Introduction to Os
IT 2203 : Operating Systems
Chapter 1: Introduction
What Operating Systems Do Computer-System Organization Computer-System Architecture Operating-System Structure Operating-System Operations Process Management Memory Management Storage Management Protection and Security Computing Environments Open-Source Operating Systems
Saminda Premaratne
What is an Operating System?
A program that acts as an intermediary between a user of a computer and the computer hardware Operating system goals: Execute user programs and make solving user problems easier Make the computer system convenient to use Use the computer hardware in an efficient manner Improve overall system reliability Provide isolation, security and protection among user programs.
Why should I study Operating Systems?
Computer System Structure
Computer system can be divided into four components Hardware – provides basic computing resources CPU, memory, I/O devices Operating system Controls and coordinates use of hardware among various applications and users Application programs – define the ways in which the system resources are used to solve the computing problems of the users Word processors, compilers, web browsers, database systems, video games Users People, machines, other computers
Four Components of a Computer System
Operating System Definition
OS is a resource allocator
Manages all resources Decides between conflicting requests for efficient and fair resource use
Operating System Definition (Cont)
No universally accepted definition “Everything a vendor ships when you order an operating system” is good approximation But varies wildly “The one program running at all times on the computer” is the kernel. Everything else is either a system program (ships with the operating system) or an application program
OS is a control program
Controls execution of programs to prevent errors and improper use of the computer
Goals of an Operating System
Simplify the execution of user
Chapter 1: Introduction
What Operating Systems Do Computer-System Organization Computer-System Architecture Operating-System Structure Operating-System Operations Process Management Memory Management Storage Management Protection and Security Computing Environments Open-Source Operating Systems
Saminda Premaratne
What is an Operating System?
A program that acts as an intermediary between a user of a computer and the computer hardware Operating system goals: Execute user programs and make solving user problems easier Make the computer system convenient to use Use the computer hardware in an efficient manner Improve overall system reliability Provide isolation, security and protection among user programs.
Why should I study Operating Systems?
Computer System Structure
Computer system can be divided into four components Hardware – provides basic computing resources CPU, memory, I/O devices Operating system Controls and coordinates use of hardware among various applications and users Application programs – define the ways in which the system resources are used to solve the computing problems of the users Word processors, compilers, web browsers, database systems, video games Users People, machines, other computers
Four Components of a Computer System
Operating System Definition
OS is a resource allocator
Manages all resources Decides between conflicting requests for efficient and fair resource use
Operating System Definition (Cont)
No universally accepted definition “Everything a vendor ships when you order an operating system” is good approximation But varies wildly “The one program running at all times on the computer” is the kernel. Everything else is either a system program (ships with the operating system) or an application program
OS is a control program
Controls execution of programs to prevent errors and improper use of the computer
Goals of an Operating System
Simplify the execution of user