Croquet VM issues

Andreas Raab andreas.raab at gmx.de
Fri Mar 17 01:59:51 UTC 2006


Hi Tim -

>> 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.
> 
> Those changes were incorporated LAST APRIL. If you had bothered to 
> actually build a VM with any vmmaker since then you'd have found them in 
> as agreed. The latest vmmaker can be found on SM, along with several 
> earlier versions.

No reason to get upset. I was just asking for a status update. I checked 
with 3.8b4 as reference version since all the others have big fat 
disclaimers on them about "use at your own peril etc." and 3.8b4 (btw, 
SqueakMap says it's from september '05) does not contain these changes. 
They first show up in 3.8b5-64 (from december '05). And talking about 
versions what *is* the latest stable version? SqueakMap lists 3.8b5-64B 
as the latest; is there any version that is either newer or considered 
"non-beta" or both?

>> * @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.
> No, there is no vmmaker repository.

Okay, can we agree on one? Say, source.squeakfoundation.org?

>> 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) 
>>
> Yes, and .... what? I have no record of anything going beyond a vague 
> suggestion. How would this have anything to affect vmmaker? You want to 
> use it, you change your makefile settings.

I didn't say it would affect VMMaker. I am trying to find out whether it 
is possible on various platforms to checksum the VM since we have very 
specific requirements (like float behavior) for Croquet. Also, in the 
post back then I was asking the question about what people would think 
about building entire VMs using fdlibm. That's still on the table (but 
the lack of comments back then makes me think that I'll probably opt for 
a MathPlugin instead of fixing the VMs internally).

>> Questions:
>> * On Mac and Unix, do we implement getSystemAttribute: -1 to return 
>> the full path to the executable?
> See http://minnow.cc.gatech.edu/squeak/314 This is a spec that was 
> agreed to about 8 years ago. If any platform is non-compliant it should 
> be brought into compliance asap.

It's actually not clear to me what is "compliant" in this case. For one 
thing, is reporting the name of a shell script that starts Squeak 
compliant for system attribute 0? (I would think so) For another, is the 
name of the VM part of the "negative set" of attributes (yes for Windows 
but mostly for historical reasons since system attribute 0 used to be 
reported in 8.3 naming style)?

>> 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.
> Submit them in the usual manner and I'll look at them sometime.

Will do, thanks.

> As far as I'm concerned the 64 bit stuff is pathetically sulking in a 
> corner due to almost nobody having paid it any attention.  I have done 
> everything reasoanble for vmmaker but there are a largish number of 
> places where there are 'flag: #dan' type comments and there are places 
> where there are comments about some change needing work someday. The 
> only VMs I know of that have been built and released with the 64bit 
> changes incorporated have been on RISC OS and OSX so to the best of my 
> knowledge there is no information on whether they are any use on windoze 
> or *nix. I was considering backing out all the changes since it seems 
> that nobody cares even fractionally enough to finish what they started.

Well, as always, I guess the lack of an actual user base is problematic 
here. And my main problem is that I don't know much about the actual 
changes that happened (I know them on the large scale, yes, but not in 
detail) and since these things went back and forth I am just not certain 
what the current status of them is.

On the other hand, if John has been using those changes for OSX VMs and 
not gotten a whole lot of horrible complaints I think I'm willing to 
take that risk.

Cheers,
   - Andreas



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