could somebody clarify what the meaning pseudo file system
means and how is it different to a regular file system
from different point views (users/processes/apps) .
2 Answers
'Pseudo-' means false, pretend. So "pseudo-filesystem" means a filesystem that doesn't have actual files – rather, it has virtual entries that the filesystem itself makes up on the spot.
For example, /proc
on many OSes is a procfs which dynamically generates directories for every process. Similarly, /sys
on Linux generates files and directories to represent hardware layouts. There are FUSE-based pseudo-filesystems for a lot of things.
/dev
may be a real filesystem (just a subdirectory of /
), or a virtual pseudo-filesystem (e.g. devfs), or a middle point such as Linux devtmpfs (which is a full in-memory filesystem but still creates device nodes out of nowhere).
A pseudo file system maintains information about the currently running system.
This information doesn't persist across reboots. It exists while the system in running only in RAM; in Window this would be the HKLM
.
In linux /dev
this includes things like /dev/tty#
/dev/ttyS#
they indicate devices as they are connected and they be created dynamically.
/sys
shows a representation of the physical devices in the machine.
/proc
maintain a lot of info about the current control set.
Example: free
command is just importing info from /proc/meminfo
file.
proc
is not the only pseudo file system , there isdev
,sys
.. , now what is it ?