Proc directory on CompactFlash

Jul 01, 2006 3 Replies

Murray R. Van Luyn schrieb:

Only the /proc directory itself should exist (empty) on your root drive. Then say "mount -t proc proc /proc" somewhere in your startup or put the equivalent line in /etc/fstab if you have that.

The *contents* of /proc are created directly by the kernel whenever it's accessed - reading a file in proc really connects your user space program directly to some kernel function that produces its content on-the-fly. Same for writing - your process gets connected to some kernel function that takes the data from your application and does something with it.

So except for the top /proc directory itself, nothing in /proc exists on any disk.

Linards Ticmanis

Hi,



I want to build a small RTLinux system on a CompactFlash, but don't know what to do with the /proc directory.



I think I'm supposed to put the /tmp directory on a TMPFS in ram to avoid wearing out the flash device too quickly.



I've heard of the contents of /proc being referred to as 'virtual'. Does that mean they are not actually stored on disk and can then be forgotten about? Otherwise, if the contents of /proc really are files stored on a disk, then do I do the same thing with the /proc directory as the /tmp directory?



Regards, Murray R. Van Luyn.


Thanks Linards. That explains everything nicely.

Regards, Murray R. Van Luyn.

May be all root (/) system put in RAM or only / and /usr leave on CF

This my example:

#mount -t ext2 /dev/hdc /mnt/cflash

#cd /mnt/cflash #ls

boot/ usr/ var/

#cd boot/ && ls

grub/ vmlinuz initrd.gz

boot/ - kernel, initrd image - root system include /proc, /sys, /tmp /bin, /sbin, /lib, /dev usr/ - all users application var/ - variable data

------------------------ Ex. 2

mount -t tmpfs none /tmp -o rw mkdir -p /tmp/proc mount -t proc none /tmp/proc -o rw ln -s /tmp/proc /proc

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