On 8/20/07, Tom Lieber <[EMAIL PROTECTED]> wrote: > On 8/20/07, Francisco J Ballesteros <[EMAIL PROTECTED]> wrote:
> If the problem is stuffing data into a file that was never meant to be > in the file, attributes are a solution. After all, you quote from jsnx > did say, "But where do the oddball intermediaries put their metadata? > ... [They] can't very well stuff album art into your .mp3 files" (or > something like that...). While I don't give a damn about files being directories, I pretty much like Extended Attributes or NTFS files (in NTFS, file is something different than in *nix-like FS or FAT). While I don't like stuffing "persistent" data into EA's (like album art data, icons or similar things), they are fairly useful from system daemon perspective. Since you want examples, I'll give those that I know: * in XFS, several tools use EA's to assign attributes like "DO NOT DUMP" or hierarchical file management data. This data *should* be discarded by normal tools (since cp is creating a new file, and mv only modifes directories but not i-node's EAs) and are of interest only to those system daemons * (IIRC) Beagle daemon uses extended attributes to track files that were scanned and are not modified - they contain part of it's detected metadata, hash and DB pointer * NTFS discards the Unix concept of a file entirely - what was shown before as trouble with Alternate Data Streams is in fact trouble of keeping backward compatibility (Internally, NT doesn't have drive letters or any of the DOS stuff). A File in NTFS is a MFT entry with a bunch of attributes. Those attributes have several types/names defined, like DATA for file contents, one for keeping filename (for which there are three namespaces: DOS8.3, Windows, POSIX), one for legacy DOS attributes (used by the official, backward compatible API), one for security data, and others used mostly by system daemons (Although NT5+ explorer uses one to hold various comments about files. Rarely used by people I think). I especially like the NTFS implementation, because it allows to use NTFS for most Operating Systems without modifying internal structure, while making it easy to add "compatibility layer" As for things that need to work with cp/mv/others, I suggest making better file formats or adding metadata in different file. It's not the smartest use of Extended Attributes/NTFS attributes :-) > -- > Tom Lieber > http://AllTom.com/ > -- Paul Lasek
