[QUOTE=Rodrigo;223195]Luigi,

Thank you for the suggestion. OBD is definitely in the running. Even if the ultimate goal is that much further away, knowing that my older machines are completing more tasks in a given time is an attractive option.

How would I get OBD work assigned to my PCs?

Rodrigo[/QUOTE]

1 - Download the program suitable for your platform from [URL="http://www.moregimps.it/billion/download1.php"]here[/URL]
1 - Choose one or more exponents from [URL="http://www.moregimps.it/billion/expo_i.php?id=bit_depth"]here[/URL]
2 - Determine how deep you want trial-factor the Mersenne number (notice that taking it from 63 to 64 bits needs twice the time needed to take it from 62 to 63) making some tests.
3 - Check out the number [URL="http://www.mersenneforum.org/showthread.php?p=223042#post223042"]here[/URL]
4 - Report your results [URL="http://www.mersenneforum.org/showthread.php?p=223166#post223166"]here[/URL]

And

5 - Ask me for whatever question about it. :smile:

[edit]
I'm afraid the actual versions on the website are optimized for core processors. Give them a try and let me know, we have probably to recompile the source code on your platform :sad:

Luigi

Luigi, this is great! You've provided the "complete package." :smile:

I have yet to look at the other steps, but I already have a follow-up question on the first one. On the page where you select the version of the program, which one would you recommend for a lowly P75 and a P233? Basically I'd like to know if there is a reason to choose Factor3_1_Win (the slowest version) instead of, for example, Factor4_Win (and would I choose the SSE2 variety).

In case it makes a difference in the selection, the P75 is running DOS 6.20 and Windows for Workgroups 3.11; while the P233 is running Windows 98 Second Edition.

[edit] Oh, wait -- I just remembered you had an edit that addressed the question of how to select the version. Maybe I should just pick one and see what happens?

Thanks!

Rodrigo

[QUOTE=Rodrigo;223195]Thank you for the suggestion. OBD is definitely in the running. Even if the ultimate goal is that much further away, knowing that my older machines are completing more tasks in a given time is an attractive option.[/QUOTE]

"Even if the ultimate goal is that much further away...

Yeah. Hundreds of years...

I'm not trying to be negative here, but I have to ask what is the point in investing time and energy into something which is truly pointless?

By the time a billion digit P exponent (2^P-1) will be tested we will (hopefully) have quantum computers able to do this kind of work in a tiny fraction of the time our current technology can.

So why burn oil having a P75 work on this?

chalsall,

A pertinent question.

I'm considering OBD largely because I get the impression that if I put the P75 on GIMPS there will be grumbling about how it's slowing down the train. Moreover, it sounds like over at OBD it can accomplish particular tasks quicker than in the GIMPS "mainstream."

But why even bother putting the P75 online? Let me backtrack some here.

We might call it a kind of virtuous circle. When I first heard of GIMPS, and before knowing any of the details, I got really excited about the prospect of putting my older PCs back in service doing something useful instead of gathering dust.

That prospect then motivated me (a) to upgrade those PCs with additional memory and network cards, and (b) to set up a home network so that each of the computers can report in when needed. [B]In the process, I've learned a ton about computing.[/B] So the mere fact of hearing about GIMPS has already had positive external effects, which would not have occurred otherwise.

Now I'd like to make use of this newfound knowledge (completing the circle) by contributing them to GIMPS and/or OBD, the very concept that prompted me to acquire that knowledge in the first place. If I now fail to put them on one or the other of these projects, it will be as if all of that effort and learning had been for naught. What economists call the "psychic value" of the activity will disappear.

I hope I've explained adequately where I'm coming from.

Rodrigo

[QUOTE=Rodrigo;223275]Now I'd like to make use of this newfound knowledge (completing the circle) by contributing them to GIMPS and/or OBD, the very concept that prompted me to acquire that knowledge in the first place. If I now fail to put them on one or the other of these projects, it will be as if all of that effort and learning had been for naught. What economists call the "psychic value" of the activity will disappear.

I hope I've explained adequately where I'm coming from.[/QUOTE]

I appreciate your above.

I hope you et al will appreciate this...

1. I am very pleased that you have learnt from this experience.

2. No teacher expects to be compensated directly from their student's learning.

2.1. A teacher will, however, always hope that their students go on to help and teach others.

3. Your (and many others') slow machines would be much better off being donated to a charity which can route them to those who have no computing resources currently.

3.1. No disrespect intended, but telling the truth -- one of my machines can do in a few minutes what one of your older machines would take days to do -- with *much* less power consumed per work unit.

