Re: tarfs implementation

[Tobin Fricke]

On Thu, 21 Mar 2002 help-hurd-request@gnu.org wrote:

> Perhaps a new archive format should be developed to deal with The HURD.  This
> does not necessarily preclude developing extensions to tar or other incumbent
> formats but rather it could speed up the availability of a working backup

The Linux "access control list" (acl) and "extended attribute" (ea) people
have extended the ext2fs format to support extended attributes --
name/value pairs associated with files. (And the ACL's are stored in EA's)

I was just thinking that perhaps it might be wise to coordinate them,
since 1) the EA mechanism can probably encapsulate the functionality
required by HURD... ie, we could use the same or similar archive formats
and 2) it would be nice if the HURD ext2fs extensions and the EA ext2fs
extensions were not incompatible.

They are using the 'pax' archive format, which, as Jeroen Dekkers pointed
out, supports the extensions we need.

(I haven't used the HURD enough to know how well this fits in with the
HURD philosophy, but it might be nice to have EA and ACL functionality on
the HURD as well.  POSIX ACL's allow one to specify access semantics much
richer than just user/group/other; and EA's are nice because you can
associate metadata (like, for example "character set" or "mime type") with
files.  If we were to integrate support for EA's and ACL's at this early
stage of the game then it's more probable that they would be more widely
used, since people adopting the HURD might see them as part of the HURD
philosophy.)

Anyway, the web page with all the info on Linux EA'a and ACL's is

        http://acl.bestbits.at/

There's a mailing list:

        http://acl.bestbits.at/mailman/listinfo/acl-devel

-- tobin