The Superuser: Root Disks and Partitions Making New Partitions Mounting Filesystems Mounting a Filesystem: mount Mounting Other Filesystems Unmounting a Filesystem: umount Sample /etc/fstab Filesystem Types

1. EssEntial nEEds of
administration
PrEsEntEd to:- mr. Purushottam das
PrEsEntEd By:- PaPu Kumar
sEction:- B
roll no.:- 2061424(47)
sEmEstEr:- iii

2. TOPICS
 The Superuser: Root
 Disks and Partitions
 Making New Partitions
 Mounting Filesystems
 Mounting a Filesystem: mount
 Mounting Other Filesystems
 Unmounting a Filesystem: umount
 Sample /etc/fstab
 Filesystem Types

3. The Superuser: Root
 Every Linux system has a user called ‘root’
 The root user is all-powerful
 Can access any files
 The root user account should only be used for system administration, such as installing
 software
 When logged in as root, the shell prompt usually ends in #
 Usually best to use su for working as root:
 $ whoami
 fred
 $ su -
 Password:
 # whoami
 root

4. Concepts: Disks and Partitions
 A hard disk provides a single large storage space
 Usually split into partitions
 Information about partitions is stored in the partition table
 Linux defaults to using partition tables compatible with Microsoft Windows
 For compatibility with Windows, at most four primary partitions can be made
 But they can be extended partitions, which can themselves be split into
smaller logical partitions
 Extended partitions have their own partition table to store information about
logical
 partitions

5. Making New Partitions
 Create new partitions with the n command
 Choose whether to make a primary, extended or logical partition
 Choose which number to assign it
 fdisk asks where to put the start and end of the partition
 The default values make the partition as big as possible
 The desired size can be specified in megabytes, e.g., +250M
 Changes to the partition table are only written when the w command is
given

6. Filesystems
 Some confusion surrounds the use of the term ‘filesystem’
 Commonly used to refer to two distinct concepts
 1. The hierarchy of directories and files which humans use
to organise data on a system
 (‘unified filesystem’)
 2. The formatting system which the kernel uses to store
blocks of data on physical media
 such as disks (‘filesystem types’)

7. Disk Naming
 The device files for IDE hard drives are /dev/hda to /dev/hdd
 hda and hdb are the drives on the first IDE channel, hdc and hdd the ones
on the second channel
 The first drive on each channel is the IDE ‘master’, and the second is the
IDE ‘slave’
 Primary partitions are numbered from 1–4
 Logical partitions are numbered from 5
 The devices /dev/hda, etc., refer to whole hard disks, not partitions
 Add the partition number to refer to a specific partition

8. Changing Partition Types
 Each partition has a type code, which is a number
 The fdisk command shows a list of known types
 The command t changes the type of an existing Partition
 Enter the type code at the prompt
 Linux partitions are usually of type ‘Linux native’ (type 83)
 Other operating systems might use other types of partition,
many of which can be understood by Linux

9. Mounting Other Filesystems
 mount /dev/sdb3 /mnt/extra mounts the filesystem stored in
the /dev/sdb3 device on the
 mount point /mnt/extra
 You may occasionally need to specify the filesystem type
explicitly:
 # mount -t vfat /dev/hdd1 /mnt/windows
 Allowable filesystem types are listed in the mount(8)
manpage
 To see a list of the filesystems currently mounted, run mount
without any options

10. Configuring mount: /etc/fstab
 The /etc/fstab file contains information about filesystems
that are known to the system administrator
 Specifying a filesystem in /etc/fstab makes it possible to use
its mount point as the only argument to mount
 /etc/fstab also configures which filesystems should be
mounted at boot-up
 Each line in /etc/fstab describes one filesystem
 Six columns on each line

11. Sample /etc/fstab
 A sample /etc/fstab file:
 # device mount-point type options (dump) pass-
no
 /dev/hda3 / ext2 defaults 1 1
 /dev/hda1 / boot ext2 defaults 1 2
 /dev/hda5 / usr ext2 defaults 1 2
 /dev/hdb1 / usr/local ext2 defaults 1 2
 /dev/hdb2 / home ext2 defaults 1 2
 none / proc proc defaults 0 0
 /dev/scd0 / mnt/cdrom iso9660 noauto, users, 0 0
 /dev/fd0 /mnt/floppy auto noauto, users 0 0

12. Filesystem Types
 The most common filesystem types are:
 ext2 The standard Linux filesystem
 iso9660 The filesystem used on CD-ROMs
 proc Not a real filesystem, so uses none as the device. Used as a way
 for the kernel to report system information to user processes vfat The
filesystem used by Windows 95
 auto Not a real filesystem type. Used as a way of asking the mount
 Networked filesystems include nfs (Unix-specific) and smbfs (Windows
or Samba)
 Other, less common types exist; see mount(8)

13. THANK U