Higher-level Naming

Machine addresses provide unique identifiers for interfaces within one machine, but a higher-level naming scheme is required for several reasons, for instance:

• We want to refer to entities in distributed systems, which have rather different naming requirements.
• On a single machine, programs do not know addresses of other components when they are linked. These must be determined using other names at load time and run time.
• Human-readable names are required for users, managers configuring the system or examining it remotely, and programmers building and debugging it.

The important thing to realise is that these naming issues are completely orthogonal to the idea of a single address space, and so almost any existing name space scheme can be used. Our approach is currently based on a directed graph of contexts referred to with pathnames, together with a simplified version of the ANSA Trader's constraint language ([]). This allows us a lot of expressive power in the name space when we need it (and extends naturally to the distributed case), but in well-known contexts with few or no constraints name lookup can be extremely fast.