New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...
New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...
New Statistical Algorithms for the Analysis of Mass - FU Berlin, FB MI ...
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5.5. QAD GRID PLATFORM SERVICES 139<br />
identification string will be used later to match this service with workers<br />
and tasks. Fur<strong>the</strong>r, description and specification <strong>of</strong> <strong>the</strong> input parameters<br />
used and <strong>the</strong> output <strong>for</strong>mat have to be specified.<br />
2. The service request is reviewed by a QAD Grid administrator and ei<strong>the</strong>r<br />
accepted or denied.<br />
3. In case <strong>of</strong> a positive decision that new service is automatically inserted<br />
into <strong>the</strong> QAD Grid database.<br />
5.5.2 Service Integration<br />
The QAD Grid system allows so-called worker injections (see section 5.3.3).<br />
This means, if triggered by some event (e.g. new tasks <strong>of</strong> a particular kind are<br />
available), <strong>the</strong> QAD Grid server can log into some client machine and start a<br />
worker on that machine able to handle this task.<br />
To enable this feature a service needs to be integrated into <strong>the</strong> QAD Grid<br />
system. Integration <strong>of</strong> a service requires <strong>the</strong> following steps:<br />
� The service must be successfully registered (see above) at <strong>the</strong> system.<br />
� Each worker implementation needs to be registered at <strong>the</strong> QAD server -<br />
again, through a web-<strong>for</strong>m. This includes<br />
– description,<br />
– version number,<br />
– operating system(s) this worker runs on (e.g. Linux or Windows),<br />
– hardware plat<strong>for</strong>m(s) this worker runs on (e.g. Intel or Cell/BE),<br />
– 3rd party library dependencies,<br />
– class path,<br />
– command-line to start this worker.<br />
Each 3rd party library used by this worker must be available at <strong>the</strong><br />
QAD Grid server. This is to avoid redundant storage <strong>of</strong> libraries within<br />
<strong>the</strong> Grid and <strong>the</strong>re<strong>for</strong>e multiple transfer <strong>of</strong> files to a client. Fur<strong>the</strong>r, by<br />
providing verified libraries through <strong>the</strong> QAD Grid server no misuse can<br />
happen. Missing libraries need to be requested and will be integrated<br />
into <strong>the</strong> system by an QAD Grid administrator.<br />
� The actual implementation <strong>of</strong> this worker needs to be available at <strong>the</strong><br />
QAD Grid server zipped into one archive. This zip archive is also transmitted<br />
through <strong>the</strong> web-<strong>for</strong>m (see above). When a worker is injected<br />
into a client this zip archive is transferred and unzipped at <strong>the</strong> target<br />
directory (see section 5.3.3).<br />
5.5.3 Task Submission<br />
Submission <strong>of</strong> tasks to <strong>the</strong> QAD Grid is done by calling a stored procedure<br />
at <strong>the</strong> database. This call needs to include <strong>the</strong> task id string and <strong>the</strong> task’s<br />
parameters. The stored procedure <strong>the</strong>n checks<br />
� whe<strong>the</strong>r <strong>the</strong> task’s id string is valid<br />
� whe<strong>the</strong>r <strong>the</strong> sender is allowed to submit new tasks<br />
If <strong>the</strong> checks are positive <strong>the</strong> task is inserted into <strong>the</strong> system’s task queue.