Computer isn't mine...

[CuriousKit]

I noticed something very weird a couple of days ago when my "Workstation" computer suddenly got a load of double-check assignments, even though it's not due to receive any work. After checking it out, it seems that my actual "Workstation" computer is still crunching through its jobs and is otherwise working as intended, and all the double-check jobs, which are being processed by the looks of things, belong to a completely different computer.

But here's the thing... that second computer named Workstation isn't mine, and I have no idea where it is physically located or even who it belongs to either. It's listed under my CPU page though.

What should I do about this? Because if those jobs complete, I sense I'll be stealing someone's CPU credit.

Examples:
- One of my actual tasks: 2^69,967,421
- One of the unexpected tasks: 2^43,717,231

[Madpoo]

Originally Posted by CuriousKit

I noticed something very weird a couple of days ago when my "Workstation" computer suddenly got a load of double-check assignments, even though it's not due to receive any work. After checking it out, it seems that my actual "Workstation" computer is still crunching through its jobs and is otherwise working as intended, and all the double-check jobs, which are being processed by the looks of things, belong to a completely different computer.

But here's the thing... that second computer named Workstation isn't mine, and I have no idea where it is physically located or even who it belongs to either. It's listed under my CPU page though.

What should I do about this? Because if those jobs complete, I sense I'll be stealing someone's CPU credit.

Examples:
- One of my actual tasks: 2^69,967,421
- One of the unexpected tasks: 2^43,717,231

Did you accidentally create another instance of Prime95 running in another place on that same machine?

Both of those exponents are indeed assigned to the same user, but the cpu ID's are different... different machines as far as Primenet knows. But a new install on the same machine would create a new unique ID.

Both machines have checked in recently (today)... the one doing the LL test was first seen on April 27 and the machine doing the DC was first seen yesterday.

Let's see... what else could help you... LL machine says it has 16 GB and the DC machine says it has 4 GB ... both are the same speed @ 3.4 GHz.

Older box is running "Windows64,Prime95,v28.7,build 1" and newer one is running "Windows64,Prime95,v28.9,build 2"

Did you update the Prime95 version in place, or did you unzip it to a new directory and start it up separately, by any chance?

Well... probably not. Now that I look at the identifying info for the two machine's CPUs, they report as:
Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz
Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

One thing to keep in mind... someone can run Prime95 and put in whatever user id they want (the actual login id, not the display name that shows up in reports and stuff, which can be different).

Maybe someone accidentally put your login id in... who knows. I didn't see any other users with something similar to yours, or at least similar enough that they might reasonably have mistyped it...

Well, that's all I got. Unless I wanted to crawl through log files and look more, which I don't.

On the bright side, if this was some user accidentally doing it, let them go ahead and keep chugging away and adding credit to your account. They're 4% and 4.1% through their first 2 double-checks... maybe it'll finish a few at least (ETA of June 2)

[CuriousKit]

I definitely haven't added any new computers to my collection. "Shadow", "Satellite" and "Remote" are laptops that I have direct access to and can confirm are all build 2 and running as they should, and "Workstation" is my work computer (which is the only 4-core computer I have) that I remote logged in to in order to verify the processes running.

So it does look like someone who decided to name their computer "Workstation" and their user name "CuriousKit". No idea who though, but whoever it is... thank you!

[GP2]

Originally Posted by Madpoo

One thing to keep in mind... someone can run Prime95 and put in whatever user id they want (the actual login id, not the display name that shows up in reports and stuff, which can be different).

Isn't that a problem for the integrity of the results?

If someone managed to sneak a bad residue into the database, they could self-verify it by stealing the identities of two trusted users. Some top producers turn in several exponents daily and are hardly likely to keep track of them all. If a fraud was discovered decades from now then the wrong person would get the blame.

In this vein I am thinking of this post regarding matching bad residues that were discovered because they had the same shift count (not a fraud but the same user accidentally manually resubmitting the same results.txt lines, once with a very old "S numerical" username and later with an actual name).

I'm also thinking of this other post which mentions the exponent M1048507. The interesting part here is not the fact that Ernst Mayer had a "good" result that was off by one hexadecimal digit, but that "Tom Cage" and "Cornelius Caesar" returned the same bad result.

No dates are available, but that was a result from the very earliest years, surely predating the introduction of the shift count. Could this be a single result accidentally turned in twice by the same person? There are roughly three hundred very low exponents where these two users both turned in a good result, luckily you made sure everything under 2M is triple-checked (except for M958933 for some reason). Or perhaps there was a database glitch when converting from the old PrimeNet server to the new one, or perhaps a rare bug in some very early version of the software...

I am thinking of this post by LaurV, where using the wrong FFT size with an early version of CudaLucas caused a reproducible error in the residue. When exactly were shift counts introduced in Prime95, and can we be sure of all the older residues that were double-checked before that?

[Prime95]

Originally Posted by GP2

When exactly were shift counts introduced in Prime95, and can we be sure of all the older residues that were double-checked before that?

Version 17, I believe. The wavefront was at 4M or so. Note that pre-v17 results are the same as shift count equal to zero. All verified results where prime95 was used for both tests should have at least one result with a non-zero shift count.

[0PolarBearsHere]

You haven't tried running Prime95 on a virtual machine by any chance have you?

[Madpoo]

Originally Posted by GP2

Isn't that a problem for the integrity of the results?

I'm not sure... I don't know if it was always that way... I kind of remember that in older versions of Prime95 you had to put the username *and* password into the configuration to connect to Primenet?

