Operating System

• An operating (sometimes abbreviated as "OS") system is a program that acts as an intermediate party between a user of a computer and the computer hardware.
• An operating system is the program that, after being initially loaded into the computer by a boot program, manages all the other programs in a computer.

The Objectives of OS are:

• Convenience: Make the computer more convenient to use making the user to focus on his main purpose (e.g. focus on document editing rather than spend time learning the commands).
• Efficiency: Allows computer system resources to be used in an efficient manner.
• Ability to evolve: Permit effective development, testing and introduction of new system functions without interfering with service.

The functions of OS are:

• Facilitate creation and modification of program and data files through an editor program

• Provide access to compilers to translate programs from high-level languages to machine language

• Provide a loader program to move the complied program code to the computer’s memory for execution,
• Assure that when there are several active processes in the computer, each will get fair and non-interfering access to the central processing unit for execution (scheduling)
• Provide routines that handle the intricate details of I/O programming
• Take care of storage and device allocation
• Provide for long term storage of user information in the form of files
• Permit system resources to be shared among users when appropriate, and be protected from unauthorized or mischievous intervention as necessary.