anyone is seriously
suggesting it as a major motivation because we have to test on any
platform we claim to support.  The combined binary will make life easier
for users and distributors.

This started as a debate over whether or not we will even support win2k,
 because people were trying to use harmony on it.

>I
> believe that the makefile (oops, I mean ant) structure will be easier
> with a combined binary but the startup code and some platform specific
> optimization code will be more complex as it will need a pretty
> sophisticated platform determination and a somewhat manual library
> loading process.  At the same time, I believe a combined binary that
> includes multipath checks will simplify distribution.  I also believe
> that something similar will be necessary for Linuxes though perhaps not
> as sophisticated.

Right.  Exactly.

> 
> Lets say that we decide to go for "complete", "optimal", windows
> support.  We would have special case code that chooses appropriate
> library interfaces at startup for somewhere between 7 and 18 different
> versions of x86 windows, not accounting for service packs:
> * x86 Vista home, pro, tablet
> * x86 Vista/Longhorn server, webserver
> * x86 Vista/longhorn enterprise

Do you think this software will ever be released? :)  It would be
interesting to see if what we have runs on Vista now.  Anyone have a
copy running?

> * x86 XP home, pro, tablet, media
> * x86 XP/2003 server, webserver, Enterprise, Datacenter
> * x86 W2K 
> * x86 W2K Server, W2K Advanced Server, Datacenter
> 
> This of course doesn't account for the either EM64T or Itanium family
> processor based systems.  Maybe someone needs to take each OS platform
> and list what special interfaces are useful for each one.  I'm
> particularly partial to some of the interfaces available only on the
> server versions such as the large page APIs:
> http://windowssdk.msdn.microsoft.com/en-us/library/ms694004.aspx.
> 
> http://windowssdk.msdn.microsoft.com/en-us/library/ms724833.aspx talks
> about how to distinguish the different versions and service packs from
> each other.  This is probably pretty useful information to report back
> to JIRA in the case of a VM crash if we have a single binary release
> model.  Of course if one wants to be able to run on windowsMe or
> Windows98, one can't rely on these interfaces...  But then since these
> aren't actively supported by Microsoft anymore, its unclear how relevant
> those platforms are.  

I think fairly irrelevant, but if someone did step up and wanted to do
the work, I wouldn't stand in their way :)

geir


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