FILE SYSTEM IN LINUX

:Linux system Filesystem:

There are two types of File system in Linux.
1. Physical File System
2. Logical File System.

1. Physical file System.
Physical file system means physical files available on Hard disk. E.g. C drive in windows & any directory name like /example in Linux.

2. Logical file system:
Logical file system Hierarchy is as shown above :

“/”

· “/” is called as root directory.It is the top of the file system structure

· All other directories are mounted under it.

“/root”
· This is the default home directory of administrator (i.e. root)

“/home”
· It contains all users home directory.

“/boot”
· This directory contains the kernel the core of Operating System.

· This also contains the files related to booting the system such as the boot loader and the initial ramdisk.

“/sbin”
· It contains administrative commands used by superuser (i.e. root)

“/bin”
· This directory contains commands used by the superuser & the normal user.

“/usr”
· It contains the programs & applications which are available for users (similar to program files on windows.)

“/var”
· It contains variable information such as logs & print queues.

“/dev”
· This directory contains devices nodes through which the operating system can access hardware and software devices on the system.

“/etc”
· It contains all configuration files.

“/proc”
· This directory is a mount point for virtual information about currently running system process.

· This directory is empty until the proc file system is mounted.

“/tmp”
· This directory contains temporary files used by system.

“/opt”
*It contains third party applications.
e.g. Corel word perfect.
Sun star office.

“/media”
- /media/cdRom
- /media/floppy

· It contains default mount points of removable media such as cdrom, floppy disk, pen drive.

“/lib”

* It contains library files need by number of different applications as well as Linux kernel.

History of Linux

***Linux ***

I am writing here brief introduction about Linux.

Features of Linux:
Open Source
Multitasking
Multi user
Portable: Can match with any hardware
Scalability: Can be used for any purpose.
Reliability
Inbuilt Firewall (iptable)


Now we will move to History of Unix.

In 1960’s scientist in AT&T lab named Ken Thomson has created 1st operating system known as Multics. This was built in purely in Assembly language. Its full form is Multiplexing Information & Computing System.
Drawbacks of system were that it was Machine dependent i.e. for each separate p.c. you have treat as different machine & different commands different settings etc.
So this went fail.
After 9 years in 1969 Ken Thomson met founder of C language Denis’s Ritchie
& they combinely created a new O.S. named UNICS (UNIPLEXING INFORMATION & COMPUTING SYSTEM) which was built 80% in C & 20% in Assembly lang.
After few days it was named as UNIX (100% C language).

After creating a O.S Ken Thomson started to giving lectures in universities. Students learnt UNIX & started to develop it. Some of vendors to use UNIX as base are




Vendors --------O.S


AT & T, Bell Labs------- Sys 3 sys 5


Sun ------Sun OS- Solaris


IBM------ AIX


SG ------IRIX


SCO ------SCO UNIX


BSD ------Free BSD LINUX



As these companies were started to dominate the computer world rest all company venders came together & formed Open Source foundation.

In 1990’s an under graduate student named LINUS TORVALDS from University of Helsinky designed UNIX like kernel on 386 Intel machine & gave this to Open Source Community. Linux kernel was bundled with many softwares from various distributors & it gave rise to many flavors of LINUX.

: LINUX DISTRIBUTORS:


Linux distributors are


1. Red Hat
2. Suse Linux
3. Mandriva Linux
4. Ubuntu
5. debian
6. Turbo Linux
7. Slackware Linux
8. Puppy Linux

In these most popular is red hat Linux.
Versions of Red Hat Linux.

Free Version -------------Commercial Editions
Red Hat 1 to Red Hat 9 --------



Fedora Core 1 -------------- RHEL 1


Fedora Core 2------------- -RHEL 2


Fedora Core 3-------------- RHEL 3


Fedora Core 4 --------------RHEL 3


Fedora Core 5 --------------RHEL 4


Fedora Core 6 --------------RHEL 5 beta

Free versions are freely distributed all over the world. But they dont have any support from Red Hat. In RHEL they give full support to their clients.