Invalid WU / Failed Core download

[John Dean]

I got help here about a month ago with delays in getting WUs. I still get delays from time to time but not usually as bad as they were. However, the problem has suddenly got worse. I waited 20 hours after ending the previous WU:

[09:18:24] - Preparing to get new work unit...
[09:18:24] + Attempting to get work packet
[09:18:24] - Connecting to assignment server
[09:18:25] - Successful: assigned to (0.0.0.0).
[09:18:25] + News From Folding@Home: Welcome to Folding@Home
[09:18:25] Work Unit has an invalid address.
[09:18:25] - Error: Attempt #1 to get work failed, and no other work to do.
Waiting before retry.
[09:18:30] + Attempting to get work packet
[09:18:30] - Connecting to assignment server
[09:18:31] - Successful: assigned to (0.0.0.0).

...
through to
[04:23:57] + Attempting to get work packet
[04:23:57] - Connecting to assignment server
[04:23:57] - Successful: assigned to (0.0.0.0).
[04:23:57] + News From Folding@Home: Welcome to Folding@Home
[04:23:57] Work Unit has an invalid address.
[04:23:57] - Error: Attempt #33 to get work failed, and no other work to do.
Waiting before retry.
...
Finally
[05:12:03] + Attempting to get work packet
[05:12:03] - Connecting to assignment server
[05:12:04] - Successful: assigned to (171.64.122.88).
[05:12:04] + News From Folding@Home: Welcome to Folding@Home
[05:12:04] Loaded queue successfully.
[05:12:09] + Closed connections
[05:12:09]
[05:12:09] + Processing work unit

However, a new problem arose immediately:

[05:12:09] Core required: FahCore_7b.exe
[05:12:09] Core not found.
[05:12:09] - Core is not present or corrupted.
[05:12:09] - Attempting to download new core...
[05:12:09] + Downloading new core: FahCore_7b.exe
[05:12:10] + 10240 bytes downloaded
[05:12:10] + 20480 bytes downloaded
[05:12:11] + 30720 bytes downloaded
[05:12:11] + 40960 bytes downloaded
[05:12:11] + 51200 bytes downloaded
[05:12:11] + 61440 bytes downloaded
[05:12:11] + 71680 bytes downloaded
[05:12:11] + 81920 bytes downloaded
[05:12:11] + 92160 bytes downloaded
[05:12:11] + 102400 bytes downloaded
[05:12:11] + 112640 bytes downloaded
[05:12:11] + 122880 bytes downloaded
[05:12:12] + 133120 bytes downloaded
[05:12:12] + 143360 bytes downloaded
[05:12:12] + 153600 bytes downloaded
[05:12:12] + 163840 bytes downloaded
[05:12:12] + 174080 bytes downloaded
[05:12:12] + 184320 bytes downloaded
[05:12:12] + 194560 bytes downloaded
[05:12:12] + 204800 bytes downloaded
[05:12:12] + 215040 bytes downloaded
[05:12:12] + 225280 bytes downloaded
[05:12:12] + 235520 bytes downloaded
[05:12:12] + 245760 bytes downloaded
[05:12:13] + 256000 bytes downloaded
[05:12:13] + 266240 bytes downloaded
[05:12:13] + 276480 bytes downloaded
[05:12:13] + 286720 bytes downloaded
[05:12:13] + 296960 bytes downloaded
[05:12:13] + 307200 bytes downloaded
[05:12:13] + 317440 bytes downloaded
[05:12:13] + 327680 bytes downloaded
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[05:12:13] + 348160 bytes downloaded
[05:12:13] + 358400 bytes downloaded
[05:12:13] + 368640 bytes downloaded
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[05:12:14] + 389120 bytes downloaded
[05:12:14] + 399360 bytes downloaded
[05:12:14] + 409600 bytes downloaded
[05:12:14] + 419840 bytes downloaded
[05:12:14] + 430080 bytes downloaded
[05:12:14] + 440320 bytes downloaded
[05:12:14] + 450560 bytes downloaded
[05:12:14] + 460800 bytes downloaded
[05:12:14] + 471040 bytes downloaded
[05:12:14] + 481280 bytes downloaded
[05:12:15] + 491520 bytes downloaded
[05:12:15] + 501760 bytes downloaded
[05:12:15] + 512000 bytes downloaded
[05:12:15] + 522240 bytes downloaded
[05:12:15] + 532480 bytes downloaded
[05:12:15] + 542720 bytes downloaded
[05:12:15] + 552960 bytes downloaded
[05:12:15] + 563200 bytes downloaded
[05:12:15] + 573440 bytes downloaded
[05:12:15] + 583680 bytes downloaded
[05:12:15] + 593920 bytes downloaded
[05:12:15] + 604160 bytes downloaded
[05:12:16] + 614400 bytes downloaded
[05:12:16] + 624640 bytes downloaded
[05:12:16] + 634880 bytes downloaded
[05:12:16] + 645120 bytes downloaded
[05:12:16] + 655360 bytes downloaded
[05:12:16] + 665600 bytes downloaded
[05:12:16] + 675840 bytes downloaded
[05:12:16] + 686080 bytes downloaded
[05:12:16] + 696320 bytes downloaded
[05:12:16] + 706560 bytes downloaded
[05:12:16] + 716800 bytes downloaded
[05:12:16] + 724218 bytes downloaded
[05:12:16] Verifying core Core_7b.fah...
[05:12:16] Signature is VALID
[05:12:16]
[05:12:16] Trying to unzip core FahCore_7b.exe
[05:16:16] - Couldn't open file FahCore_7b.exe
[05:16:16] + Error: Could not extract core
[05:16:16] + Core download error (#2), waiting before retry...
[05:16:32] + Downloading new core: FahCore_7b.exe
[05:16:40] Trying to unzip core FahCore_7b.exe
[05:20:40] - Couldn't open file FahCore_7b.exe
[05:20:40] + Error: Could not extract core

