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Quincey Koziol <koziol@xxxxxxxxxxxxx> writes: > Hi Mike, > >> This question came up today at the NASA briefing, when we were talking >> about the netCDF 4 project. There was a weak but immediate and negative >> reaction to using time as a proxy for creation order. The reason given was >> that many applications would want to use the creation time as an attribute, >> but that the times used would not necessarily give the same ordering as >> creation time because different times might be relative to different time >> zones. I have a feeling there were other cases, given the reaction people >> had. >> >> Of course this could only happen if people were allowed to change the >> "creation time." And one could also argue that creation time is a >> different attribute -- it's the time the link was created, not the time the >> data was collected. But I have a feeling this would just lead to confusion. >> >> So at best, I think there is concern that this could led to confusion. I >> tend to agree. > > Ok, I think we've heard enough customer push-back on this that we ought to > provide both options and allow people to choose which they'd like. Here's a > list of the fields that I'm planning on storing on storing for each link: > - Name (indexable, must be unique, modifiable) > - Creation time (indexable, may be non-unique, modifiable) > - Creation order (indexable, unique, monotonicly increasing, > non-modifiable) > - Character set (i.e. ASCII, UTF-8, etc.) (non-indexable?, non-unique, > modifiable) > - Object address/link target (for hard/soft links) (non-indexable, may be > non-unique (for multiple links to same object), modifiable?) > > Applications can determine which of the three indexable fields they'd like > to have an index maintained for with a group creation property. They will > choose an index for iteration, etc. with a group access property. > > Quincey Thanks Quincey! I think that will work better for netCDF-4. Ed -- Ed Hartnett -- ed@xxxxxxxxxxxxxxxx