I suppose the risk of having some random stranger submit results in the name of someone else is low enough that it made more sense than having a plain text password in a bunch of configs that you might want to distribute to many machines.

Originally Posted by GP2

...There are roughly three hundred very low exponents where these two users both turned in a good result, luckily you made sure everything under 2M is triple-checked (except for M958933 for some reason). Or perhaps there was a database glitch when converting from the old PrimeNet server to the new one, or perhaps a rare bug in some very early version of the software...

Hmm... that was weird. I had to look and see why I missed that one. Turns out that there are actually *3* results for that exponent, but two are from the same user. Different programs, but shift count=0. One from Prime95 version 11 (whew, that goes back!) and the other labeled simply "Crandall".

It suffers from the same unfortunate LL report "bug" on the website that prevents multiple entries with the same timestamp (or in this case, no timestamp) and same user from appearing more than once as they should. James was actually going to help look into that, although I just realized that the idea I had to fix that wouldn't work in this case since the timestamp is actually NULL. Bummer.

Anyway, maybe I can look again at the exponents below 2M and do a triple-check of anything where only 2 shift-counts exist, instead of just 2 results.

But that one instance shows what George mentioned, that all cases where an exponent was verified with 2 different runs of no-shift-count have been extra verified by a run with a non-zero shift.

Originally Posted by GP2

I am thinking of this post by LaurV, where using the wrong FFT size with an early version of CudaLucas caused a reproducible error in the residue. When exactly were shift counts introduced in Prime95, and can we be sure of all the older residues that were double-checked before that?

If I'm reading LaurV's comments on that problem correctly, it sounds like the error was reproducible, but the incorrect residues were different each time? If there was ever a case where a reproducible error would generate the same (wrong) residue, that would indeed be a problem and makes the case for why we shouldn't accept self-verified results. But in this case, I think it was just a case of the wrong too-small FFT being selected resulting in errors at a certain iteration, at which point the rest of the run was fouled up in their own unique way.

[Spherical Cow]

Originally Posted by CuriousKit

I noticed something very weird a couple of days ago when my "Workstation" computer suddenly got a load of double-check assignments, even though it's not due to receive any work.

Not sure if this has any relevance at all, but a similar thing happened to me in mid-May. Out of the blue, I suddenly got a double-check (38615407) assignment, instead of the usual record level numbers. I checked the setting for "type of work requested" to be sure it was still world record, and that looked fine. It finished quickly, and I didn't give it any additional thought. No change in computers, etc., so I'm not sure what triggered that. Currently my assignments are back to the normal range (74M).

Norm

[ATH]

Originally Posted by Spherical Cow

Not sure if this has any relevance at all, but a similar thing happened to me in mid-May. Out of the blue, I suddenly got a double-check (38615407) assignment, instead of the usual record level numbers. I checked the setting for "type of work requested" to be sure it was still world record, and that looked fine. It finished quickly, and I didn't give it any additional thought. No change in computers, etc., so I'm not sure what triggered that. Currently my assignments are back to the normal range (74M).

Norm

That is due to a recent change which means everyone get 1 DC per year at least unless you opt out here: http://www.mersenne.org/thresholds/

[ATH]

Originally Posted by CuriousKit

I definitely haven't added any new computers to my collection. "Shadow", "Satellite" and "Remote" are laptops that I have direct access to and can confirm are all build 2 and running as they should, and "Workstation" is my work computer (which is the only 4-core computer I have) that I remote logged in to in order to verify the processes running.

So it does look like someone who decided to name their computer "Workstation" and their user name "CuriousKit". No idea who though, but whoever it is... thank you!

As Madpoo says the DC machine appeared for the first time 2 days ago and is running Prime95 28.9 build 2. Did you download the new Prime95 28.9 recently just to test it?

[Madpoo]

Originally Posted by CuriousKit

I definitely haven't added any new computers to my collection. "Shadow", "Satellite" and "Remote" are laptops that I have direct access to and can confirm are all build 2 and running as they should, and "Workstation" is my work computer (which is the only 4-core computer I have) that I remote logged in to in order to verify the processes running.

So it does look like someone who decided to name their computer "Workstation" and their user name "CuriousKit". No idea who though, but whoever it is... thank you!

This intrigued me enough to look at the web log files to see where the hits were coming from.

There are actually 5 different CPUs using your user id on the site, FYI... based on which assignment you said was yours I used the IP address of your most recent updates to determine where your "official" CPU named "workstation" connects from (IP address #1) and the other 4 CPUs all connect from a different spot (IP address #2).

You mentioned the names of some of your other systems "Shadow", "Satellite" and "Remote" and those 3 (plus the other one called "Workstation") are all connecting from that different IP address.

So wherever those other 3 systems are, the 4th one also named "Workstation" lives in the same spot.

Anyway, that should give you some relief... the extra "Workstation" is in the same spot as those other 3 boxes, it's not some random stranger on the intertubes, and it's "birthday" was May 29.

EDIT: Also if it helps, that extra "Workstation" reports itself as having 2 cores, 4 GB RAM, speed of 3.4 GHz even though the CPU model lookup for it says it's "Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz" ... not sure why the speed discrepancy there except that it might get that 3.4 GHz if a config file was copied over from your original "Workstation", but other things like the core count and memory adjusted themselves properly.

Also if it helps, the CPU model, speed, memory is identical to your machine "Remote" but with different application versions ("Remote" has v28.9 build 2 and the extraneous "Workstation" has v28.7 build 1)