There were then a further 14 attempts to get the core, each one downloading the full 724,218 bytes before failing to open the file and failing to extract the core. Finally, after a further 6 hours

[11:41:04] + Downloading new core: FahCore_7b.exe
[11:41:12] Verifying core Core_7b.fah...
[11:41:12] Signature is VALID
[11:41:12]
[11:41:12] Trying to unzip core FahCore_7b.exe
[11:41:20] Decompressed FahCore_7b.exe (2101248 bytes) successfully
[11:41:20] + Core successfully engaged
[11:41:25]
[11:41:25] + Processing work unit
[11:41:25] Core required: FahCore_7b.exe
[11:41:25] Core found.
[11:41:25] Working on Unit 08 [February 22 11:41:25]
[11:41:25] + Working ...

Now I can live with delays in downloading WUs (I'm losing nothing nothing, FAH is misisng a tiny contribution) but these repeated attempts to download a new core are worrying. On this occasion, it only consumed 10 Mb of my month's allowance, but I'm on a capped account and if FAH were to call these kind of files up over and over again without my noticing (and I don't check FAH that often) I could end up in trouble with my ISP.
So - is there a fix for this problem? Failing that, is there some way to warn me about repeated file downloads or to prevent FAH getting the same file repeatedly?

[bruce]

There have been times when the servers run out of work to be assigned. Those times are really very rare, but it did happen about 24 hours ago so that probably explains all the assignments to 0.0.0.0 and failures to download new WUs.

There are 5 to 7 different analysis methods (FahCore_xx) that may be used by projects that you might be assigned. In your case, you received an assignment that needed a different FahCore_xx so the client downloaded the necessary software. It might happen again, but it's all downloaded automatically and only if you need it. Once you've got the ones you need, you shouldn't see this happening very often. In fact, some are rarely used so there's a good chance you won't need them all. After that, it's possible that you will see a similar download again if there is a revision to the analysis code but that probably happens only once a year or so.

When the client, itself, is revised, you have to go through the installation procedure again, but as long as you've already got the necessary FahCore_* software, it's unlikely that you'll need to download them again. In any case, it's all automatic so it's nothing to worry about.

[anandhanju]

...
[05:16:16] + Core download error (#2), waiting before retry...
[05:16:32] + Downloading new core: FahCore_7b.exe
[05:16:40] Trying to unzip core FahCore_7b.exe
[05:20:40] - Couldn't open file FahCore_7b.exe
[05:20:40] + Error: Could not extract core
There were then a further 14 attempts to get the core, each one downloading the full 724,218 bytes before failing to open the file and failing to extract the core...

Did you change anything to make the core download successfully the 15th time? Is this the client on the XP Home SP2 machine with a Broadband connection? Some folders have had this problem when their internet connection isn't reliable (dropped packets etc. resulting in extraction errors of the fahcore). As bruce said, core downloads are quite infrequent, so you may not notice this for quite a while. In any case, http://fahwiki.net/index.php/Downloadin ... s_manually if automatic downloads do not work

[bruce]

There were then a further 14 attempts to get the core, each one downloading the full 724,218 bytes before failing to open the file and failing to extract the core...

Did you change anything to make the core download successfully the 15th time? Is this the client on the XP Home SP2 machine with a Broadband connection? Some folders have had this problem when their internet connection isn't reliable (dropped packets etc. resulting in extraction errors of the fahcore). As bruce said, core downloads are quite infrequent, so you may not notice this for quite a while. In any case, http://fahwiki.net/index.php/Downloadin ... s_manually if automatic downloads do not work

Repeated download attempts have never been adequately explained. Most people do receive them on the first pass but we do ge occasional reports like this one. A bad internet connection is one of the suspected causes, as you say. This is compounded by the fact that the browser cache often makes the problem worse. Once you've got a bad download in your cache, attempting to download it again often just gives you the same copy again rather than actually downloading it again.

