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<div style='border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm'>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>In the last few months,
we've been experimenting, more and more seriously with a technology being
developed by the San Diego Supercomputer Centre known as SRB (Storage Resource
Broker). See</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> <a
href="http://www.npaci.edu/DICE/SRB">http://www.npaci.edu/DICE/SRB</a></span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>It is a technology also
being very well supported by the UK's e-Science initiative in conjunction
with SDSC.</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='text-indent:36.0pt;border:none;padding:0cm'><font
size=2 face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial'><a
href="http://www.e-science.clrc.ac.uk/web/projects/storage_resource_broker">http://www.e-science.clrc.ac.uk/web/projects/storage_resource_broker</a></span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>At ISIS, we have decided
to use the technology as the means for us to access our data archive on the
Atlas peta-byte data store (where we currently store our archived data but in a
different format). This however is an almost trivial use of the system, by
it's very nature it encompasses the concept of a global file system set
up between co-operating establishments and accessible from anywhere with a
variety of interfaces (web, PC client, Java, command line on anything).</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>We are currently running
a test system before we go live with real data later in the autumn; it is
however a bit sterile because although it does all we need, we are only working
within the local site. To really see the potential of the system it would be
nice to get a handful of people to join servers to the network (in test data
mode only!) and see how the exchange of experimental (and other) data can
really work between establishments. To get a feel for SRB and how it works, I
would entreat you to try _<i><span style='font-style:italic'>both</span></i>_
the windows client (INQ) in demo mode and the MySRB web client demonstrators
(both available on the SDSC site). For more serious use a command line or
language APIs are also available.</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>If you are in the
(relatively small) group of systems administrators who have the job of
archiving and making users data available to them, and after having a play with
the demos are interested in joining up a test server (it is necessary to be
familiar with a Linux style manual build and install - or Windows if it's
just a basic server) and have the ability to open some specific firewall ports
to the world, it is however, probably only a ½ hour job to get a basic server
running. Please e-mail me for more info; we would simply need to add the
address of your server into our network to make it a member and then create a
user or two for you to try things out.</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>Best regards,</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>Chris Moreton-Smith</span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>The Proposal</span></font></p>
</div>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The motivation for NeXus is to allow the exchange of
data between programs, instruments, establishments and branches of science
where the neutron, muon and X-ray technologies are the common theme. Recently
the NeXus community has been greatly (and crucially) occupied with choosing
what data to store in a file and how it should be described in a common
fashion.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>This proposal tackles a complementary facet of the
broader problem; namely the exchange of the data files themselves between the
programs, operating systems, instruments and establishments.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>Most scientists doing experiments on instruments at
different establishments will have experienced the joy of trying to copy data
off a variety of different computer systems, often being forced to network a
laptop machine at the last minute, write a CD or floppy disk before racing to
catch a flight, manually select and copy files one at a time via ftp and/or
negotiate a firewall to get at their data. If very lucky, maybe they have been
able to download data from a conveniently set up web site, where remembering
the password has been the only problem.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>If this state of affairs wasn't bad enough,
there are things that are even harder to do than read your data. For example,
you might want to send a few calibration files and sample setup notes to a
remote site ready for an experiment. This would normally be seen as folly
unless you have a trusted colleague already on site to help you receive and
look after the files. And what if you've forgotten a file you needed on
arrival? Wouldn't it be nice if you could do a bit of data reduction on
site and then continue at home, all the time saving the reduced files in the
same directory as the raw data (and with no need to copy the data locally).
And then permit a colleague to access a few of the files from their own laptop
whilst at home (by setting permissions like you do on a local Unix NFS file
system or Windows share)?</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>There is really very little reason why we should
accept such a desperate state of affairs. With the help of the UK's e-Science centre we have been experimenting with the San Diego Supercomputing
Centre's SRB (Storage Resource Broker) for several months now. This
provides at a minimum a very credible and functional globally distributable
file system.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'>The proposal is in three parts.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal style='margin-left:54.0pt;text-indent:-18.0pt'><font size=2
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial'>1)<font
size=1 face="Times New Roman"><span style='font:7.0pt "Times New Roman"'>
</span></font></span></font><font size=2 face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial'>We adopt SRB as a working system on
which to experiment with building a global integrated network for sharing
Neutron, Muon and X-Ray data between our establishments and our users. We do
this pragmatically (like we have done with HDF) because it currently seems to
do the job and support is what standards like this need to develop.</span></font></p>
<p class=MsoNormal style='margin-left:54.0pt;text-indent:-18.0pt'><font size=2
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial'>2)<font
size=1 face="Times New Roman"><span style='font:7.0pt "Times New Roman"'>
</span></font></span></font><font size=2 face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial'>More fundamentally, we extend our
remit of defining and organizing data types within the NeXus file to also
giving some sort of standardisation to the organisation and location of data
within a global file system. Quite simply, this just avoids things being lost
by everyone storing things under different names and in different places (for
example, a naming convention for raw files).</span></font></p>
<p class=MsoNormal style='margin-left:54.0pt;text-indent:-18.0pt'><font size=2
face=Arial><span lang=EN-GB style='font-size:10.0pt;font-family:Arial'>3)<font
size=1 face="Times New Roman"><span style='font:7.0pt "Times New Roman"'>
</span></font></span></font><font size=2 face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial'>Even more fundamentally, we spend
some effort defining the sort of meta-data which we might associate with each
file (possibly not contained in the NeXus file itself). This meta-data would
enable a data portal style search engine, just like a super data-Google quickly
to find relevant data by searching throughout this global file system. Some of
this sort of work is already underway but some sort of standardization of the
type and contents of this metadata is very close to the sort of standardization
we are aiming at with the NeXus file contents and would greatly ease the
ability to search and find relevant information.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<div style='border:none;border-bottom:solid windowtext 1.0pt;padding:0cm 0cm 1.0pt 0cm'>
<p class=MsoNormal style='border:none;padding:0cm'><font size=2 face=Arial><span
lang=EN-GB style='font-size:10.0pt;font-family:Arial'>The sheer use-ability of
this particular system, especially for quite a young technology is staggering.
This is not something to be planning for next year or the year after,
it's something to be using now - and then planning how to build a
data storage and access strategy around it. NeXus has taken a long time to
grow to the point where we are able to agree on the most difficult issue of
what is common within our data files, this is because it's a <i><span
style='font-style:italic'>really</span></i> difficult job. Taking some
responsibility for (2) and (3) in particular is a lot less work but is
something best tackled early.</span></font></p>
</div>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=EN-GB style='font-size:
10.0pt;font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=1 color=navy face=Arial><span lang=EN-GB
style='font-size:7.5pt;font-family:Arial;color:navy'>--<br>
Chris Moreton-Smith, Software Development Manager<br>
ISIS Science Instrumentation, CCLRC, Chilton, Didcot, OXON OX11 0QX<br>
Telephone: +44 (0) 1235 446544, Fax: +44 (0) 1235 445720<br>
Email: </span></font><span lang=EN-GB><a href="mailto:C.Moreton-Smith@rl.ac.uk"><font
size=1 face=Arial><span style='font-size:7.5pt;font-family:Arial'>C.Moreton-Smith@rl.ac.uk</span></font></a></span></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-GB
style='font-size:12.0pt'> </span></font></p>
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