Network application design

The original question sounds like a take-home exam question one might expect in a distributed computing clbutt like the one I took a few years ago. I seem to recall a Byzantine Generals voting problem from the text that I think is similar to this problem.

I'll second that it is not possible to transfer over the internet and guarantee all-or-none delivery within a second. If one packet gets lost to one or two of the destination hosts, it will take well over a second to be certain everything is coherent.

I'll also second that the only hope is to separate the file transfer and file activation steps. Once the sender has verified that all three destinations have received the file (without corruption), then it could instruct the destination hosts to activate the file. Even there, you have to handle the possibility that the instruction to activate the file might get to some but not all of the destination hosts. It might be possible to use a two-step commit scheme as is used in distributed transaction-based database systems.

Say, are you trying to solve the problem Yahoo Finance seems to have that a headline link will show up before the story itself is actually available? 1-2 :-)

-- Robert Riches (Yes, that is one of my email addresses.)