Syzygy 7 KNNPPvKR.rtbw at Lichess corrupted?

[mbabigian]

I've been downloading the 7 piece syzygy tables and have run into one that doesn't match the SHA hash I have for it.

KNNPPvKR.rtbw hashes to:

275d5c38fc52d25c0cd70a4ba095b13311d7bf878f2c3db41c9341d8475d8426

but the hash I have for it is:

cfb7a50cb82ec5741b8e2f8f37610a375ed3d03f396214af05567a61668a1783

I've downloaded it more than once. Is the file corrupt or the hash wrong? If corrupt, what is an alternate download source?

Thanks in advance,
Mike.

[Eduard]

http://tablebase.sesse.net/syzygy/

[Ajedrecista]

Hello:

I've been downloading the 7 piece syzygy tables and have run into one that doesn't match the SHA hash I have for it.

KNNPPvKR.rtbw hashes to:

275d5c38fc52d25c0cd70a4ba095b13311d7bf878f2c3db41c9341d8475d8426

but the hash I have for it is:

cfb7a50cb82ec5741b8e2f8f37610a375ed3d03f396214af05567a61668a1783

I've downloaded it more than once. Is the file corrupt or the hash wrong? If corrupt, what is an alternate download source?

Thanks in advance,
Mike.

The same issue was noted back in September, 2018:

Re: 7-men Syzygy attempt

You can continue reading that thread to check if it was solved. There is a FTP link in that thread by the way:

ftp://ftp.chessdb.cn/pub/syzygy/7men/

Good luck!

Regards from Spain.

Ajedrecista.

[mbabigian]

Eduard, thank you for the reply, but http://tablebase.sesse.net/syzygy/ returns:

"Forbidden"
"You don't have permission to access this resource" when I click the file.

[mbabigian]

Ajedrecista, thank you for the thread discussion. I downloaded the file from the China site (ftp://ftp.chessdb.cn/pub/syzygy/7men/), but the file there gives the same SHA hash as the file on Lichess.

I'm assuming both sites have the same corrupt file.

[Ajedrecista]

Hello again:

Edward, thank you for the reply, but http://tablebase.sesse.net/syzygy/ returns:

"Forbidden"
"You don't have permission to access this resource" when I click the file.

I can download the file from Sesse, just normal click on the file (not right click and open in new tab because the 'Forbidden' message appears).

I am sorry for the FTP. The file had a date from June, 2018 and the post describing the issue is from September, 2018. I admit that is strange that the file has not been replaced after the warning.

Regards from Spain.

Ajedrecista.

[xr_a_y]

This one http://tablebase.sesse.net/syzygy/7-WDL/KNNPPvKR.rtbw

Code: Select all

wget http://tablebase.sesse.net/syzygy/7-WDL/KNNPPvKR.rtbw
--2020-02-20 21:19:20--  http://tablebase.sesse.net/syzygy/7-WDL/KNNPPvKR.rtbw
Résolution de tablebase.sesse.net (tablebase.sesse.net)… 193.35.52.50, 2001:67c:29f4::50
Connexion à tablebase.sesse.net (tablebase.sesse.net)|193.35.52.50|:80… connecté.
requête HTTP transmise, en attente de la réponse… 200 OK
Taille : 14609178768 (14G) [application/octet-stream]
Enregistre : «KNNPPvKR.rtbw»

KNNPPvKR.rtbw                                               100%[=========================================================================================================================================>]  13,61G  57,8MB/s    ds 4m 6s   

2020-02-20 21:23:25 (56,7 MB/s) - «KNNPPvKR.rtbw» enregistré [14609178768/14609178768]

is hashed to 275d5c38fc52d25c0cd70a4ba095b13311d7bf878f2c3db41c9341d8475d8426 here

Code: Select all

vivien@serv2:~$ sha256sum KNNPPvKR.rtbw 
275d5c38fc52d25c0cd70a4ba095b13311d7bf878f2c3db41c9341d8475d8426  KNNPPvKR.rtbw

as expected
http://tablebase.sesse.net/syzygy/7-WDL/SHA256SUMS

[mbabigian]

Vivien, thank you for the reply. If that is the case, the file is fine, but the hash I have for it is incorrect.

I get the 275d5... hash also

Mike.

[Albert Silver]

There are a number of defective files at Sesse too, which are available at Lichess, so it is not a black and white situation.

[mbabigian]

There are a number of defective files at Sesse too, which are available at Lichess, so it is not a black and white situation.

This is very unfortunate. After reading the linked threads, it appears that although "well intentioned" several folks wanted to provide a hash list for others by downloading the files, hashing, and posting them as gospel - a cardinal sin. Instead, they should have kindly requested the keepers of the originals to provide such hashes and if the request was refused, only then try to create hashes of copied copies. As it stands now, it is a confusing quagmire.

I have used the confusing threads to correct several hashes I have in my file of hashes and will continue the download process. I've retrieved about 25% of the set and will hopefully get a clean group of files from Lichess eventually. Unless Ronald de Man or Bojun Guo post an official hash list, I will post my corrected hash files that "match the Lichess data set" and specify that these hashes do not validate that Lichess has a correct set of files, but only that you downloaded correctly what they have (I will post no hashes I created. Only the hash list I updated from other posts and that it matched what I downloaded from Lichess). I may or may not download the 6x1 files, and therefore may not validate those hashes against Lichess files.

My download speed swings between 10Mbits/s to 60+Mbits/s when I'm watching it, so it will take a few weeks before I can post anything.

I appreciate everyone's help and history lesson of events.
Mike