XPlotter error, need administrator privilege (doesnt occur with wplotgenerator) #3
Comments
Blagodarenko
commented
Jan 4, 2017
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can you get more info about your drive and OS? |
Pascal66
commented
Jan 5, 2017
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os: w10 |
Blagodarenko
commented
Jan 6, 2017
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https://msdn.microsoft.com/en-us/library/windows/desktop/aa365544(v=vs.85).aspx also https://msdn.microsoft.com/en-us/library/windows/desktop/aa364404(v=vs.85).aspx |
Pascal66
commented
Jan 6, 2017
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I agree, but that was working with wplotgenerator wich doesnt need elevated privilege, so why xplotter need it ? |
Blagodarenko
commented
Jan 9, 2017
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wplotgenerator writing data to the file sequentially, and you get unoptimized (for reading) plot. "When you use SetEndOfFile to increase the length of a file, the logical file length changes and the necessary disk space is allocated, but no data is actually physically written to the disk sectors corresponding to the new part of the file. The valid data length remains the same as it was. This means you can use SetEndOfFile to make a file very large very quickly, and if you read from the new part of the file you'll just get zeros. The valid data length increases when you write actual data to the new part of the file. That's fine if you just want to reserve space, and will then be writing data to the file sequentially. But if you make the file very large and immediately write data near the end of it, zeros need to be written to the new part of the file, which will take a long time. If you don't actually need the file to contain zeros, you can use SetFileValidData to skip this step; the new part of the file will then contain random data from previously deleted files." |
Pascal66
commented
Jan 9, 2017
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Agree another time. but it doesnt explain the need of elevated privileges. |
Pascal66
closed this
Jan 9, 2017
Blagodarenko
commented
Jan 10, 2017
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My test for create 2Tb plot: SetFileValidData() - unsecure function, that's why it need elevated privileges (example of using http://www.drdobbs.com/beware-of-file-slack-attacks/184405835) |
Pascal66 commentedJan 4, 2017
XPlotter v1.0 for BURST
programmers: Blago, Cerr Janror, DCCT
Checking directory...
Drive x:\ info:
Name: Disque 1
File system: NTFS
Serial Number: 3916110242
FILE_SUPPORTS_SPARSE_FILES: no
Bytes per Sector: 512
Sectors per Cluster: 2
The token does not have the specified privilege.
For faster writing you should restart plotter with Administrative rights.
Error creating stream for file x:\burst\plots\12247834136664705924_2400000001_100096_100096
x:\Burst>