From: Charles Lindsey (chl@clw.cs.man.ac.uk)
Date: Thu Sep 06 2001 - 09:08:40 CDT
In <tLSJhXHR2il7EwZP@on-the-train.demon.co.uk> "Clive D. W. Feather" <clive@on-the-train.demon.co.uk> writes:
>In message <200109041154.MAA01837@clw.cs.man.ac.uk>, Charles Lindsey
><chl@clw.cs.man.ac.uk> writes
>>I think the main issues with regard to cancels are concerned with
>>multiple cancels.
>I think this is something we *should* solve in the main document, right
>now. Whether it's a block cancel or a NOCEM, don't worry about security
>- it should and will use the same security mechanism as a single cancel
>does.
Well let us at least gather some issues together regarding multiple cancels.
Q1. Is is the case that typical spews and spams get posted over relatively
short timescales, so that the canceller/nocemer is in a position to grab
the whole batch and deal with it as a single entity?
My observation of some recent Hipcrime episodes seems to indicate that he
tended to put out a large spew, taking maybe half an hour. And then he
took some time off while he morphed to a slightly different spew, and then
sent that one out (though sometimes he did seem to have two versions on the
go simultaneously).
Q2. Do cancellers try to catch a spew in real time, issuing cancels as
fast as articles arrive (so that hopefully they arrive at sites before the
cancelled articles)? Looking at some recent cancels by Andrew, it seemed
that the cancel was issued typically one hour to three hours later than
the spam, which does not seem like a real time operation.
Q3 Are Nocems typically issued at the same time as cancels, or are they
usually saved up for largish batches?
Depending on the answers to these questions, one can see whether issuing
multiple cancels in one go would help.
Note that multiple cancels would surely be essential if one were to sign
them digitally, since generating/checking a signatue is CPU-intensive, and
hence is only viable if you can incorporate a large number of cancels
within the one signature.
-- Charles H. Lindsey ---------At Home, doing my own thing------------------------ Tel: +44 161 436 6131 Fax: +44 161 436 6133 Web: http://www.cs.man.ac.uk/~chl Email: chl@clw.cs.man.ac.uk Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K. PGP: 2C15F1A9 Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5