User:B.A.Upamalika-2019T00473/sandbox

=  LINUX FILE SYSTEM - 2019T00473  =

About Linux file system
The file system is a very important part of any operating system. It is a built-in layer of Linux operating system. The file system is used to administer the process of storing and retrieving data in storage media. The file system affects directly the stability and security of the operating system. In the past, when the Linux-based Unix operating system was created, it was difficult to get a stable power supply. Also, it was very hard to work. The Unix OS was designed to be shared between several users simultaneously. The Linux file system has been designed with this in mind so that the Linux file system can be used more securely. Everything in Linux is represented as files, including physical devices.

The difference in file system types
The windows operating system is the most familiar with us. There is much difference both these file systems. Windows OS uses FAT16 / FAT32 or NTFS file formats to store data on the hard disk. Linux is a Unix based operating system. It is compatible with all Unix files. Today the most widely used file system model in the Linux os model is ext4. This is a very efficient and secure file system. Unix’s older file systems of ext,ext2 and ext3 can use on Linux. All the file systems of the windows are supported to Linux very easily. It is a unique capability in Linux. Therefore, after installing Linux on a Windows computer, the general files (without system files and exe files. There are audio / video, image, and text like this) in the Windows partitions can be used through Linux without any hassle. However, Windows file systems function as guest file systems in Linux. Therefore, it is necessary to introduce the Windows file system Linux OS in a special way. This process is called file system mount in Linux. In the past, this had to be done by the user himself, but nowadays in a Linux OS with a graphical interface (GUI), the upgrade process is done automatically when clicking on Windows partitions.

In windows, operating system computer hardware is considered to be a device that differs from the usual files. For example, a computer's hard disk and CD / DVD ROM can be viewed as files in Linux. It makes file management easier and allows you to customize different types of hardware.

There are many features inherited from the Linux operating system by Unix. For example, File1.txt, FILE1.txt and FILE1.TXT are all considered file names in Windows and cannot be kept in the same file folder. But Linux recognizes the above three files differently and can keep them in one place.

Advantages

 * Linux is more secure than other operating systems such as windows.


 * Linux is an open-source operating system. It is one of the main advantages of Linux. Its source code is open for everyone. Anyone can contribute and modify it.


 * When anyone uses Linux then they encounter a larger number of software updates. These updates are very fast in comparison to updates of other operating systems. We can be done easily from updates in Linux without facing any major issue or concern.


 * Linux operating system allows a large number of users to work simultaneously. It handles them efficiently. It presents a high performance in various and work stations.


 * All of Linux file directories (directories/folders in Windows) are created according to file usage. This makes file management easier and restricts access to important files in the file system unnecessarily for different users. This directly affects the security of the operating system. As a networked operating system, Linux has a systematic file hierarchy that allows users to easily manage user privacy. This imposes restrictions on individual users accessing the file of other users and can prevent file access altogether if necessary.

Types of Linux file system
When anyone tries to install Linux then they can see Linux offers many file system types like given in the below.

Ext

Ext2

Ext3

Ext4

ReiserFS

JFS

XFS

Btrfs

Swap

Major file system types
Now we discuss these each file given in the above.

Ext
Ext is for “extended file system” and this type was the first system created for Linux. Ext is an old one and no longer use due to limitation. Ext is a far from perfect so a lot of Linux distribution no longer support Ext.

Ext2
Ext2 file system was introduced in 1993. It was developed by Remy Card. Ext2 was the first default file system in several Linux distro. The maximum file size was 16GB-2TB.

 Ext3 

This file system was introduced in 2001. It is integrated into Kernel 2.4.15 with journaling feature, which is to improve reliability and eliminates the need to check the file system after an unclean shutdown. The maximum file size is 16GB- 2TB. This file system doesn’t support file recovery or disk snapshots.

