Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!athena.mit.edu!jik From: jik@athena.mit.edu (Jonathan I. Kamens) Newsgroups: comp.unix.wizards Subject: Re: NFS and UFS Mounting on a non-empty directory Keywords: Frustration, Yellow Pages Message-ID: <12921@bloom-beacon.MIT.EDU> Date: 23 Jul 89 16:58:52 GMT References: <2339@orion.cf.uci.edu> Sender: daemon@bloom-beacon.MIT.EDU Reply-To: jik@athena.mit.edu (Jonathan I. Kamens) Distribution: na Organization: Massachusetts Institute of Technology Lines: 32 In article <2339@orion.cf.uci.edu> Guy Cardwell writes: >The big question is... is the concept of NFS mounting on a non-empty >directory well defined??? Could I place a default passwd file in a >directory, and later mount the NFS one on top of it safely.. (would >the results be the same between various NFS implementations.... ie.. >SUN 4.0, DEC Ultrix, HP UX, Xenix, IBM A/IX) (yes, we have at least >one of each). Yes, the concept of mounting over a non-empty directory is well-defined, and has been discussed here recently, in reference to having a /tmp or /usr/tmp on the root during boot time, and then mounting something over it via NFS in order to have more space in it during multi-user operation. Our (4.3BSD) man page for mount(2) says the following: >DESCRIPTION > mount attaches a file system to a directory. After a suc- > cessful return, references to directory dir will refer to > the root directory on the newly mounted file system. Dir is > a pointer to a null-terminated string containing a path > name. Dir must exist already, and must be a directory. Its ^^^ > old contents are inaccessible while the file system is ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > mounted. ^^^^^^^ Jonathan Kamens USnail: MIT Project Athena 432 S. Rose Blvd. jik@Athena.MIT.EDU Akron, OH 44320 Office: 617-253-4261 Home: 216-869-6432 Brought to you by Super Global Mega Corp .com