Linked by Thom Holwerda on Mon 30th Jan 2012 20:39 UTC
General Unix Finally something really interesting to talk about. If you've used UNIX or any of its derivatives, you've probably wondered why there's /bin, /sbin, /usr/bin, /usr/sbin in the file system. You may even have a rationalisation for the existence of each and every one of these directories. The thing is, though - all these rationalisations were thought up after these directories were created. As it turns out, the real reasoning is pretty damn straightforward.
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RE[6]: We are stuck in the past.
by axilmar on Fri 3rd Feb 2012 12:27 UTC in reply to "RE[5]: We are stuck in the past."
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As I said before, metadata. Or maybe media information from something like 'mediainfo'.

It's not metadata. It's data. And it's not only media that have useful data.

Nor should it be. Wrong level to have it.

Yes it should. There should be a standard for it, to allow applications to interoperate at data level.

Not quite, but it's not really hierarchical either, not with links, it's more of a network. Still easy to argue is a database of a form.

You can't run queries on a filesystem regarding the data inside the files, and therefore it is not a database.

The case in question is meta data

Nope. The discussion is about information management, not metadata only.

the tool 'extract' sticks the meta data in a set structure out to stdout.

The schema of the information output cannot be queried at runtime.

With that, find and grep, you could write a "query" that find all jpegs that where taken with a certain camera.

But not all jpegs taken on a certain afternoon, or within a specific time period, or with multiple cameras or users, or many other things.

Plenty of programs that build custom indexs/database of meta data for this kind of purpose

If this functionality was supported out of the box, these programs would be redundant.

Example please. Windows WMI certainly hasn't convinced me.

Almost every application has a layer of data input/output from/to files. This layer would be redundant if databases were supported out of the box.

What parts exactly? Not all fileformats are like that, many are just blobs

Nope. All file formats have an internal structure, otherwise they could be read after they were written.

What about a video, once you dismiss the metadata stuff, how are you going to store the stream?

As an array of frames, and each frame being an array of pixels.

On their own one is likely meaningless, and won't have anything in it you can search.

Nope. One can search for a particular scene, employing pattern matching with another picture, or even a hand-drawn one, for example.

Many filesystem do offer transactions

Many, but none of the major ones, as far as I know.

The SQLite site has some a doc on how they do it generically

SqlLite achieves transactions through various mechanisms, as described in the paper. These mechanisms are based on the functionality provided by filesystems, but the filesystems themselves do not have the concept of transaction.

In order to enable transactions in another application, one has to rewrite the same SqlLite mechanism.

Pretty much every OS has a notification system for file or folder changes.

But these notification mechanisms are not compatible with each other, many O/Ses don't even have such notification mechanisms, these notification mechanisms don't work over the internet, and applications cannot be notified about what exactly changed inside a file.

Found this, sounds like what you want:

Not bad. It's a step in the right direction.

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