As you all know linux treating everything as a File so today we will
discuss about devices management in linux based operating system.
Modern linux is managed by devices and all the distributions are capable of detecting devices running time of os.
Hotplugging is achieved in linux distro by using three most popular components .
1. udev
2. Hal
3. dbus
Important:
Udev:- create and delete dynamic directory nodes in all linux distribution
under /dev directory when ever you plug or unplug any device.
Dbus: this is like system bus which is used for interprocess communication
Hal : Hal gets information from udev service , when devices is connected
it creates XML representation of the devices. It then notifies the current desktop notification application like (nautilus) with the help of Dbus and nautilus will the open the mount devices for user.
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More about Udev:
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Udev is the device manager for linux kernel which create and remove devices nodes in /dev directory dynamically . it is the successor of devfs and hotplug . It run in user space and user can change devices name using udev rules.
Note: Udev depends on the proc and sys file systems and they must be mounted on /proc and /sys
you can check from /etc/fstab file they must be mounted persistently.
you can find udev rules at /etc/udev/rules.d
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More about /dev
===============
1. /dev/autofs :- Normally used in autofs server where this file is used to mount remote directories locally. This is done automatically when user tries to login by mounting remote directory. The mounting is done by using this hardware file. With out this hardware file we can not do automount in a Linux distro.
2. /dev/console, /dev/tty, /dev/tty1 to /dev/tty63, /dev/ttyS, /dev/ttyS0 to /dev/ttyS31 files and /dev/pts
these device file are called terminal or console which is generally used in run level 1 , also used for pseudo terminal
3. /dev/loop this directory is used for managing CD/DVM in linux KVM and VMWare os image files.
4. /dev/randam and /dev/urandom
used for generating random chars for kernel purpose.
5. /dev/null and /dev/zero
used for generating empty file and observing unwanted outputs.
Note: /dev/zero is used to create files with no data but it require size (a file filled with Zeros)
dd if=/dev/zero of=/root/abc.txt bs=4096 count=1000
OR
[root@4hathacker rules.d]# strace cat /dev/zero
6. /dev/ppp
This file is used to connect your mobile or GPRS/3G enabled devices to connect and communicate with linux based system.
Modern linux is managed by devices and all the distributions are capable of detecting devices running time of os.
Hotplugging is achieved in linux distro by using three most popular components .
1. udev
2. Hal
3. dbus
Important:
Udev:- create and delete dynamic directory nodes in all linux distribution
under /dev directory when ever you plug or unplug any device.
Dbus: this is like system bus which is used for interprocess communication
Hal : Hal gets information from udev service , when devices is connected
it creates XML representation of the devices. It then notifies the current desktop notification application like (nautilus) with the help of Dbus and nautilus will the open the mount devices for user.
==============
More about Udev:
==============
Udev is the device manager for linux kernel which create and remove devices nodes in /dev directory dynamically . it is the successor of devfs and hotplug . It run in user space and user can change devices name using udev rules.
Note: Udev depends on the proc and sys file systems and they must be mounted on /proc and /sys
you can check from /etc/fstab file they must be mounted persistently.
you can find udev rules at /etc/udev/rules.d
===============
More about /dev
===============
1. /dev/autofs :- Normally used in autofs server where this file is used to mount remote directories locally. This is done automatically when user tries to login by mounting remote directory. The mounting is done by using this hardware file. With out this hardware file we can not do automount in a Linux distro.
2. /dev/console, /dev/tty, /dev/tty1 to /dev/tty63, /dev/ttyS, /dev/ttyS0 to /dev/ttyS31 files and /dev/pts
these device file are called terminal or console which is generally used in run level 1 , also used for pseudo terminal
3. /dev/loop this directory is used for managing CD/DVM in linux KVM and VMWare os image files.
4. /dev/randam and /dev/urandom
used for generating random chars for kernel purpose.
5. /dev/null and /dev/zero
used for generating empty file and observing unwanted outputs.
Note: /dev/zero is used to create files with no data but it require size (a file filled with Zeros)
dd if=/dev/zero of=/root/abc.txt bs=4096 count=1000
OR
[root@4hathacker rules.d]# strace cat /dev/zero
6. /dev/ppp
This file is used to connect your mobile or GPRS/3G enabled devices to connect and communicate with linux based system.
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