Croquet VM issues

[Andreas Raab]

Hi Folks -

Since we're nearing release status I was going over the VM requirements 
for Croquet to see if we could just go with a bunch of standard VMs or 
whether we'd need some customized ones. Looking over some recent VMMaker 
versions, it turns out that there are actually a few important bits and 
pieces missing from the current VMMaker release which we will want to 
use in Croquet.

Most importantly, we need the following issues resolved:

1) GC improvements: As discussed in April last year
(see 
http://discuss.squeakfoundation.org/cgi-bin/ezmlm-browse?list=vm-dev&cmd=showmsg&msgnum=184)
we need the weak array fixes and the GC measurements/tweaks that John 
did. Those actually turn out to be important for us, if only for 
analysis of current behavior.

Questions:
* What's the general status of those changes? The way I understand the 
discussion we had back in april, is that John did the adjustments to 
64bit and then ... what?
* @Tim: Does a VMMaker repository exist by now? Like I was saying back 
then, I am not alltogether happy with the current situation of new 
releases just popping up on SqueakMap and with no way of seeing what's 
in there and how things have developed.

2) Floating point accuracy: As discussed in november last year
(see 
http://discuss.squeakfoundation.org/cgi-bin/ezmlm-browse?list=vm-dev&cmd=showmsg&msgnum=365)
we need consistent floating point behavior across platforms. I'm 
actually in the process or rolling out a bunch of tests for it which 
will be based on fdlibm as described in the above message. One issue 
that is critical here is that I am planning to checksum (SHA1) the VMs 
while we are running Croquet to see if the VM is "compliant" (if not 
we'd run a whole suite of tests to verify the behavior).

Questions:
* On Mac and Unix, do we implement getSystemAttribute: -1 to return the 
full path to the executable?
* On Mac and Unix, can one read the executable while running Squeak? I 
need this to checksum the VM proper.

3) Some Socket fixes: David Reed made some changes for Sockets which 
turn out to be critical in particular on Macs and Unix systems. I'm 
still in the process of bundling up these changes but they are fairly 
straightforward so I don't see many issues with them.

Besides the above three, I have one additional question: What is the 
general status of the 64bit work right now? Do we consider this complete 
or work in progress or experimental? Can we rule out any ill effects for 
the 32bit VMs?

Thanks and Cheers,
   - Andreas