1. Operating System 2 Overview

2. OPERATING SYSTEM OBJECTIVES AND FUNCTIONS

3. 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

4. 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

7. THE EVOLUTION OF OPERATING SYSTEMS

8. Serial Processing Simple Batch Systems Multiprogrammed Batch Systems Time-Sharing Systems

9. Serial Processing With the earliest computers, from the late 1940s to the mid-1950s, the programmer interacted directly with the computer hardware; there was no OS.These computers were run from a console consisting of display lights, toggle switches, some form of input device, and a printer. Programs in machine code were loaded via the input device (e.g., a card reader). If an error halted the program, the error condition was indicated by the lights. If the program proceeded to a normal completion, the output appeared on the printer.

10. Simple Batch Systems

11. Multiprogrammed batch system

12. Time sharing single user was inefficient, a large group of users together were not. the "state" of each user and their programs would have to be kept in the machine, and then switched between quickly. Ex: NEW — to name and begin writing a program OLD — to retrieve a previously named program LIST — to display the current program SAVE — to save the current program RUN — to execute the current program

14. Five major theoretical advances 1. Processes  A program in execution  An instance of a program running on a computer  The entity that can be assigned to and executed on a processor  A unit of activity characterized by a single sequential thread of execution, a current state, and an associated set of system resources 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

15. Five major theoretical advances 2. Memory management Process isolation Automatic allocation and management Support of modular programming Long-term storage

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

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

20. MICROSOFT WINDOWS OVERVIEW

21. TRADITIONAL UNIX SYSTEMS

23. Modern Unix & Linux

24. 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.

29. System calls: The system call is the means by which a process requests a specific kernel service. There are several hundred system calls, which can be roughly grouped into six categories: filesystem, process, scheduling, interprocess communication, socket (networking), and miscellaneous.Table 2.7 defines a few examples in each category.

30. System calls: The system call is the means by which a process requests a specific kernel service. There are several hundred system calls, which can be roughly grouped into six categories: filesystem, process, scheduling, interprocess communication, socket (networking), and miscellaneous.Table 2.7 defines a few examples in each category.

31. Selesai....