Page 152 - DCAP106_OPERATING_SYSTEM_TOOLS

Unit 9: The File System

You can mount the users’ home directories at /home (which is preferable) but you could very Notes
well mount it at /srv/export/systems/remote/disk/users.
The mount command by itself, without any arguments, displays a list of mounted file systems:

Example:

$ mount
/dev/sda8 on / type ext3 (rw,noatime)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
udev on /dev type tmpfs (rw,nosuid,relatime,size=10240k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620)
/dev/sda7 on /home type ext3 (rw,noatime)
none on /dev/shm type tmpfs (rw)
/dev/sda1 on /mnt/data type ext3 (rw,noatime)
usbfs on /proc/bus/usb type usbfs (rw,noexec,nosuid,devmode=0664,devgid=85)
The example discussed above, even though bloated with various other file systems we know
nothing about yet, tells us that the file system can be seen as follows:
/ (on /dev/sda8)
+- ...
+- dev/ (special: “udev”)
| +- pts (special: “devpts”)
| `- shm (special: “none”)
+- proc/ (special: “proc”)
| `- bus/
| `- usb/ (special: “usbfs”)
+- sys/ (special: “sys”)
+- home/ (on /dev/sda7)
`- mnt/
`- data/ (on /dev/sda1)
Overlooking the special mounts, it can be seen that the root of the file system is on device /
dev/sda8. From /home onwards, the file system is stored on /dev/sda7 and from /mnt/
dataonwards, the file system is stored on /dev/sda1.
Mounting allows programs to be uncertain about where your data is structured. From an
application (or user) point of view, the file system is one tree. Under the hood, the file system
structure can be on a single partition, but also on a dozen partitions, network storage, removable
media and more.

File Systems
Every medium which can enclose files is internally structured. The appearance of this structure
is part of the file system it uses. Windows users might remember that originally, Microsoft
Windows used FAT16 and later on FAT32 before they all migrated to one of the many NTFS
revisions currently in use by Microsoft Windows. Well, all these are in fact file systems, and
Linux has its own set as well.

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