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From "Geir Magnusson Jr." <ge...@apache.org>
Subject Re: [arch] VM Candidate : JikesRVM http://jikesrvm.sourceforge.net/
Date Sat, 21 May 2005 19:15:34 GMT

On May 21, 2005, at 12:08 AM, Steve Blackburn wrote:

> Mark Brooks wrote:
>> Investigation is fine enough, but let's face facts.  This is a  
>> HUGE project.
>> We do NOT have the time or manpower to write two VMs as part of a  
>> project where we need a working J2SE 5 implementation, from  
>> basement to TV aerial so to speak, and we need it in time to be  
>> relevant.  Even with donated code, it won't work to do VMs in  
>> parallel.
> I think it would be insane to develop multiple VMs in parallel.
> Fortunately, I don't think anyone is proposing that.

I hope not.

I'd really like to see

0) Lets remember the timescale here - this is going to be years,  

1) A little more discussion around the parts that go into a VM, no  
matter what language we're working in.

2) People playing with the existing VMs we're talking about using.   
These right now are all open-source VMs - you can get them now and  
play with them.  We call can.  We don't need to move them here.  We  
might choose to do it later, or we might choose to start over if our  
analysis of what came before leads us to that conclusion.

> The seeding model I have pushed would only have multiple VMs on the  
> table during the seeding process.  That is something I envisage  
> would take three to nine months.  During that time the community  
> will have the opportunity to engage with the projects and gain much  
> needed experience and insight into how a real VM is built.   
> Concurrently new cores would be architected and built. The VM cores  
> are small but they are the centerpiece and getting them right is  
> critical.  Therefore, as far as the cores go, I am much less  
> concerned about person power than I am about informed design  
> decisions.  The bulk of the work is going to be in achieving  
> completeness, improving packaging, fixing known shortcomings,  
> smoothing corners etc etc.

Yes - and we can start *right now* without having them here.

> With a strong component based model, different configurations could  
> be built for different purposes.  This is not a radical idea nor is  
> it rocket science---we already do it in Jikes RVM (you choose your  
> compiler and your GC ahead of time and tailor the VM accordingly).   
> I am sure other VMs do this as well.  If we're going to try to  
> cover the desktop, servers and embedded devices, then reuse is  
> going to be key.

Yes, and this is one of the original premises of the project.  It  
would be nice to start that component model discussion :)


> --Steve

Geir Magnusson Jr                                  +1-203-665-6437

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