[mdlug] The new "surface" computer

Daud Lee Lambert as4109 at wayne.edu
Sat Aug 4 20:44:36 EDT 2007


----- Original Message ----- 
From: "Robert Adkins" <radkins at impelind.com>
To: "MDLUG's Main discussion list" <mdlug at mdlug.org>
>     Alternative Data Streams is not the same as Metadata.
>
>     Metadata is part of the normal file and can be used to input things
> that the OS can use to determine what kind of file it is looking at.
> This is what Apple did for years with the Mac, even if it had something
> similar to ADS, as I understand it, this isn't what the Metadata is.
>
>     Metadata is like a "header" in a file. In a way this metadata is
> similar to what you see in the first few lines of virtually every single
> Binary format CAD/CAM file. In the first few lines there is plain text
> information telling you the CAD System the file was generated from, [...]

There are many file formats that consist of metadata followed by
more-simply-structured data;  but the metadata can also be the information
stored in the file-system about the file.  On some filesystems,  that's only
the name, size and creation-time;  on others, it includes all sorts of
things.

>     Anyway, what got me thinking about this is some stuff I was reading
> regarding a need for people to start using the metadata features of file
> systems (I believe even FAT32 can do this) to get away from the finite
> combination of the three letter extension. This was talked up regarding
> the metadata capabilities of Linux and certain Desktop Environments.

VFAT is a crazy hack on top of the FAT directory-structure that only
supports longer names using Unicode characters.  No form of FAT supports ADS
or anything similar natively.

It's certainly possible to store metadata in another file,  or in a shared
database-file,  or in a lot of other places...

Linux has Posix Extended Attributes on some filesystems,  which are similar
to this.  If I remember correctly,  Samba has some way of supporting
alternate streams even on a vanilla Unix filesystem,  just as it supports
case insensitivity even on a case-sensitive filesystem.

The ResiserFS v4 design document has a good discussion of how everything can
be reduced to just files and directories:

http://www.namesys.com/v4/v4.html#design_flaws_details





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