What is a Program?

A Program is a collection of instructions that the computer follows to try and do a specific job. As an average user of operating system we've got many standard programs and methods available.

What is Shell?

The shell is a program that executes the codes types by user at terminal. It is also known as command interpreter. It act like a mediator which interpret the commands that user gives after which conveys them to the kernal which in turn ultimately executes them. The shell program is responsible for displaying a prompt on the screen and interpreting commands. These commands might be typed at the keyboard or stored in the file.

What is Kernel?

The centre of UNIX operating system is the kernel. The kernel controls usage of the computer hardware and copes with the computer memory and allocates the computer resources one user then to another. It is kernel that interact with the specific HW in machine language.

What are Device Files?

They're special files associated with numerous devices. They are collectively kept beneath the 'dev' directory. They contain the device drivers and associated data associated with proper functioning of device.

What are Directory Files?

A Directory file stores information about a directory, its relationship with other directories, what files and subfiles are stored inside it and access permissions. The file is updated everytime and alteration is made to the directory, its surrounding web directories and files and subdirectories under it.

What are Ordinary Files?

These are the files that store data, such as text information and programs.

What is Interpreter?

Interpreter is a software that translate one origin instruction into object code and the computer immediately execute that instruction before moving on to translate the next instruction. Interpreted program tend to take longer time to complete execution than compiled software programs. Every time a program is usually to be executed, it is to always be translated. Interpreted are often used during the program development phase.

What is BIOS?

BIOS is Basic Input Output System. This is a collection of programs that is stored in the ROM in personal computers. They are usually driver programs for standard devices. DOS call these device driver programs to complete I/O operations.