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Unit 1 OPERATING SYSTEM
After completing this lesson, you will be able to:
Define operating system
Describe commonly used operating systems
Explain the following types of operating systems
Batch Processing Operating System
Multiprogramming Operating System o Multitasking Operating System
Time-sharing Operating System
Real-time Operating System
o Multiprocessor Operating System
⚫ Parallel Processing Operating System
o Distributed Operating System
Embedded Operating System
Define Single-user and Multi-user Operating Systems Describe the following main functions of operating system
⚫ Process Management
Memory Management File Management
1/0 System Management
Secondary Storage Management
Network Management
Protection System
Command Interpreter
Define Process
Describe new, running, waiting/blocked, ready and terminated states of a process
Differentiate between the following.
Thread and process
Multi-threading and multitasking
Multitasking and multiprogramming.
1.1 INTRODUCTION
An operating system is the most important software that runs on a computer. It manages the computer’s memory and processes, as well as all of its software and hardware. It also allows users to communicate with the computer. Without an operating system, a computer user cannot run any program on the computer. It automatically loads in RAM when the computer is turned on. Operating systems exist from the very first computer generation and keep evolving with time.
1.1.1 OPERATING SYSTEM
An Operating System (OS) is a program that controls the execution of application programs and acts as an interface between the user of a computer and the computer hardware.
Every desktop computer, tablet, and smartphone includes an operating system that provides basic functionality for the device. Common desktop operating systems include Windows, OS X, and Linux.
Operating system performs the following tasks.
⚫ Loads application/system software into main memory and executes it.
⚫ Controls the operation of main memory and external storage devices.
■ Manages files and folders on storage devices such as hard disk, USB flash drive, etc. • Manages the operations of all the input/output devices.
⚫ Allows multitasking to handle several tasks at the same time such as running a spreadsheet software and a word-processor simultaneously.
• Performs network operations which enable a number of users to communicate with each other in a network environment and share computer resources such as CPU, main memory, hard disk, printer, Internet, etc.
⚫Detects hardware failures.
• Provides security through username and password.
1.1.2 COMMONLY USED OPERATING SYSTEMS
The commonly used operating systems are DOS, WINDOWS, Macintosh’s OS X/OS2 and UNIX/LINUX.
