July 2009 - saga-rg - lists.ogf.org

missing(?) method reporting last modification time
by Thilo Kielmann 29 Sep '09

29 Sep '09

Folks, within our group we are currently delving into issues with accessing remote file systems. What strikes us is that such access is SLOW. As such, it would be very beneficial if one could find out when (and thus whether) a remote file or directory has been modified. While returning this piece of information sounds to be "trivial", it strikes us that the SAGA spec has no such call in the name space package (where files reside). In POSIX terms, this is the info returned by the stat system call (see: man 2 stat), with the st_mtime parameter. In Java, files have a method lastmodified(). Both POSIX and Java report the time in milliseconds since 01/01/1970 (epoch). Of course, it looks like nobody has ever been thinking about such a use case, but here we are! Our feeling is that the last modification time is very essential meta data about files, so such a call should certainly be there. With our current problem certainly not being the only use case for finding out how old/new a given file or directory is... Our favourite proposal is to add a method that returns the last modification time to both ns_entry and ns_directory as this makes sense with physical as well as with logical (replicated) files. Any reactions/objections ??? Thilo Kielmann -- Thilo Kielmann http://www.cs.vu.nl/~kielmann/

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revised sd spec (gfd.144)
by Steve Fisher 17 Aug '09

17 Aug '09

Hi, As nobody objected I have made the changes to the SD spec. I attach the .pdf file. There is a changelog as required by the new procedure. Also see the comments in the errata file (also attached) For details of the changes see CVS and compare HEAD with the tag v-1 Steve

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adapter should mkdir working_directory?
by Yutaka Kawai 17 Jul '09

17 Jul '09

Hello, I'm Yutaka Kawai @KEK, woriking for SAGA adapter implementation for NAREGI and PBS. I have a question about adapter behavior for working_directory. If a user specify a working_directory in the job description but the directory does not exist, what is the suitable adapter's behavior? Should the adapter throw "DoesNotExist"? or mkdir the directory for the job? In the case of the current NAREGI, it mkdir the working directory in constructing its WFML. On the other hand, PBS does not. I want to decide whether adapters absorb the difference or not. Could you tell me the case of LFC also? Regards, Yutaka -- Yutaka Kawai 河井裕 High Energy Accelerator Research Organization (KEK) Computing Research Center Tel: +81-(0)29-864-5200 (Ext: 4503) Fax: +81-(0)29-864-4402 E-Mail : yutaka.kawai(a)kek.jp

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SD Spec Proposed Errata
by Steve Fisher 09 Jul '09

09 Jul '09

We propose to make the following changes to the SD spec - attribute names to start with a capital letter This has already been discussed and agreed - add attribute "InformationServiceUrl" containing a ref to the source of the information We want this so that it is possible to determine where the information has come from. It will not be possible to use this attribute for selection - use the URL in the discoverer constructor instead. Note that it is "InformationServiceUrl" rather than "InformationServiceURL" - add attribute "ImplementationVersion" - taken from the corresponding GLUE field - add attribute "InterfaceVersion" - taken from the corresponding GLUE field - add multi-valued attribute "Capability" to match the GLUE-2 capability which in turn uses the OGSA defined set of values This was discussed within a small group at LSU F2F This will be more useful than the current "Type" as service types tend to be peculiar to one grid. The description of type will simply say: "type of service. This API does not restrict values of the service type - it might be a DNS name, a URN or any other string." and table 1 will be deleted. Comments please

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