Introduction-ch1 - Bilkent University Department of...

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1 Chapter 1 Introduction Dr. İbrahim Körpeoğlu Last Update: Jan 25, 2016 Bilkent University Department of Computer Engineering CS342 Operating Systems
2 Outline and Objectives Outline What Operating Systems Do Computer-System Organization OS structure and operation Major OS Functions Process Management Memory Management Storage Management Protection and Security Computing Environments Objectives To provide a grand tour of the major operating systems components To provide coverage of basic computer system
3 Basic components of a computer system: place of OS A 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 –solve the problems of the users: use system resources Word processors, compilers, web browsers, database systems, video games Users People, machines, other computers
What is an operating system? Application User/ Application
4 Operating system functionalities/goals Start/terminate/control executing user programs Make system convenient to use Control and coordinate use of hardware Perform I/O; setup devices Allocate resources ( so that it can operate the computer system efficiently and fairly ) Use hardware efficiently Implement common services Application OS HW CPU, Memory, Devices
5 Operating System Definition No universally accepted definition “Everything a vendor ships when you order an operating system” is good approximation But varies wildly Kernel : running all the time; having most of the functionality Everything else: either a system program (ships with the operating system) or an application program system programs (Some application programs) OS CD kernel System programs : programs that are associated with the operating system + you can install other applications
6 Computer System Organization and Operation
7 Computer System Organization Computer-system operation One or more CPUs , device controllers connect through common bus providing access to shared memory Concurrent execution of CPUs and devices competing for memory cycles Network adapter Network cable Bus
8 Computer Startup bootstrap program is loaded at power-up or reboot Typically stored in ROM or EPROM, generally known as firmware Initializes all aspects of the system Loads operating system kernel and starts execution Kernel runs and make the system ready for running applications Kernel is always ready to run (always in memory)
9 Computer system operation: I/O and device interaction I/O devices and the CPU can execute concurrently Each device controller has a local buffer

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