fstab entries with none
Hi, I have /etc/fstab:
/dev/ram0 / ext2 defaults 0 0 none /proc proc defaults 0 0 none /sys sysfs defaults 0 0 none /dev/pts devpts defaults 0 0 What means none ? I expected to be the device name, why is none ? |
they're all directories containing a virtual(pseudo)-filesystem, they don't use disk space and use a little bit of ram, so, they don't need to have a device associated, another way is 'proc /proc proc defaults 0 0' but it's the same
|
The "none" is just a place holder required for the syntax of the fstab file.
For filesystems that don't use a device, you can actually put anything in there you want. "none" satisfies the syntax, and if at some time in the future change the fstab file such that a real device is needed, it will immediately report the error, and identify that "device doesn't exist". Putting anything else in there could just cause confusion. |
Quote:
|
This means that when no real device name is declared than the "device" would be considered the RAM ?
|
Quote:
|
I read about /proc from http://www.tldp.org/LDP/Linux-Filesy...tml/index.html and now for /proc things make sense: it's just the configurable path for the OS where "proc" information should be put.
Modern Linux distributions include a /sys directory as a virtual filesystem (sysfs, comparable to /proc, which is a procfs), which stores and allows modification of the devices connected to the system, whereas many traditional UNIX and Unix-like operating systems use /sys as a symbolic link to the kernel source tree. -> now I understand /sys /dev/pts -> http://man7.org/linux/man-pages/man4/ptmx.4.html The summary is that (for a begginer only): the paths /proc, /sys, /dev/pts are not mount points for something existing on a HDD but locations where the OS is putting runtime information. That's why they have none - because is the OS's job to know who is the "device" where to store these runtime information. |
All times are GMT -5. The time now is 10:14 PM. |