Checking for USB drive from code

[sveremey]

Hello,

I have an application where we are logging data to a text file on a USB drive at /media/disk-0/

 

This is working, the file is generated correctly. However, I need to know if the USB drive is connected or not. If I try to write the file when there is no drive I get some watchdog issues in the background.

 

So, can anyone tell me how to detect this drive? I don't care if it is through PMAC script or C code, either will do. I don't need millisecond frequency checking either, I can schedule it every second or so.

 

I have tried stat() and it seems to always say the directory is present even when the drive is removed. so this doesn't work:

 

struct stat st;

if(stat("/media/disk-0/",&st) == 0)

{

bUSB_Ready = 1;

}

else

{

bUSB_Ready = 0;

}

 

I've also tried adding a directory in the root of the USB drive, I can tell the customer they need that for it to work (so it would be /media/disk-0/LOGS or whatever). When I try to detect that I never see the drive, even when it is plugged in.

 

Ideas welcome!

 

Thanks, Steve

[Omron Forums Support]

Steve,

 

Try this, it's working on my CK3E.

 

char bUSB_Ready = 0;
FILE *f = popen("mount | grep /media/disk-0", "r");
if (NULL != f)
{
      /* test if something has been outputed by 
      the command */
      if (EOF == fgetc(f)) {}
      else
      {
            bUSB_Ready = 1;
      }        
      /* close the command file */
      pclose(f);        
}

[illop]

Hi Eric

 

Where can I get some documents or examples related to the logging on USB in C-app?

[Omron Forums Support]

We have an example in this App note.

http://forums.deltatau.com/filedepot/download.php?f=Power%20PMAC/Application%20Notes/Saving%20Files%20on%20Power%20PMAC%20or%20External%20Media.pdf [FILE REMOVED]

 

Look at the "Saving Files on External Flash Devices" section starting on page 3.

 

At one point the app note instructs you to connect over telnet by typing a command windows command. I would suggest connecting with SSH through putty instead. Telnet may be disabled on newer form factors with the expectation that SSH will be used instead.