(Illustration by Gaich Muramatsu)
> What does "distributed simultaneous group broadcast code" mean? It > sounds like it means "multicast". I assume, though, it provides > some facilities beyond simple IP multicast. Oops, sorry, one more time in English. Mark and others, feel free to jump in and correct me. Ensemble is based on IP multicast. However, under the covers it is a multi-phase commit protocol. It gives you primitives like the following: Message A is guaranteed to be delivered to every recipient, or none of them. You know which happened. All recipients can find out who all the other recipients are, with no race conditions relative to sent messages. Messages A, B, and C are guaranteed to be delivered in ABC order, no matter how the network reorders or drops them. It is multicast, so applications that want to be multicast are efficient. Wouldn't you like to have redundant Coda servers on your LAN, in a self-correcting/voting arrangement? Or distributed not across the LAN, but around the world? (I believe this is true) Recipients listen to the protocol details of a sender. If the sender makes a mistake (because that machine is crashing), one or more of the recipients takes over, declares the sender to be busted, kicks it out of the group, and finishes the protocol to a consistant state. Another member of the League for Programming Freedom (LPF) www.lpf.org ------------------------------------------------------------------------------- Brian Bartholomew - bb_at_wv.com - www.wv.com - Working Version, Cambridge, MAReceived on 1998-02-16 00:50:23