On 18 Jun 00, at 21:25, Larry Murray wrote:
> I thought had occurred to me with this prize that is being offered. what
> happens if you work on a number for 6 months and then it is re-assigned to
> a person with a faster computer and their computer finishes the
> computation first and it is found to be a prime. Who is entitled to the
> Prize? Does that mean if you have A slower 550mhz computer don't bother
> testing a 10 million number? If you do make sure you always check in
> because it can be taken from you? On the same subject what-if you're the
> person the number is reassigned to and you work on a number for 6
> months to find that it was a reassignment and it was found to be
> prime...I think with the longer testing time of the 10 million digit
> numbers the time between reassignment of those numbers should be much
> longer. I personally have been running 3 ten million digit numbers on
> Pentium 550's since September of 1999 and hardly
> ever even bother with the computers that are running them I have strictly
> devoted them to the mersenne project...ANYWAY ITS SOMETHING TO THINK
> ABOUT--TAKE CARE ALL
You have to check in occasionally to keep the assignment. This is
entirely reasonable since some people are bound to "default" without
bothering to return the assignment.
If it's too inconvenient to connect the actual systems to allow them
to check in, you can use the PrimeNet Manual Testing page to check
assignments in manually in order to prevent them from expiring. Since
you can "extend" an assignment for up to 120 days (plus the 60 day
grace period) you should only need to do this two or three times
during the run.
If you run assignments which aren't given to you by PrimeNet, or
continue to work on assignments which have been reallocated due to
your failure to check them in occasionally, I don't think you should
be entitled to a share of any prize. However it looks as though,
according to the EFF rules (which I haven't looked at for a while),
the first discovery reported to EFF takes precedence.
Since the expected return on testing numbers in the 10 million digit
range is of the order of 40 cents / PIII-550 year, I doubt too many
people are participating simply because of the existence of the prize
... ?
Also, note that it's entirely possible that the EFF prize will be won
by someone working on non-Mersenne numbers using entirely different
software and/or hardware.
BTW for QA reasons I am already working on a double-check of a 10
million digit number before the first test is completed. I will make
damn sure that the "official" owner of the assignment reports the
final result, abandons or allows the assignment to expire before I
report the result myself. (And the "official" owner knew this before
I started!)
Personally, and bearing in mind that there are a lot of much smaller
exponents which still require testing, I consider a standard PC
running a PIII-550 to be inadequate for running 10 million digit
exponents. I'm using an Athlon 650, which is about 35% faster, and I
have a system (self-)built for reliability rather than down to a
price. However, GOOD LUCK to all those who do chance their arm!
Regards
Brian Beesley
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