20101113, 20:43  #1 
Jun 2010
Pennsylvania
39F_{16} Posts 
'Total time' value in Factor4
Hello,
I just (finally) completed running an exponent to 73 bits, and I have a question about the time reading that's given at the end. The "Total time" value is given as "414528.281 secs." Supposing that "secs." is seconds, then if I haven't forgotten completely how to do math, that amounts to (414528.281/60) = 6908.8 minutes, or (6908.8/60) = 115.146 hours. That would be less than four full days. But in fact the poor computer was patiently chipping away at this one exponent 24/7 since the first week of October, or close to a month and a half. So the question is  what does that "Total time" value represent? In case it helps to find the answer, that PC (an older model) is running Factor4. Thanks! Rodrigo 
20101113, 23:30  #2  
Oct 2007
London, UK
1299_{10} Posts 
Quote:
But anyway, did you restart the PC and resume from a checkpoint part way through or something? Possibly it only records however long the last run was. Alternatively, perhaps something else on the PC was using most of the CPU time, and factor4 only got to use the CPU for a combined total of 115.147 hours. I also note that the time in seconds multiplied by 10 gives ~48 days, which is approximately a month and a half, maybe that is just a coincidence though. 

20101114, 00:18  #3  
Jun 2010
Pennsylvania
3^{2}×103 Posts 
lavalamp,
LOL! I guess that I have forgotten how to do math  that's less than five days. Quote:
Nothing else was going on on the PC, except for the security software (AV and firewall) and the occasional automatic definitions updates to it. Now, I said that it ran "almost" nonstop, because I did restart the system a couple of times, closing Factor4 and then reloading it using the r switch. Oh, and  come to think of it  we had a brief power outage exactly as long ago as Factor4 reports the "Total time" was! (Thank you, APC.) So the program was not properly shut down. That must be the reason. Maybe Factor4 forgets how long it's been working on an exponent, if it doesn't get closed correctly. Thanks lavalamp  your idea led me to what no doubt is the answer! Rodrigo 

20101114, 00:34  #4 
A Sunny Moo
Aug 2007
USA (GMT5)
3·2,083 Posts 
This is a rather common phenomenon with primecrunching applications. For instance, LLR (a Prime95based program for testing numbers of the form k*b^n+c) similarly only reported time elapsed since the last resume until its 3.8.0 release earlier this year, in which it started keeping track of that in the save file. AFAIK, it is still the only application of its kind to support such a feature.

20101114, 01:13  #5 
Jun 2010
Pennsylvania
3^{2}×103 Posts 
mdettweiler,
That's interesting! So, Factor5 must work like Factor4 in this regard. Not that it's a critical flaw or anything, just an obscure corner of the software to wonder about on a lazy Saturday... Rodrigo Last fiddled with by Rodrigo on 20101114 at 01:13 
20101114, 12:02  #6 
Banned
"Luigi"
Aug 2002
Team Italia
11·433 Posts 
Rodrigo,
mdettwweller and lavalamp are right: the program only records the time elapsed since last restart. Luigi 
20101114, 16:41  #7 
Jun 2010
Pennsylvania
3^{2}×103 Posts 
Luigi,
Thanks for confirming! Rodrigo 
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