Main Components of Linux OS

File Management in linux

A file is a collected of related information defined by its creator. Computer can store files on the disk (secondary storage), which provide long term storage. Some examples of storage media are magnetic tape, magnetic disk and optical disk. Each of these media has its own properties like speed, capacity, data transfer rate and access methods.

A file systems normally organized into directories to ease their use. These directories may contain files and other directions.

Main-Memory Management

Primary-Memory or Main-Memory is a large array of words or bytes. Each word or byte has its own address. Main-memory provides storage that can be access directly by the CPU. That is to say for a program to be executed, it must in the main memory.
The major activities of an operating in regard to memory-management are:
Keep track of which part of memory are currently being used and by whom.
Decide which process are loaded into memory when memory space becomes available.
Allocate and deallocate memory space as needed.

Linux Process Management

The operating system manages many kinds of activities ranging from user programs to system programs like printer spooler,file server etc. Each of these activities is encapsulated in a process. A process includes the complete execution context (code, data, PC, registers, OS resources in use etc.).
    It is important to note that a process is not a program. A process is only ONE instant of a program in execution. There are many processes can be running the same program. The five major activities of an operating system in regard to process management are..

• Creation and deletion of user and system processes.
• Suspension and resumption of processes.
• A mechanism for process synchronization.
• A mechanism for process communication.
• A mechanism for deadlock handling.

What is shell program?

• A shell is a program that provides the traditional, text-only user interface for Unix-like operating systems. Its primary function is to read commands that are typed into a console (i.e., an all-text display mode) or terminal window (an all-text window) in a GUI (graphical user interface) and then execute (i.e., run) them. The term shell derives its name from the fact that it is an outer layer of an operating system. A shell is an interface between the user and the internal parts of the operating system (at the very core of which is the kernel).

• You can control and activate all the process in Linux from the shell .login for shell access. There are 7 terminals for Linux. 6 terminals are non - GUI and 1 terminal for GUI access. 

• You can login to each terminal using Alt + Ctrl + F1 , F2, .. F7. Each terminals will request your username and password for login. If you want to use the shell in the graphical interface (GUI), press Alt + F2 and type "konsole". User will have permission to access only your /home/user directory and other directories in it.