If you require more controls on file permissions, ACL (a.k.a Access Control Lists) might be a nice choice. ACL goes beyond normal user-group based permission control and allow setting permissions on per individual user or group basis.

The Journaling Block Device layer (JBD) isn’t ext3 specific.  It was designed to add journaling capabilities to a block device.  The ext3 filesystem code will inform the JBD of modifications it is performing (called a transaction). The journal supports the…