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From Greg Trasuk <tras...@stratuscom.com>
Subject Re: Retrotranslator - Small Devices?
Date Fri, 27 Mar 2009 15:23:20 GMT

I say, forget small devices.  Jini is network infrastructure for service
oriented architectures.  The mention of small devices is the root of
Jini's adoption problems in the first place ("Jini? that has something
to do with discovering printers, right?"). Let's not make that mistake
again!


Cheers,

Greg.

On Fri, 2009-03-27 at 09:58, Peter Firmstone wrote:
> I agree with Jonathan, Dennis and Jim, however I think Patrick has 
> raised a good point.
> 
> Retrotranslator allows you to use new Java l.5 language features which 
> require compiling on jdk 1.5 or later, the class files compiled by Jdk 
> 1.5 or later once Retrotranslator has altered them, will run on jre 1.4 
> or even jre 1.3 since Retrotranslator packages additional compatibility 
> classes into the jar file, but only those required.    The question is 
> then; what are the memory limitations of JavaME 1.4.2 CDC Devices?
> 
> It would be no longer possible to compile with jdk 1.4 however still 
> possible to run on jre 1.4.    It also means that once we drop support 
> for jre 1.4 we have all the performance benefits of the new concurrency 
> libraries with the latest JRE.
> 
> We might also (at some later date, I think it's ambitious) be able to 
> use the Retrotranslator JIT class compiler to translate classes from 
> code repositories on the fly for earlier jre's participating with later 
> versions in a heterogeneous environment, while allowing the later jre's 
> to make use of newer library performance advantages without sacrificing 
> compatibility.
> 
> I had a look at Java PhoneME Advanced J2ME CDC 1.4.2:
>     
> http://wiki.java.net/bin/view/Mobileandembedded/PhoneMEAdvancedGSGWinMobile
> 
>     There's an optional setting there to set the Device Emulator RAM 
> size to 256MB
> 
> Then on http://www.8mobile.org/blog/?cat=2 :
> 
> An Early Access release of the new Java Platform Micro Edition Software 
> Development Kit 3.0 is available for download. This SDK supports CLDC, 
> CDC, and Blu-ray Disc Java (BDJ) development. Emulation is a major 
> focus: on-device deployment, on-device debugging, integration with 
> devices running Windows Mobile and integration with third-party 
> emulators are just a few of the new features in this preview
> 
>     Windows Mobile 6.0 platform installed on a target device with 
> network connectivity, 32-bit RISC based microprocessor, and minimum 64 
> MB RAM.
> 
> Ricoh Photocopiers also have J2ME CDC, they actually may be able to 
> perform some very useful functions with River?
> 
> Anyone on the list have more experience with Small Devices?  Do we need 
> to decide what the minimum J2ME CDC device requirements are?  Do we pick 
> a Sun J2ME CDC emulator and test on that?
> 
> Perhaps there is a Subset of Java 1.5 features we can use?  If we can 
> determine a compact subset, agree upon it and post it on the Rivers 
> Developers page, we might be able to have the best of both worlds?
> 
> Cheers,
> 
> Peter.
> 
> 
> 
> Jonathan Costers wrote:
> > I agree with Dennis and Jim. We should be looking foward, not backwards.
> >
> > To add to Jim's point, I believe there are probably more urgent things to do
> > than upgrade the complete River distribution to be using post-1.4 features.
> > Then again, when introducing new things, we should not limit ourselves to
> > 1.4.
> >
> > Best
> > Jonathan
> >
> > 2009/3/27 Jim Waldo <Jim.Waldo@sun.com>
> >
> >   
> >> I have to agree with Dennis. Most of us are now using 1.6; 1.7 is underway.
> >> I don't think the small device space should be much of an issue; most of
> >> those devices won't support a full Jini function anyway, since they lack
> >> class loading (that's why we did the surrogate architecture).
> >>
> >> Going back and upgrading to post-1.4 features throughout can probably wait.
> >> But that is no reason not to use them when they make sense in new code.
> >>
> >> Jim Waldo
> >>
> >>
> >> On Mar 27, 2009, at 7:45 AM, Dennis Reedy wrote:
> >>
> >>
> >>     
> >>> On Mar 27, 2009, at 720AM, Patrick Wright wrote:
> >>>
> >>>  Just because the current River codebase is limited to 1.4 doesnt mean new
> >>>       
> >>>>> work should be constrained to that right?
> >>>>>
> >>>>>           
> >>>> I think one has to be careful with compatibility across small-device
> >>>> VMs, which, AFAIK, in some cases are 1.4 compatible (cf. JavaME).
> >>>>
> >>>>         
> >>> Well, and IMHO, keeping the core of River based on a technology that is
in
> >>> it's EOL transition period (http://java.sun.com/j2se/1.4.2/) for the sake
> >>> of *possible* use for small device deployments may not be ideal.
> >>>
> >>> Dennis
> >>>
> >>>       
> >>     
> >
> >   
-- 
Greg Trasuk, President
StratusCom Manufacturing Systems Inc. - We use information technology to
solve business problems on your plant floor.
http://stratuscom.com


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