On Tuesday 11 June 2002 06:13, Daran wrote: [... snip ... interesting but non-contentious]
> Very noticable is the proportion of exponents - in all three ranges - which > are not getting a stage two effort at all. 26 out the 85 exponents between > 7950000 and 796000, 24 out of 54 between 15500000 and 15505000, 35 out of > 57 between 33219000 and 33223000. I do not believe that large numbers of > P4 systems are being shipped with just 8MB of RAM! This is true. However the philosophy of the project, correctly in my view, is that the software should not cause noticeable deterioration in the performance of a system when it is being run in the background to normal work. If the software were to allow itself to use a substantial portion of the system memory (even temporarily during P-1 stage 2 only), anyone using a system monitoring tool to find out why the system performance had dropped would no doubt discover a process with a large working set, blame it (correctly), and the project would lose a participant. Or possibly many participants, depending on how far and by what route the news spreads. Yes, I know it's possible to tinker with the different day/night memory allowances, even to schedule the program not to run at times when it might get in the way. But these sorts of things can only be configured locally; working times vary, as does the convention as to whether the system clock is set to local time or GMT/UTC. The default has to be "safe"; IMO the current default memory allowance of 8MB is entirely reasonable, even though it causes P-1 to run stage 1 only for any realistic assignment, and even though _new_ systems are usually delivered with at least 256 MB RAM. Running P-1 on a "10 million digit" exponent requires in excess of 64 MB memory to be allocated in order to run stage 2 at all. That's a lot to ask as a default! BTW you may have noticed that, when a system runs P-1 stage 1 only, it runs to a higher limit than the stage 1 limit used for neighbouring exponents which have had a P-1 run of both stages. The P-1 factoring run by these systems is still useful to the project! Regards Brian Beesley _________________________________________________________________________ Unsubscribe & list info -- http://www.ndatech.com/mersenne/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
