IRC, freenode, #hurd, 2012-04-20

<Tekk_> what are the extensions to ext2?
<Tekk_> that hurd uses
<braunr> tha ability to store passive translator command lines in the
<braunr> the*
<antrik> well, also a fourth set of permission bits, and an "author" field
<braunr> right
<antrik> both very obscure features that better never existed...

The fourth set of permission bits is for unknown users.

In order to take advantage of these features, the owner/creator of the partition must be set to hurd. mke2fs, unless specifically overridden on the command line (-o hurd, for example), will set the default to whatever system it is running on. At least the root filesystem must be of hurd type, as it has to store various passive translator settings. Even if a file system is not of the native type, others may still use it; they just may not be able to use certain extensions.