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

2. 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?

3. 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

4. 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.

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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