LinuxQuestions.org
Review your favorite Linux distribution.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices


Reply
  Search this Thread
Old 01-09-2014, 08:59 AM   #1
adrhc
Member
 
Registered: Dec 2006
Location: Bucharest
Distribution: Ubuntu 16.04.1 LTS
Posts: 56

Rep: Reputation: 12
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 ?
 
Old 01-09-2014, 09:21 AM   #2
gengisdave
Member
 
Registered: Dec 2013
Location: Turin, Italy
Distribution: slackware
Posts: 323

Rep: Reputation: 72
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

Last edited by gengisdave; 01-09-2014 at 09:32 AM.
 
1 members found this post helpful.
Old 01-09-2014, 10:48 AM   #3
jpollard
Senior Member
 
Registered: Dec 2012
Location: Washington DC area
Distribution: Fedora, CentOS, Slackware
Posts: 4,654

Rep: Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255
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.
 
1 members found this post helpful.
Old 01-09-2014, 11:35 AM   #4
rknichols
Senior Member
 
Registered: Aug 2009
Distribution: CentOS
Posts: 3,124

Rep: Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346Reputation: 1346
Quote:
Originally Posted by jpollard View Post
Putting anything else in there could just cause confusion.
It is frequently recommended to put something meaningful to humans in that field, lest you one day get some message referring to "none".
 
Old 01-09-2014, 12:45 PM   #5
adrhc
Member
 
Registered: Dec 2006
Location: Bucharest
Distribution: Ubuntu 16.04.1 LTS
Posts: 56

Original Poster
Rep: Reputation: 12
This means that when no real device name is declared than the "device" would be considered the RAM ?
 
Old 01-09-2014, 01:55 PM   #6
jpollard
Senior Member
 
Registered: Dec 2012
Location: Washington DC area
Distribution: Fedora, CentOS, Slackware
Posts: 4,654

Rep: Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255Reputation: 1255
Quote:
Originally Posted by adrhc View Post
This means that when no real device name is declared than the "device" would be considered the RAM ?
Not exactly... it is both yes and no. The filesystem used MAY be ram based... Now system tables are represented as a filesystem (like the /proc, /sys filesystems), and that is in memory, but is not anything like a device or even ramdisk. But like some FUSE filesystems, it just means there is no dedicated device. FUSE interprets file access (via the fstab) into whatever the user definition is. If there is a device assocated with it, it would be specified as configuration to the FUSE implementation, and that can be a database system (MySQLfs is one) or some other representation.
 
Old 01-10-2014, 05:59 AM   #7
adrhc
Member
 
Registered: Dec 2006
Location: Bucharest
Distribution: Ubuntu 16.04.1 LTS
Posts: 56

Original Poster
Rep: Reputation: 12
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.

Last edited by adrhc; 01-10-2014 at 06:02 AM.
 
  


Reply

Tags
fstab


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
SSHFS fstab entries DeadlyMuffin Linux - Software 3 01-07-2010 10:30 AM
remount some of fstab entries j-me Linux - General 1 06-04-2009 02:21 PM
Immortal fstab entries tmoorman Mandriva 1 02-05-2005 03:52 AM
Remount using fstab entries keimdf Linux - Newbie 5 12-22-2004 07:48 AM
Entries in /etc/fstab kamransoomro84 Linux - General 6 05-05-2004 10:32 AM


All times are GMT -5. The time now is 12:05 AM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration