Thilo Kielmann a écrit :
Dear Sylvain,
Dear Thilo,
interesting to hear! (It's a pity that you did not raise this issue before...)
I raised it at OGF23 (see slide 34 of my talk).
I have 2 questions:
1. Where exactly have you added getLastModified? In ns_entry/ns_directory? or in file/directory? Is there a good reason for one or the other place in the hierarchy?
In the ns_entry, because this information is also available with most logical file/directory protocols.
2. Did you add anything else? I mean, did you find any other omissions?
Our deviations from the SAGA specification are listed here http://grid.in2p3.fr/jsaga-dev/SAGA-delta.html But this web page does not distinguish between what we could consider as omissions and personal preferences... Comments are welcome. Best regards, Sylvain
Thilo
On Fri, May 29, 2009 at 03:54:05PM +0200, Sylvain Reynaud wrote:
From: Sylvain Reynaud
To: Thilo Kielmann CC: saga-rg@ogf.org Subject: Re: [SAGA-RG] missing(?) method reporting last modification time A method "getLastModified" has already been added to our implementation (JSAGA) of the SAGA specification in order to fulfil a user request, but using it makes his code dependent on our implementation...
Consequently, I fully support your proposal.
Sylvain Reynaud
Thilo Kielmann a écrit :
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