Open Stack

On Mon, Feb 28, 2011 at 10:45 PM, Jay Pipes <jaypipes at gmail.com> wrote:
> for those of a like-minded curiosity about these things. From the
> wikipedia article on this same subject:
>
> "The term Metadata is an ambiguous term which is used for two
> fundamentally different concepts (Types). Although a trite expression
> "data about data" is often used, it does not apply to both in the same
> way. Structural metadata, the design and specification of data
> structures, cannot be about data, because at design time the
> application contains no data. In this case the correct description
> would be "data about the containers of data". Descriptive metadata on
> the other hand, is about individual instances of application data, the
> data content. In this case, a useful description (resulting in a
> disambiguating neologism) would be "data about data contents" or
> "content about content" thus Metacontent. Descriptive, Guide and the
> NISO concept of Administrative metadata are all subtypes of
> metacontent."

And for those wondering why the Glance project uses the term
"metadata" to describe data about the image, we, too, have a similar
terminology problem:

We delineate between the image *data*, which is the raw image file
itself, and image *metadata*, which is really data about the image
(like disk format, status, etc). To make matters worse, we have the
concept of image *properties* which are free-form key/value pairs
attached to the image.

So, neither Glance nor Nova uses the term *metadata* properly, for
what it's worth :)

-jay