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From Joseph Grace <oc...@serv.net>
Subject Re: FAQ language (was: Unable to run 10.0.2 GA on Mac OS X 10.3.5/VM 1.4.2_05)
Date Sun, 10 Oct 2004 16:25:50 GMT
Wow.  Nice job:  captured the details and neutral.

On Oct 9, 2004, at 11:03 PM, Samuel Andrew McIntyre wrote:
> Workaround:
> For Cloudscape/Derby, the workaround is to set our property 
> derby.storage.fileSyncTransactionLog=true to avoid the code path which 
> uses "rws" mode.

The only bit of information I would add (for Apple's sake) to the 
report is that another workaround exists which is to use "rwd" instead 
of "rws".  That avoids the exception and seems to work as well.

I'm not sure the following belongs in the report, but if a line of 
communication were to open with a helpful member of the Apple JVM team, 
I would also segue to the following questions.  They could shed some 
valuable light on (their JVM, but perhaps also JVM's in general) the 
Derby "rws"/"rwd" issue (as seen on OS X but also a potential gray area 
elsewhere):

1.  Why does "rwd" work where "rws" does not, and what's the difference 
between the two file opening modes?

2.  Is it true that "rwd" safely protects the file contents (including 
any necessary metadata such as new directory inodes) while (safely) 
optimizing out incidental metadata updates (e.g., file-modified times)? 
  If so, is that _the_ (and the only) difference between "rwd" and 
"rws"?

3.  If #2 is affirmative, what metadata updates does "rwd" optimize 
out?  (Hypothetically speaking for now) which (missing) metadata causes 
the "rws" open to fail after an "rw" open on a new file?  [There are 
some other detail questions to insert here if the discussion were to 
get this far, but that's the gist.]

4.  If #2 is affirmative then is it safe to say that Derby (should be 
able to) use "rwd" in general?  And in preference to "rws"?

-=-

Once again, nice report.  Thanks for submitting it (to Apple) and for 
posting it here.  By the way, is there any way to see the report (e.g., 
URL to bugs database) and any followups or status from Apple.  (I 
suspect not but figured it doesn't hurt to ask.)

Cheers,

= Joe =


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