From this, then, may I please advise you (and possibly others) to...

1. Donate your slow machines to a charity which will see that they end up in the hands of those who need them.

2. Use the knowledge you've gained here to support these (and possibly other) computers; where ever they end up.

2.1. You could still help GIMPS in this case. But only slowly; and while the machine was doing more than consuming energy and creating heat. :smile:

The money you save on your electric bill by not running the older machines would quickly add up to the purchase price of a new machine which would outpace the combined output of your old machines by 10's if not 100's of times and would give you much more work done over the long run.

[quote=chalsall;223281]3.1. No disrespect intended, but telling the truth -- one of my machines can do in a few minutes what one of your older machines would take days to do -- with *much* less power consumed per work unit.
[/quote]

chalsall,

Thank you for the advice. Just one question --

Help me to understand this. My machines are a P-75 :showoff:, a P-233, a PII-400, a P-T4200 (2.00GHz), and a P-E2200(2.20GHz). For the sake of simplicity, let's suppose that all together these five PCs can produce 1.00 units of output for GIMPS. Let's say that the first three account for 0.01 of the total, with the last two contributing 0.99. (The actual proportions don't matter; they could be 0.0001 and 0.9999 and the issue would remain the same.)

I'm no math whiz, but in terms of helping GIMPS to get its work done, I'm not sure how 0.99 units of contributed output might be preferable to 1.00 units of contributed output. (I do understand about the matter of kW per unit of work, but that's not what I'm asking here.)

I do appreciate your taking the time to explain. :smile:

Rodrigo

As far as the saving money aspect is concerned, doing 0.99 units for a year, and then 1.50 units after upgrading will work out to more total work done in the long run. (My 1-year figure is just a wild guess on my part - and this is all assuming you 1) even care about the electricity cost and 2) would put the savings of not running the old machines towards a new one)

As far as GIMPS is concerned, the more work the better, regardless of the cost. However, if you hold out the 0.01 units with the goal of adding 0.50 units in the future, it's better for GIMPS in the long run. I'm sure there's a name for this idea, but I'm no economist. :)

Of course, if money were no object, you could just keep running the old machines AND buy a new one, and end up with 1.51 units of work being done. ;)

[QUOTE=Rodrigo;223286]I'm no math whiz, but in terms of helping GIMPS to get its work done, I'm not sure how 0.99 units of contributed output might be preferable to 1.00 units of contributed output.[/quote]
It isn't preferable for GIMPS -- but it is preferable for you. Don't think that we're saying that the offer of computation is not wanted. Some computation is better than no computation!

However, with technology that old, the cost of electricity is a very real factor to be considered (again, for you). Eventually, it is up to you to make the decision to see if it is worth it or not to run these old computers. However, we just hope that the decision you make is an informed one.

Consider this: if you overclock your two fastest computers by a paltry 25MHz, you would have already accomplished more computation per second than your slowest 3 computers!

[QUOTE=Rodrigo;223286]I'm no math whiz, but in terms of helping GIMPS to get its work done, I'm not sure how 0.99 units of contributed output might be preferable to 1.00 units of contributed output. (I do understand about the matter of kW per unit of work, but that's not what I'm asking here.)[/QUOTE]

You might consider the global impact you're having contributing to GIMPS.

You are consuming energy, and generating heat, while you inefficiently contribute to GIMPS (or any other distributed computing effort) using these ancient machines.

If you're comfortable with that, then fine.

But please know that that energy could probably go a lot further being used elsewhere....

[QUOTE=chalsall;223273]"Even if the ultimate goal is that much further away...

Yeah. Hundreds of years...

I'm not trying to be negative here, but I have to ask what is the point in investing time and energy into something which is truly pointless?

By the time a billion digit P exponent (2^P-1) will be tested we will (hopefully) have quantum computers able to do this kind of work in a tiny fraction of the time our current technology can.

So why burn oil having a P75 work on this?[/QUOTE]

What about algorithm enhancement? :smile:

Thank to OBD, we discovered lots of low-hanging fruits (factors) of billion digits Mersenne numbers. Thank to Oliver (TheJudger) we now have a Mersenne factoring program that can reach 95 bit factors. But reaching 95 bits depth even on OBD numbers would be a tough task. Luckily enough, our previous nonsensical work provided him with factors that, multiplied together, could simulate a 90-95 bit huge factor to test his program.

Nothing of the previous paragraph would have happened without slow computers thrown into OBD...

Luigi