[hdf-forum] provenance

[Mark V]

On Wed, Mar 25, 2009 at 9:23 AM, Quincey Koziol <koziol at hdfgroup.org> wrote:
> Hi Dimitris,
>
> On Mar 24, 2009, at 5:14 PM, Dimitris Servis wrote:
>
>> Hi Quincey
>>
>> sorry it was not clear. I meant the UUID. If I copy the HDF5 "internal"
>> UUID from one file to another along with the accessible contents, I do not
>> need to manipulate the time stamp of the target file to be the same with
>> that of the source file, so that applications that depend on the stamp will
>> not tell the difference. I ask all applications to check the UUID.
>
>        Hmm, I don't think copying the UUID to the new file is a good idea -
> the UUID for each file created by the HDF5 library should be unique.  The
> new file should get its own UUID...
>

This seems to come down to the question:
Does the UUID refer to:
 a)  the file at a point in time, irrespective of contents.
 b)  the file contents at a point in time.
 c)  the file contents irrespective of time.
 d)  whatever the user wants it to refer to as 'unique'.

I may misunderstand the intended usage. However it would be useful to
document which is the intended use case.

I'd be interested in (d) since it opens the scope for domain specific
use cases.  I think the first 3 can be accommodated in some way by OS
level data?

Mark

>                Quincey
>
>> thanks!
>>
>> -- dimitris
>>
>> 2009/3/24 Quincey Koziol <koziol at hdfgroup.org>
>> Hi Dimitris,
>>
>>
>> On Mar 24, 2009, at 3:41 PM, Dimitris Servis wrote:
>>
>> Hi Quincey
>>
>> if it would be possible to copy it, I would also be interested. My use
>> case is this: when deleting large objects from the file, I copy all objects
>> to a new file and delete the old one. But some applications may depend on
>> the time stamp of the file and therefore I would have to modify the time
>> stamp of the new file using OS functions. Any unique ID would solve this.
>>
>>       Are you wanting to copy objects' access/modification/etc times, or
>> the UUID for the file?
>>
>>               Quincey
>>
>>
>> thanks!
>>
>> -- dimitros
>>
>> 2009/3/24 Quincey Koziol <koziol at hdfgroup.org>
>> Hi Matthew,
>>
>> On Mar 24, 2009, at 1:32 PM, Matthew Dougherty wrote:
>>
>> Is there a unique identifier internally within an HDF file when it is
>> created?
>>
>> Something that would distinguish it from another HDF file created two
>> seconds later, and cannot be disabled or modified.
>> Do not want to use the operating system/file system creation date or
>> parameters in fstat, prefer a HDF api.
>>
>>      That's a good idea...  Would a UUID fit what you are thinking?
>>  (http://en.wikipedia.org/wiki/Uuid)
>>
>>              Quincey
>>
>> On Mar 24, 2009, at 5:11 AM, Quincey Koziol wrote:
>>
>>      BTW, tracking these time for an object can be disabled by calling
>> H5Pset_obj_track_times() with the 'track_times' parameter set to FALSE.
>>
>>
>>
>>
>>
>>
>
>