Beijer Electronics (formerly QSI Corporation)

Flash File limitations in /drv1 directory?
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Author:  nwest [ Thu Jul 08, 2010 1:54 pm ]
Post subject:  Flash File limitations in /drv1 directory?

I have a G58 terminal and am using the flash file system to log data and allow transfers over USB to my PC.
My program writes a small (4Kb) file at the end of a test. I run a series of tests during the day and then plug into my PC to offload the data files. It all works perfectly unless I try to save more than 170 (sometimes 171) files. On the 170th file it fails to save with an error message of "Cannot open file". If I then delete the data files, it works again.

I read in the data sheet that there is a 128 char file name limit and a 256 char directory name limit. Is there a number of files per directory limit?

The path to my data is /drv1/XXXXX.txt so the path name should never be more the 128chars.

I save to the /drv1 directory so that the USB will recognize it. Is there a special limitation in that directory?

Any info would be appreciated.

Author:  Jeremy [ Thu Jul 08, 2010 2:29 pm ]
Post subject:  Re: Flash File limitations in /drv1 directory?

The /drv1 directory of the G58, is actually the root directory of a FAT file system. This is, of course, the same file system that appears to your PC as a lettered drive (e.g., E:\). FAT has a limit to the number of entries that can appear in the root directory.

The actual maximum number of files that can be saved may vary as long file names may require multiple entries to record the file name, as well as how the file system was formatted. I just connected a G58 to my PC and copied a bunch of small files, and got an error at about 190 files.

Your best bet is to create a subdirectory under /drv1 and then you should be able to put as many files as you like. I was able to copy several hundred files to a subdirectory

Author:  nwest [ Thu Jul 08, 2010 2:39 pm ]
Post subject:  Re: Flash File limitations in /drv1 directory?

Thank you for the quick response. I was not aware of the FAT root limitation.


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