On Thu, 15 Feb 2007, John Taylor wrote:
>> IP (sockets) on the other hand, were designed for this purpose.
>> A simple solution is to provide a well-known port for discovery
>> (basically just a simple keyword-value cache; back it up with an
>> environment variable or whatever to config the address)), and hand-off
>> to dynamically allocated ports for session stuff. This can all be done
>> at the protocol level without an API, is universally available, and is
>> really not much more complex than using a file. Probably less complex,
>> when you consider the subtle issues that files have for this purpose.
>
> I'd be interested to know how much easier or harder it would be to use IP
> from relatively primitive programming environments such as IDL (that's not a
> slur on IDL...it's very sophisticated in other ways).
Well, we are after all talking about messaging software right? Any system/app/language using this will already have had to figure out how to talk to a socket.
> One question I have is
> what would happen on a multiuser machine? Would you need some system process
> running on the one shared well-known port?
Not necessarily, but you could. The same mechanism could be set up either way. In either case the idea is one would use this only to provide a simple discovery mechanism, to bootstrap things up, then hand off to other facilities. Having something which at the most basic level can be accessed by multiple accounts could be a useful thing it itself, as sometimes resources which need to discover each other and communicate are running under separate accounts.
Clearly there are issues which need further thought, but the point is to explore alternatives to the use of file-based mechanisms for simple runtime discovery in a LAN type environment.