Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!ub!kensmith From: kensmith@cs.Buffalo.EDU (Ken Smith) Newsgroups: comp.protocols.nfs Subject: Re: Novice NFS questions Message-ID: <67431@eerie.acsu.Buffalo.EDU> Date: 26 Mar 91 14:09:37 GMT References: <945@dri500.dri.nl> <1991Mar26.073554.2230@thunder.mcrcim.mcgill.edu> Sender: news@acsu.Buffalo.EDU Organization: State University of New York at Buffalo/Comp Sci Lines: 35 Nntp-Posting-Host: milo.cs.buffalo.edu Originator: kensmith@milo.cs.Buffalo.EDU In article <1991Mar26.073554.2230@thunder.mcrcim.mcgill.edu>, mouse@thunder.mcrcim.mcgill.edu (der Mouse) writes: |> |> |> Just a few minor things to add for the curious... Allowing you to really access a remote device rather than having all devices treated as local is the only thing I've seen that RFS (AT&T's version of remote file sharing) lets you do that NFS does not. However the reason that you get this capability is that each time you try and access a remote partition under RFS it packs up the request at the system call level and ships it off to the server. The system call gets executed on the server. This means, as far as I can tell, you could never have a completely diskless machine using RFS because it could never access its own keyboard, serial port, etc. Anyway I got my masters by extending SunOS so that you could access remote devices as if they were local. Basically it involved making a new file type called a ``remlink'' that looked sort of like a symbolic link but stashed enough information in it to define a server as well as a pathname. When this was opened a new set of vnodeops handled connecting to a daemon on the server. The daemon handled requests like opening the device, read/write, ioctl, etc. This system was designed to run alongside NFS, providing extra services that NFS couldn't (and shouldn't since as far as I can tell providing that service would violate most of NFS's basic design goals, like transparent crash recovery). -- Ken Smith internet: kensmith@cs.buffalo.edu "The seaweed is always greener in bitnet: kensmith@sunybcs somebody else's lake." -Sebastian