[RC5] Suggestion for when we Recycle Keys

Jim C. Nasby jim at nasby.net
Mon Jan 11 21:50:23 EST 1999


"Robert A. Rosenberg" wrote:

> <snip>
> Once you start to recycle, you start working on the reissued blocks in the
> reverse order to that being used by the original owner. Thus you do not
> duplicate his/her work until you overlap. As an example User A is issued
> Blocks X to X+9 and when he is up to X+5, User B is issued X to X+9 (as a
> recyle). If User B starts at X (in lieu of X+9), he is spinning his wheels
> doing no productive work until he gets to X+5 (or where-ever A is now in
> his checking). By starting at X+9 and working back to X, there will be some
> productive checking before there is any overlap.
>

This would actually make matters worse. The blocks are returned in a _generally_
linear fasion, so what you are proposing would increase duplication greatly. It
takes some time to work through the entire keyspace, and as long as people aren't
sitting there with huge buffers, we'll be better just starting from the beginning.
If they don't, we're in trouble no matter what. Plus, I'm pretty confident that
the coders aren't going to consider any major changes to the code unless there's
some pretty significant payoff, as there was with the quickstart code. If you'd
seen how much work went into that relativly minor change by so many different
people, you'd understand.

Moo!
dB!

>
> >
> >>
> >> ALSO, I think that when I turn in Checked Keys (or ask for more) that
> >> my CURRENT set of assigned keys be sent to the Server for checking
> >> against the list of already checked keys. If I have been assigned
> >> keys that have been checked (due to recycling), then MY IN-Box copy
> >> should be pruned of those and my IN-box optionally updated with
> >> replacements for the deleted blocks. This prevents useless checking
> >> and focuses on new keys (ie: Those that have not yet been turned in
> >> as checked). Yes I will still be working on keys that others are
> >> checking but I insure that when I select such a key AFTER having
> >> checked in, that it will be one that has NOT YET been reported as
> >> checked as of my check-in time.
> >>
> >
> >For RC5, this would serve no purpose. Since we have subspaces in RC5, we can
> >allow a subspace to lie dormant for a period of time before we recycle it, so
> >we loose very little processing power. For DES, we don't have that luxury, so
> >we loose work to duplication when we do a recycle. So, for DES, it is
> >desireable not to have to recycle.
> >
> >Unfortunatly, it would take a large effort to enable our network to accept
> >blocks back. The master, proxies, personal proxies, and clients would all
> >require major changes.
> >
>
> This was more a suggestion for a new feature to be considered. It can be
> implemented on a gradual basis. First the Servers (to support it). Then
> Clients and Proxies can take advantage of the functionality. All that is
> needed on the Server side is to accept a list of Blocks and return the list
> marked "Checked" or "Not Checked" for each Block. The Client/Proxy then
> checks the returned list and prunes (ie: Throws away) from the IN-Buffer
> any that are marked "CHECKED". It can then do a Fetch to refresh its
> buffer. No Blocks are being returned to the server for reissuing (that was
> a different request) so all that is needed is the status support.
>
> >The best solution is too minimize the amount of DES blocks that might be
> >lost... in other words, keep your buffers as small as possible.
> >
> >>
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> >
> >--
> >Jim C. Nasby (aka Decibel!)                                  /^\
> >jim at nasby.net                                               /___\
> >Freelance lighting designer and database developer         /  |  \
> >Member: Triangle Fraternity, Sports Car Club of America   /___|___\
> >
> >Give your computer some brain-candy! http://www.distributed.net Team #1828
> >
> >
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--
Jim C. Nasby (aka Decibel!)                                  /^\
jim at nasby.net                                               /___\
Freelance lighting designer and database developer         /  |  \
Member: Triangle Fraternity, Sports Car Club of America   /___|___\

Give your computer some brain-candy! http://www.distributed.net Team #1828


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