[Wylug-announce] Next Meeting - Monday 11th December 2000 (fwd)

[Jim Jackson]

Greetings all,

Gnome night was good - with a real live gnome app developed as a demo - hello
"hello world" !! Thanks to Ben and Nigel for the Gnomery.

I have some talks planned for the new year - see the web site - but would ask
for more volunteers for presentations. Anyone feel like doing a short talk on
their favorite app. etc? Email me with ideas and suggestions of talks you'd
like to hear.

Can I encourage people to join us for the meal on Monday night - just email
Rob Speed <RobS@viclabs.co.uk> to make sure he knows numbers.

Apologies for the late arrival of this notice - wrong sort of leaves on the
keyboard or something. The speaker on Monday is Matthew Wilcox who will be
giving our first real Linux Kernel development talk. It might sound a bit on
the heavy side, but without the likes of Matthew we wouldn't be here. Come
along and see what's involved in kernel development.

The meeting will probably finish round about 8:30pm to enable people to get 
to the eatery.

Matthew writes

"The software featured is under the GPL and has just been integrated into
the Linux kernel (version 2.4.0-test9).

Abstract:

This paper describes how the Linux kernel was extended to supply Leases &
Directory notifications to applications.  Leases allow an application
to be notified when a file is modified, allowing that application the
opportunity to cache changes until such time as they must become visible
to others.  Directory notification allows an application to be notified
when the contents of a directory change.

Both of these features were added to enhance the performance and
correctness of the Samba SMB file server, but have applications
beyond this.  In the specific case of Samba, leases allow clients the
optimisation of lazily committing data to the server which is a major
performance gain in most cases.  Directory notification allows Samba to
support correctly the SMB operation of the same name instead of faking
it by polling the directory every 30 seconds.

Other applications for these enhancements can be envisaged.  One obvious
application is a file manager which uses directory notification to ensure
that its display is constantly up to date.  Unfortunately, Nautilus has
opted to use imon/fam and this paper discusses why this is a bad model.
A make `daemon' could also be developed which watches for changes to
directories (eg new versions of files being written) and automatically
rebuilds the project.

A further enhancement which was made to the kernel was the addition of
DOS/Windows `Share Modes'.  These permit one application to deny any
further applications the right to open a file.  As part of these changes,
the current POSIX file locking code was improved.  Finally, the holy grail
of multi-protocol file serving was realised --- NFS locks and SMB locks
were made to interact correctly.
"

All the best
Jim

==========================================================================


                West Yorkshire Linux Users Group  (WYLUG)

             Meetings are free and open to anyone to attend.
                          ----             ------

                     7 pm  Monday 11th December 2000
                        (6:30pm for coffee/tea)

        Presentations:         

                     Leases & Directory Notification
                            Matthew Wilcox

     Abstract: This talk describes how the Linux kernel was extended
       to supply Leases & Directory notifications to applications. 
        These features were added to enhance the performance and 
              correctness of the Samba SMB file server, 
                 but have applications beyond this.




        WYLUG Venue:  Active Learning Lab.,  (Level 7, near staircase 2)
                      E.C. Stoner Building   (aka Physics/Admin)
                      University of Leeds
                      Woodhouse Lane
                      Leeds UK

             for location of Leeds University & Campus Map see
                http://www.leeds.ac.uk/campus/location-maps.html
                http://www.leeds.ac.uk/campus/physa-1.html 
                http://www.leeds.ac.uk/campus/campusmap.html

        General Discussion:

                LINUX  -  News, Views, Question and, hopefully, Answers

                WYLUG  -  what, who, when (and why :-)
                 Especially what happens at future meetings!


-------------------------------------------------------------------------
WYLUG - West Yorkshire Linux User Group     Secretary: jj@comp.leeds.ac.uk
http://www.wylug.org.uk         email lists: http://list.wylug.lug.org.uk






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