Operating System 2 Overview OPERATING SYSTEM OBJECTIVES AND

Operating System 2 Overview

OPERATING SYSTEM OBJECTIVES AND FUNCTIONS

An OS is a program that controls the execution of application programs and acts as an interface between applications and the computer hardware. Objectives: ¨Convenience ¨Efficiency ¨Ability to evolve

Briefly, the OS typically provides services in the following areas: ¨ Program development ¨ Program execution ¨ Access to I/O devices ¨ Controlled access to files ¨ System access ¨ Error detection and response ¨ Accounting

THE EVOLUTION OF OPERATING SYSTEMS

Serial Processing n Simple Batch Systems n Multiprogrammed Batch Systems n Time-Sharing Systems n

Five major theoretical advances 1. Processes • Three major lines of computer system development created problems in timing and synchronization that contributed to the development of the concept of the process: multiprogramming batch operation, time sharing, and real-time transaction systems • problems: Improper synchronization, Failed mutual exclusion, Nondeterminate program operation, Deadlocks 2. Memory management • Process isolation • Automatic allocation and management • Support of modular programming • Long-term storage

Cont. . 3. Information protection and security • • Availability Confidentiality Data integrity Authenticity 4. Scheduling and resource management • • • Fairness Differential responsiveness Efficiency 5. System structure

Different approaches on os Microkernel architecture n Multithreading n Symmetric multiprocessing n Distributed operating systems n Object-oriented design n

MICROSOFT WINDOWS OVERVIEW

TRADITIONAL UNIX SYSTEMS

Modern Unix & Linux

n As UNIX evolved, the number of different implementations proliferated, each providing some useful features. There was a need to produce a new implementation that unified many of the important innovations, added other modern OS design fetures, and produced a more modular architecture.

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