Reading large data files - Set File Position errors???

[rmp]

Hi folks,

I'm hoping that you can help me figure out how to read large binary data files (>4GB) using LV 8.

I have:
 - LV 8
 - WinXP and Mac OSX

I have looked at a few of my large files, and here is what I'm finding:
- I can use "Set File Position" function to set the file pointer >4GB, and I see no error
- if I read the contents of that file location I get bad data (C code reads the contents, and I get the expected value)
- if I place a "Get File Position" function immediately after the "Set File Position", then I see that the reported file position does not agree with the commanded position to "Set File Position". In one file it was off by 2 bytes; in another file it was off by 1 byte.

I've tried:
1) changing the data types of the parameters fed to "Set File Position" (U64, I64, DBL) - no change
2) smaller files - that works fine

Thanks, in advance,
RMP

[rmp]

The plot thickens:
 - it looks like the Mac has no problem with files > 4GB (I tried a 5 GB file)
 - On my Dell laptop/WinXP/NTFS: as soon as I try to Set File Position > FFFFFFFF (32 bit address) the Get File Position reports a bad address (note: no error reported)
 - I get the same behavior on another Desktop PC (I don't have machine details because I'm "remote desktop"ing to it); it's also WinXP/NTFS

I searched this forum for related threads, but didn't find anything. I find it hard to believe that this is a bug... I suspect that I'm doing something wrong...

I've attached my simple test program. You'll need to supply your own large data file.

[NIJanell]

Hello RMP,

This is a reported issue - the VI you are referring to cannot handle files larger than 4 GBs.  However, the maintance release 8.0.1 will fix this issue.  You can read more about the issue here and you can find the patch here.

Happy programming!

Janell R | Applications Engineer

[rmp]

Thanks Janell,
Yes, 8.0.1 has fixed the large file access problem...

As always, I greatly appreciate NI's speedy reply to questions in this forum.
RMP