Re: [9fans] telnet

[Geoff Collyer <geoff@collyer.net>]

/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.