[SAGA-RG] missing(?) method reporting last modification time

[Sylvain Reynaud]

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 <Sylvain.Reynaud at in2p3.fr>
>> To: Thilo Kielmann <kielmann at cs.vu.nl>
>> CC: saga-rg at 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
>>>  
>>>       
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