For those of you not familiar with the No Prime Left Behind project, is covers a good chunk of the k-ranges for Riesel primes (k*2^n-1)--the counterpart to PrimeGrid's Proth Prime Search (k*2^n+1). Since the inception of PrimeGrid's PPS effort, we have enjoyed a friendly rivalry between the two projects and some participant crossover (primarily Lennart, who participates in most of our rally events). You can find more information in our forum at http://www.mersenneforum.org/forumdisplay.php?f=82, and specifically our welcome thread at http://www.mersenneforum.org/showthread.php?t=9887, which while admittedly rather out of date regarding active test ranges and the like, still gives a pretty good idea of what our priorities and philosophy are.
About once every month or two, we hold "rallies", which are much like PrimeGrid's Challenge Series. (I believe our rallies came first, but we don't mind--imitation is the sincerest form of flattery. :-)) This time, the PrimeGrid admin squad has graciously allowed us to announce our rally here as well as the usual places (our own forum and a few team forums). Thanks Lennart for spearheading that! :-)
NPLB is not a BOINC project, so we don't even try to compete with PrimeGrid for #1 on the 5000 Largest Primes list. ;-) Instead we aim for second place, to be the premier non-BOINC prime search project on the web. We use much of the same software that PrimeGrid's off-BOINC Project Staging Area uses--PRPnet and LLRnet for primality testing, and sr(x)sieve for sieving.
This is our first week-long rally; previously we'd never gone longer than 48 hours, so this time we decided to try something different, taking a hint from PrimeGrid where you guys have done week-long challenges with great success. The reasoning was that if you're going to go to all the trouble of switching machines over to our rally server, you may as well make it a week instead of switching back after only two days. :-)
As mentioned above, we're using the same PRPnet software for our rally that PrimeGrid uses in the Project Staging Area. Many of you are therefore already familiar with the PRPnet client, and already have it set up on your machines; if not, you can get the latest version and instructions for using it in the PSA PRPnet thread. The only difference is that instead of PrimeGrid's server= lines as detailed in that thread, you'll need to use this one for NPLB:
A cache size of 2-10 pairs is recommended (though 1 is also OK if you prefer). The tests will be in the vicinty of n=850K-860K during the rally and take about 12-13 minutes on my somewhat modern Core 2 Duo. Note that an LLRnet server is also available in the rally range (and the two will be included equally in the rally totals); I'm guessing most of you guys will use PRPnet since it's used here at PrimeGrid, but more information on our updated LLRnet client (which works at the same speed as PRPnet) and how to use it can be found here. LLRnet users should connect to server noprimeleftbehind.net port 3000.
Any primes you find should be reported as "[your name], NPLB, srsieve, LLR" at the top-5000 website. When you submit your first result to our server, at our next hourly stats update your username will be added to our stats database (see http://www.noprimeleftbehind.net for stats--during the rally the home page will change to an hourly breakdown of all pairs submitted on the rally servers). If you're using PRPnet, then one of the admins will get your email address out of the logs and add it to our database so you will receive automatic email notifications of primes; if you're on LLRnet, you'll need to email one of the admins so we can get you set up for notifications. (I can be reached at firstname.lastname@example.org.) You can also post in our teams thread to be added to the team of your choice (or start one if yours is not yet represented at NPLB).
Last time we had a really close race between PrimeSearchTeam (represented solely by Lennart) and Raiders of the Lost Primes (a conglomeration of NPLB participants similar in concept to PST). PST won by a mere 194 results. We're hoping to reverse that this time around, but we welcome any competition that wants to try for a different outcome. :-) The more, the merrier!
If you have any questions about NPLB or the rally, or are interested in participating, please don't hesitate to post in our official rally thread at mersenneforum.org or here--both places will be monitored by the NPLB admin squad and responded to as quickly as possible. You can also email me at email@example.com to ask questions directly, though please know that I will be out of town in the days just prior to the rally (August 11-12) and will probably not be able to answer emails until late on the 12th.
Hope to see you there!