If anybody knows a fix for this please let us know.


Fixed quoting. 7im

[Cajun_Don]

If anybody knows a fix for this please let us know.

The solution to repeated corrupt download files, is to delete you browser's cache. Shut down F@h gracefully. Deletes you browser cache, then shut down your browser.
Then restart F@h and it should download the newest core that is needed.

If you still can't download without a corrupt download, shut down F@h gracefully. Repeat clearing your browser cache. Shutdown browser, and shutdown OS gracefully, and Shut down computer completely with no power (don't use restart to shutdown computer). Turn power back on to computer, and when OS has been fully loaded (may take several minutes), start F@h client and it should start downloading the correct core without corruption.

If that doesn't resolve your problem, post your log.txt file.

Good Luck.

[John Dean]

In your case, you received an assignment that needed a different FahCore_xx so the client downloaded the necessary software. It might happen again, but it's all downloaded automatically and only if you need it. Once you've got the ones you need, you shouldn't see this happening very often

But on each occasion the log says it was downloading "new core: FahCore_7b.exe" and on each occasion the file size was 724218 bytes exactly. That happened 15 times in succession. So it was downloading the identical file multipl times and it clearly didn't stop when I'd got the one I 'needed' - ie the one that eventually worked - until the 15th time.
What's to stop the program downloading the same file over and over until I exceed my ISPs allowed download limit?

[John Dean]

...
[05:16:16] + Core download error (#2), waiting before retry...
[05:16:32] + Downloading new core: FahCore_7b.exe
[05:16:40] Trying to unzip core FahCore_7b.exe
[05:20:40] - Couldn't open file FahCore_7b.exe
[05:20:40] + Error: Could not extract core
There were then a further 14 attempts to get the core, each one downloading the full 724,218 bytes before failing to open the file and failing to extract the core...

Did you change anything to make the core download successfully the 15th time? Is this the client on the XP Home SP2 machine with a Broadband connection? Some folders have had this problem when their internet connection isn't reliable (dropped packets etc. resulting in extraction errors of the fahcore). As bruce said, core downloads are quite infrequent, so you may not notice this for quite a while. In any case, http://fahwiki.net/index.php/Downloadin ... s_manually if automatic downloads do not work

Didn't change a thing. In fact, I didn't even know any of this was happening until it was all over and I happened to check progress. I was dumbfounded to see how much time had been spent getting the new WU and then downloading the same Core file over and over.
Yep - XP2 Home SP2 with a reliable Broadband connection.
As I say, I'm not bothered about downloading a new core file, just about downloading the same one 15 times (coulda been 100 for all I know if something hadn't fnally worked)

[bruce]

But on each occasion the log says it was downloading "new core: FahCore_7b.exe" and on each occasion the file size was 724218 bytes exactly. That happened 15 times in succession. So it was downloading the identical file multipl times and it clearly didn't stop when I'd got the one I 'needed' - ie the one that eventually worked - until the 15th time.
What's to stop the program downloading the same file over and over until I exceed my ISPs allowed download limit?

I don't know anything that can prevent this except getting an internet connection that doesn't create the error in the first place. Perhaps there's a way to force the file to be erased from the cache so it will ACTUALLY be downloaded again when the FAH client retries the download. Your OS is saving you the time involved in downloading it again by re-using the copy from the cache, so it's not clear that your ISP is seeing all the traffic that you think it's seeing.

[John Dean]

But on each occasion the log says it was downloading "new core: FahCore_7b.exe" and on each occasion the file size was 724218 bytes exactly. That happened 15 times in succession. So it was downloading the identical file multipl times and it clearly didn't stop when I'd got the one I 'needed' - ie the one that eventually worked - until the 15th time.
What's to stop the program downloading the same file over and over until I exceed my ISPs allowed download limit?

I don't know anything that can prevent this except getting an internet connection that doesn't create the error in the first place. Perhaps there's a way to force the file to be erased from the cache so it will ACTUALLY be downloaded again when the FAH client retries the download. Your OS is saving you the time involved in downloading it again by re-using the copy from the cache, so it's not clear that your ISP is seeing all the traffic that you think it's seeing.

If that's what's happening, why does the log file record that it's getting the file again and again by downloading? It's the FAH log that's telling me there are multiple downloads of the same file.
And I have to say I haven't had *any* problems with my ISP since switching to them last December and they are regarded as one of the most reliable in the UK.
I'll keep track of my data transfer totals when I quit the computer and check, if the Core problem rpeats when I'm away from the computer, how much data download is recorded by Netmeter compared to what it says in the FAH log.