From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <6539032d477448b0012d3f61ba04e24f@collyer.net> To: 9fans@cse.psu.edu Subject: Re: [9fans] telnet From: Geoff Collyer In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Fri, 23 Apr 2004 02:56:49 -0700 Topicbox-Message-UUID: 69f4ac92-eacd-11e9-9e20-41e7f4b1d025 /sys/doc/net/net.ms:661,687, reformatted: Several possible solutions were considered and rejected; one deserves more discussion. We could have used a user-level file server to represent the network name space as a Plan 9 file tree. This global naming scheme has been implemented in other distributed systems. The file hierarchy provides paths to directories representing network domains. Each directory contains files representing the names of the machines in that domain; an example might be the path /net/name/usa/edu/mit/ai. Each machine file contains information like the IP address of the machine. We rejected this representation for several reasons. First, it is hard to devise a hierarchy encompassing all representations of the various network addressing schemes in a uniform manner. Datakit and Ethernet address strings have nothing in common. Second, the address of a machine is often only a small part of the information required to connect to a service on the machine. For example, the IP protocols require symbolic service names to be mapped into numeric port numbers, some of which are privileged and hence special. Information of this sort is hard to represent in terms of file operations. Finally, the size and number of the networks being represented burdens users with an unacceptably large amount of information about the organization of the network and its connectivity. In this case the Plan 9 representation of a resource as a file is not appropriate.