[Samba] SOLVED was Re: Any ESRI users? Upgrade 3.0.14 to 3.0.21a broke Arcmap layer loading?

Jeremy Allison jra at samba.org
Wed Feb 1 02:17:21 GMT 2006


On Tue, Jan 31, 2006 at 08:54:43PM -0500, Elizabeth Schwartz wrote:
> 
> Thanks for the headsup! I've been reading about oplocks (including the
> HOWTO) and it sounds like we don't need 'em. If I understand the HOWTO
> correctly, they don't sound like the world's greatest idea. Our network is
> reasonably fast and our user applications aren't moving tons of data back
> and forth. It's still puzzling me why oplocks are even *in* this picture
> since the ESRI applications should be opening files read-only, but maybe
> they aren't.
> 
> I *am* wondering why the default setting for oplocks is on, when they sound
> somewhat risky. Do some Microsoft applications take it ill if they aren't
> available?

No, but some Microsoft applications have *very* poor performance
if they're not there. They aggregate system calls for bad programmers.
Want to read a file a block at a time, then re-open it and read the next
data block then close and do it again ? Some Microsoft apps (old versions
of Office) do this.....

UNIX programmers learn early on to use aggregate functions to avoid
system calls, as the cost of too many of them becomes apparent. oplocks
hide that inside a clever redirector so Windows programmers never have
to learn this lesson unless they want to.

Jeremy.


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