Re: silent semantic changes with reiser4

Hans Reiser
2004-08-27T01:04:31Z

Wichert Akkerman wrote:

>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.
>
They did it wrong.

> 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).
>
>
again, they did it wrong. See Rob Pike's "The Hideous Name" for why
that is wrong.

>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.
>
>
>