Messages in this thread | | | Date | Thu, 26 Aug 2004 12:54:05 +0200 | From | Wichert Akkerman <> | Subject | Re: silent semantic changes with reiser4 |
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Previously Spam wrote: > Because having user space tools and code will make it not work with > everything. Keeping stuff in the kernel should make the new features > transparent to the applications.
But having it in the kernel has the same problem. If you read the Solaris documentation you will see that a bunch of utilties had to get a new commandline option to be able to access the metadata and a special utility was added for other applications. If you look at windows you will see that you need to use a filename like <realfilename>:<streamname>:$DATA (which obviously does not work for single-character filenames).
Ignoring samba for a bit which just needs streams to stay compatible with windows I see few reasons for using streams:
* files are more complex these days and tend to include multiple different things: images with thumbnails and exif data, 'office' documents containing both text and images
* standard way to add common metadata to a file which can be used for searching tools (author, copyright, keywords, etc.)
But both can already be done in userland (modern image formats can store thumbnails and exif data internally, applications use tar or zip-like files for documents, etc.). The metadata part is a lot more complicated as well since the behaviour of attributes might need to be complex: if I change an image using an application that is not stream-aware, what should happen to its thumbnail?
The only common benefits I can see are standardisation and optimization: instead of every file format or application defining a way to specify metadata for a file you get a common API defined by the OS (but you'll still need to standardize on attribute names and formats, so plenty of room that will still not help), and instead of parsing different files or XML streams you can directly access a bit of metadata.
So far I'm not convinced that streams are worth the effort. Not that my opinion is all that relevant here, but still :)
Wichert.
-- Wichert Akkerman <wichert@wiggy.net> It is simple to make things. http://www.wiggy.net/ It is hard to make things simple. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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