[RC5] Wheres the blocks?

jmv16 at cornell.edu jmv16 at cornell.edu
Sun Jan 10 00:22:48 EST 1999

On Fri, 8 Jan 1999, Eric Gindrup wrote:

>      Recycling is not a bad thing.  Suppose there were one block and a 
>      bunch of clients.  The fastest way to get that block done is to 
>      assign it to all the clients.  The first client to report it back 
>      "wins".  The same is true if there are more than one block.
>      The trouble is reassigning blocks when there are unassigned blocks 
>      left.  Then duplicated work is definitely wasted.  The dupe work 
>      would have been more profitably used to crack untouched blocks.

Is there any way we can get the clients to do a "Is this block already 
completed?" check on all the blocks in the buffer every time they 
connect?  That would at least somewhat alleviate the problems caused by 
people with big input buffers having to do work that may have already 
been redistributed and completed.

Unfortunately, I expect that would cause too much traffic though.  I only
see one similar but less bandwidth-comsuming option:  to have the client
attempt the above status-check (only if a connection is available,
obviously) on the block it is about to begin processing.  The trouble is
that a client which is always online should have a very small buffer to
begin with and thus doesn't gain from the above plan.  And a machine that
is only going to get one communication with the server to download a whole
bunch of blocks before going offline until the next update doesn't benefit
either, since it can't get at the server to verify the status of anything
while offline.  So the only thing that the second plan really does is help
people who expect intermitant connections (for example, a laptop that
might be connected to the network all evening but in mobile use during the
day) and don't want the hassle of increasing buffer size just before going

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