Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!hp4nl!charon!jack From: jack@cwi.nl (Jack Jansen) Newsgroups: comp.os.misc Subject: Re: What constitutes a good OS? (re: file systems) Message-ID: <2823@charon.cwi.nl> Date: 18 Jan 91 11:55:52 GMT References: <41679@nigel.ee.udel.edu> <1211@cvbnetPrime.COM> <41814@nigel.ee.udel.edu> Sender: news@cwi.nl Lines: 36 >>... >> The message 'dir usr/joe/bin' would go to usr, which would send >> 'dir joe/bin' to joe, which would send 'dir bin' to bin, which would >> return the directory of files in that subdir. >> >> You get the idea so far, I'm sure. >>... > Oh, I like it :-). 'bin' could be a library or archive or tar file, >and could return a 'dir' of it's contents -- like I used to be able to >do on my old CP/M system :->. Been wanting that on a "real" system >for years! This is more-or-less exactly the way things work under Amoeba. I say more-or-less, because there are a few details that differ: 1. The sending of the 'dir' message to 'joe/bin' is not done by the server for 'usr', because this would tie down resources in the usr-server, which is a bad thing. In stead, a pointer to the server for 'joe' is returned to the calling program with the indication that the lookup isn't finished yet. 2. There is an optimalisation that a server will gobble up multiple pathname components if it notices that it can. So, if usr and usr/joe live on the same directory server it will do both lookups. This reduces the number of messages needed for the lookup. 3. The idea of using it for tar files as well can be implemented, but it doesn't happen automatically. You have to provide a server that knows what a tar file looks like and will do the lookups for you. For more information about Amoeba: there are ample papers available in the literature, and the full manuals are available for ftp access. Contact me for addresses. -- -- Een volk dat voor tirannen zwicht | Oral: Jack Jansen zal meer dan lijf en goed verliezen | Internet: jack@cwi.nl dan dooft het licht | Uucp: hp4nl!cwi.nl!jack