On Tuesday 22 October 2002 19:09, Gordon Bower wrote:
> [... snip ...]
> Does anyone have any suggestions for how to stop a runaway copy of
> v18? Perhaps in a few weeks the server can be updated to return an "out of
> exponents" error to v18 instead of offering it an assignment it can't
> handle?

This is not trivial - if you do this then a "broken" client will probably 
request another assignment immediately - thus trapping the client and the 
server into a vicious circle. Whilst the client can go hang for all anyone 
else cares, the effects on the server would probably be much the same as 
handing out an "unacceptable" assignment.

Other people have mentioned the possibility of "automatically" disengaging or 
updating the client. I have very serious reservations about this; the problem 
is that it leaves the system hosting the client wide open to use of the 
mechanism for malicious purposes, e.g. "updating" to a client containing a 
trojan or switching it to a different project, or attacking a user by 
disengaging his systems so that you can leapfrog him in the league tables. 

I'm afraid that I would have to withdraw my systems from the project, and 
recommend that other people did the same, if any such capability was added to 
the client.

Given that the server can tell the difference between a v18 client and a 
later one, would it not make most sense to have the server assign a LL test 
on the _highest_ unallocated exponent which v18 can handle if a v18 client 
asks for a factoring assignment and none suitable are available. This action 
would effectively remove the client from the loop for a while (probably a few 
months, given that most v18 clients will be running on slowish systems), 
thereby alleviating the load on the server, and buying time to contact the 
system administrator - when this is still relevant, of course. And some 
useful work may still be completed, eventually!

Regards
Brian Beesley
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