LabView limitation : working with File > 2 Go

[educhene]

Hi,

I'm acquiriring data in real time from several cards et high frequencies (102400 Hz).

The acquisition can last 10 hours and so the file can have size like 150 Go.

All labview file functions work with int32 to set offset, size of file... in byte.

How Can I do ?? (example : I have a 6 Go file : how can I know it's size with labview ???)

[Mads]

There is a file library that you can use to work with larger files, check out the following page:

http://zone.ni.com/devzone/learningcenter.nsf/webmain/E4E8EAB77D50AD6A86256E6800571306

[educhene]

Thanks for your answer Mads.

It's very interresting.

But I have a problem with the H5Screate_simple.vi and H5E_GetError.vi Vis : a zlib.dll is missing.

[tst]

Go to openg. It is a collection of LV toolkits. One of those should be a compression toolkit, which will also have zlib.dll installed.

[educhene]

I'm using a loop with Read Vi to seek in the file. It works well, But When my file is greater than 2 GB, I got a memory error (mémoire insuffisante pour terminer l'opération) when I try to read for example 263000 singles data.

This error appears when I want to read my 263000 values (not when seeking).
I don't understand why, because it runs well with a file less than 2 Gb even if I want to read more values.

Please find attached the example vi. Choose a file and run it : if your file size is less than 2 Gb (but have enough datas (ex : file size 10 Mb), it's ok, but if you run it with a file size more than 2 Gb you have the memory error.

Help please ...

[Isabelle]

Hello,

2 Gb is a restriction of your operating systems (see KB). You have to split your file.

Moreover what is your file system of your operating system ?

Anyway, I advice you to split your file.

Regards,

[rolfk]

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@educhene wrote:
I'm using a loop with Read Vi to seek in the file. It works well, But When my file is greater than 2 GB, I got a memory error (mémoire insuffisante pour terminer l'opération) when I try to read for example 263000 singles data.

This error appears when I want to read my 263000 values (not when seeking).
I don't understand why, because it runs well with a file less than 2 Gb even if I want to read more values.

Please find attached the example vi. Choose a file and run it : if your file size is less than 2 Gb (but have enough datas (ex : file size 10 Mb), it's ok, but if you run it with a file size more than 2 Gb you have the memory error.

Help please ...

---

As has been mentioned if you go to http://www.openg.org you will find in the File function Toolkit a library Large File Access, which works only on Windows as it calls directly into the WinAPI. Unlike other responses who said that the 2GB limit is a limit of the OS, Windows is actually able to work with larger file offsets. But LabVIEW currently does not make use of this option. The OpenG Large File functions mimic the LabVIEW low level FileIO functions but use a double precision floating point for all offset related parameters due to the lack of int64 support in LabVIEW.

Rolf Kalbermatter

[educhene]

No, I don't want to split my file into several with size < 2 GB : My acquisition file can have 150 GB size.

I don't have enough disk space and time to split it.
I'm under Windows XP and NTFS.

I can write file more than 2 GB and seek in them (by using the vi posted) with labview, but I don't understand with the read method at the end of the vi send me a memory error even if I read just a little datas.

Any answer ???

[educhene]

Thanks for your answer Rolfk : I'm using the Openg Commander to load package, and this package is not mentionned in it (or in the new site of OpenG).
I will try to use this library.

Thanks.

[rolfk]

It's part of the standard File package. When you install that package you get two new palettes actually. ONe with the different Open G extensions for File IO operations and another one for Large File IO.

Rolf Kalbermatter