How Check Sd Inserted Or Not

[JyCet]

Hi all,
Does someone know under linux how to check if a sd is inserted or not ?
Thanks

 

[reiboul]

since you're french (cocorico )

man mount :
mount [-t type]
fournit la liste des systèmes de fichiers actuellement
montés (éventuellement ceux du type indiqué uniquement)

I don't know if that is what you are looking for h34r:

 

[JyCet]

ok donc pour "demonter" le sd:
umount /mnt/sd
et pour la "remonter"
mount /dev/mmcsd/disc0/part1 /mnt/sd

J'ai bon ?

Edit: j'ai testé, "device busy"

I ask that because I would like to change the SD with gp2x ON and with a program launched from this SD

 

[dmr]

In a shell script you can do:

if mount | grep -q disc0; then
	# SD is mounted
else
	# Not mounted
fi

 

[dmr]

Edit: j'ai testé at "device busy"

That means some process is using the SD, e.g. you are in a directory under /mnt/sd in the shell. If so just "cd /" before you unmount it.

Your program will have to close any files on the SD too and chdir() off the SD.

 

[JyCet]

Hi,

I found and will test that:

// all files already closed
//change dir to the root
chdir("/");
// umount the sd
umount ("/mnt/sd");
// CHANGE SD HERE
// mount the new sd
mount ("/dev/mmcsd/disc0/part1","/mnt/sd",...),
// return to the sd
chdir("/mnt/sd/");
// now DO MY STUFF
...

 

[JyCet]

Test complete but always impossible

If I launch any program from SD, it's impossible to umount /mnt/sd
If I add chdir("/"); in a program without any sd call inside this program, it's always impossible to umount /mnt/sd
Now if I copy a program in the NAND, this program do some call to the SD (like opendir() ) and close these call (closedir() ), I can umount /mnt/sd

 

[Daid]

Test complete but always impossible

If I launch any program from SD, it's impossible to umount /mnt/sd
If I add chdir("/"); in a program without any sd call inside this program, it's always impossible to umount /mnt/sd
Now if I copy a program in the NAND, this program do some call to the SD (like opendir() ) and close these call (closedir() ), I can umount /mnt/sd

Copy your 'SD switcher' to /tmp (which is tmpfs), run it from there, then you can unmount /mnt/sd. Without hurting the NAND

 

[JyCet]

Copy your 'SD switcher' to /tmp (which is tmpfs), run it from there, then you can unmount /mnt/sd. Without hurting the NAND

Sorry I dont understand what you mean by SD switcher and tmpfs.
I'm very beginer with linux and I would to create a RAMdisk (I can use around 15MB of free ram to create this RAMdisk) to copy some file from one SD to another.
That's why I search how to umount the sd and mount a new one

 

[Daid]

http://en.wikipedia.org/wiki/TMPFS <- tmpfs, in other words a filesystem in RAM memory.

With 'sd switched' I mean your program

 

[nuclear]

Hi all,
Does someone know under linux how to check if a sd is inserted or not ?
Thanks

3 ways from the top of my head:
1) stat the /mnt/sd and /mnt if both have the same device id, the sdcard is not mounted
2) open /proc/mounts and if you find any mention of sd there, it's mounted
3) open a pipe to the mount command and parse the output, if you see any mention of sd there, it's mounted

 

[JyCet]

Ok, i've looked inside fstab and understand now this line :

none /tmp /tmpfs Size=5M 0 0

It mean that we alway have 5MB allocated for a virtual /tmp folder in RAM.
Very good to know that, I'll investigate and do some test we this virtual folder

Thanks a lot