Ext4
Ext4 was introduced in 2008. This is ass stable code were merged in the Kernel 2.6.28. Ext4 is backward compatibility. The maximum file size is 16GB to 16TB. This file system has an option to Turn Off journaling feature. It has new features like Sub Directory Scalability, Multiblock Allocation, Delayed Allocation, Fast FSCK etc.

ReiserFS
ReiserFS was introduced as an alternative to ext3. It has improved performance and advanced features.

JFS(Journaled File System)
This file system was developed by IBM for AIX UNIX. It is introduced as an alternative to the ext file system. JFS is an alternative to ext4 currently.

XFS
this file system was a high-speed JFS. It aimed parallel I/O processing. NASA still usage this file system.

Btrfs(B-Tree File System)
This file system focus on fault tolerance, fun administration, repair system etc. Btrfs isn’t recommended for a production system.

Features of Linux file systems

 * The Linux use forward-slash(/) to separate the components. For example, the windows use a backslash(\) to alternative this. C:\Users\Dsktop like this. But Linux uses forward-slash. /home/My document/Work like this.


 * Linux doesn’t use drive letters to organize the drive. In Linux we addressing a partition, a network, or an “ordinary” directory and a Drive.


 * Linux file system is case sensitive and it recognizes between lowercase and uppercase file names. For example, Linux recognizes test.txt and Text.txt files differently.


 * Linux recognizes between standard files and hidden files. Mostly, the configuration files are hidden in Linux os. The hidden files in Linux operating system are represented by a dot(.) before the file name(e.g. .none). If anyone needs to access these files, then they need to change the view in the file manager or need to use a specific command in the shell.

File system Hierarchy
File system hierarchy is very important for the efficiency and security of the Linux operating system. All of its file directories (directories/folders in Windows) are created according to file usage. This makes file management easier and restricts access to important files in the file system unnecessarily for different users. This directly affects the security of the operating system. As a networked operating system, Linux has a systematic file hierarchy that allows users to easily manage user privacy. This imposes restrictions on individual users accessing the file of other users and can prevent file access altogether if necessary.

/ (Root - root)
This is the root directory. is denoted as /. All other files are listed under root and no file exists outside the directory. Root Is accessed only by the administrator account and in Linux, it is called root (user).

/bin
This is called binary files in Linux. This directory contains such binary files that the files contained herein can be executed in single-user mode. All users have access to the files here.

/ sbin
It also contains binary files, but only the root user can execute them. The following is a list of programs used for various maintenance of the Linux operating system.

/ etc
This directory contains various configuration files related to programs. It also contains specialized files called scripts that run during the boot/startup and shutdown of the Linux operating system.

/ dev
All the hardware connected to the computer is shown here as a file. This is a unique feature of the Linux / Unix operating system.

/ proc
A program running on a computer is recognized by the operating system as a process. These can be divided into two main categories. That is, as user processes and system processes. Information about system processes can be found in this directory.

/ var
It contains files that automatically grow in size over time. This is where the log files on most Linux systems used as server computers are written.

/tmp
Temporary files created by the Linux operating system and user processes are stored in this directory. All files created here will be deleted during the reboot.

/ usr
This directory contains programs that every user of the operating system needs.

/ home
A file enclosure with the relevant username is created here to store the personal files of all normal users of the operating system. Usually, the operating system does not provide access to other users' files.

/ boot
This directory contains the operating system file. It also shows the Linux kernel and boot commands.

/ lib
Contains library files that support other programs and software.

/ opt
This directory contains third-party software that is not installed during the installation of the Linux operating system.

/ mnt
This directory is used by the system administrator to temporarily mount other file systems.

/ media
Removable devices can be temporarily mounted in this directory as needed by the user.

/ srv
This directory stores data related to services on server computer systems.   Reference

 https://www.tecmint.com/what-is-ext2-ext3-ext4-and-how-to-create-and-convert-linux-file-systems/

https://likegeeks.com/linux-file-system/

https://www.tutorialspoint.com/unix/unix-file-system.htm

https://www.linux.com/training-tutorials/linux-filesystem-explained/ 