Chapter 4 The Power behind the Power System Software Chapter 4 The Power behind the Power

Chapter 4: Key Questions 4.1 What are the three components of system software? 4.2 What are the principal functions of the operating system? 4.3 What are some common desktop, network, and portable OSs? 4.4 What are the characteristics of device drivers and utility programs?

Three Components of System Software There are two types of software- application and system. There are three basic components of system software: Operating system Device drivers Utility programs

Three components of system Software Operating Systems Manage system resources: CPU, memory, I/O Control and monitor the execution of other programs Device Drivers Programs that are used to control peripheral devices Utility Programs Support and enhance existing programs File backup, disk de-fragmentation, etc.

Operating System: What It Does Booting process of loading an operating system into a computer’s memory CPU(memory) management the supervisor(kernel) remains in memory It directs other “nonresident”, programs Virtual memory: use hard disk as a logical extension of memory

Operating System: What It Does File management File: a program or data (audio, video, text) OS manages files on hard disks and other storages devices like CD-ROM, DVD, etc Provides file-related operations: Create, delete, copy, rename, folders (directories) for file management NOTE: use folders to organize your files

Operating System: What It Does Task Management Multitasking the execution of two or more programs by one user concurrently on the same computer with one central processor Multiprogramming the execution of two or more programs concurrently on a multiuser operating system Time-sharing a single computer processes the tasks of several users in round-robin fashion Multiprocessing processing done by two or more computers or processors linked together to perform work simultaneously Multitasking – the execution of two or more programs by one user concurrently on the same computer with one central processor Multiprogramming – the execution of two or more programs concurrently on a multiuser operating system Time-sharing – a single computer processes the tasks of several users at different stations in round-robin fashion Multiprocessing – processing done by two or more computers or processors linked together to perform work simultaneously – that is, precisely at the same time

Operating System: What It Does Formatting Prepare a disk (floppy disk, or hard disk) for store data and/or programs. Each disk must be formatted before it can be used, Hard disks: formatted by the manufacture, normally not done by end users Floppy disks: formatted by the manufacture or by end users

Different Operating Systems DOS Mac OS Windows 3.1, 95, 98, Me Network platforms Netware Windows NT/2000 Unix/Solaris Unix/Linux/FreeBSD Palm OS Windows CE/Pocket PC Platforms – the particular processor model and operating system on which a computer is based DOS – command driven user interface Mac OS – runs on Apple Macintosh Emulation software – allows software designed for one computer to run on another Windows 3.1, 95, 98, Me – easy to use GUI as compared to DOS 95/98 – today’s most popular operating system for desktop and portable microcomputers Microsoft Windows Millennium or WinMe – successor to Windows 95 and 98; designed to support desktop and portable computers Network platforms Netware – popular on LANs Windows NT/2000 – multitasking operating system designed by Microsoft Unix – first to exploit the Internet Solaris – super-reliable version of Unix that seems to be most popular for handling large e-commerce servers and large Web sites Linux – free version of Unix Open-source software – any programmer can download it form the Internet for free and modify it with suggested improvements

Device Drivers Device drivers Three components for I/O devices: Programs that are designed to control input and output devices Three components for I/O devices: Device itself (scanner) - hardware Device controller (parallel card) - hardware Device driver designed for the OS -software Normally it is on a CD-ROM or a floppy disk Device drivers – programs that help the computer control a peripheral device Utility programs – programs used to support, enhance, or expand existing programs in a computer system; also known as service programs Backup – duplicate copy of information on your hard disk Data recovery – used to restore data that has been physically damaged or corrupted Virus protection Antivirus software – program that scans hard disks, floppy disks, and memory to detect viruses Data compression utilities – removes redundant elements, gaps, and unnecessary data from a computer’s storage space so that less space is required to store or transmit data File defragmentation – will find all the scattered files on your hard disk and reorganize them as contiguous files

Utility Programs Utility programs Backup – duplicate copy of data on your hard disk Data recovery – used to restore data that has been physically damaged or corrupted Virus protection Antivirus software – program that scans hard disks, floppy disks, and memory to detect viruses Data compression utilities – Compress the data so that less space is required to store or transmit data File defragmentation –reorganize files on your hard disk for better performance Device drivers – programs that help the computer control a peripheral device Utility programs – programs used to support, enhance, or expand existing programs in a computer system; also known as service programs Backup – duplicate copy of information on your hard disk Data recovery – used to restore data that has been physically damaged or corrupted Virus protection Antivirus software – program that scans hard disks, floppy disks, and memory to detect viruses Data compression utilities – removes redundant elements, gaps, and unnecessary data from a computer’s storage space so that less space is required to store or transmit data File defragmentation – will find all the scattered files on your hard disk and reorganize them as contiguous files