Using Information Technology

Chapter 4System Software

System SoftwareThe Power behind the Power

4.1 The Components of System Software

4.2 The Operating System: What It Does

4.3 Other System Software: Device Drivers & Utility Programs

4.4 Common Operating Systems

4.5 The OS of the Future: “The Network is the Computer”

4.6 Online Software & Application Software Providers: Turning Point for the Software Industry?

System Software

System software enables the application software to interact with the computer and helps the computer manage its internal and external resources.

4.1 The Components of System Software

Operating system - the principal component of system software

Device drivers - help the computer control peripheral devices

Utility programs - support, enhance, or expand existing programs

4.2 The Operating System: What It DoesOperating System – Also called Software platform – consists of the master system of programs that manage the basic operations of the computer.

Different sizes of computers, main, mini etc and different platforms have different operating system.

E.g. MS Windows XPMS Windows 2000 ProfessionalMS Windows 2003 Advanced ServerLinux ( various vendors … Red Hat popular)Free BSDSymbian OS

Basic Tasks of Operating System

BootingUser InterfaceCPU ManagementFile ManagementTask ManagementFormattingSecurity Management

BootingThe process of loading an operating system into a computer’s main memory.

In addition diagnostic routines are also run at the time of booting.

Cold boot Switch ON the PC

Warm boot ALT+CTRL+DEL or reset the PC

User interface

User-controllable display screen that allows you to communicate, or interact, with your computer

CPU Management Supervision and Management of Activities

Memory Management

The supervisor, or kernel, manages the CPU. It remains in main memory while the computer is running and directs other "nonresident" programs (programs that are not in main memory) to perform tasks that support application programs.

Memory management

Partitioning – In partitioning, the OS divides memory into separate areas called partitions, each of which can hold a program or data.

Foreground/background – Some computer systems divide memory into foreground and background areas. Foreground programs have higher priority, and background programs have lower priority.

Queues – Programs that are to be executed wait on disk in queues. A queue is a temporary holding place for programs or data.

File ManagementFiles of data and programs are located in many places on your hard disk and other secondary-storage devices. The operating system records the storage location of all files to helps you locate and gain access to it. Following are the key function of file management:-

Move

Rename

Delete

Copy

Back up

Task Management

A computer is required to perform many different tasks at once. A "task" is an operation such as storing, printing, or calculating. Among the ways operating systems (not all) manage tasks in order to run more efficiently are:

Multitasking Multiprogramming Time-sharing Multiprocessing

Multitasking

The execution of two or more programs by one user concurrently on the same computer with one central processor.

Because the processor is usually very fast, it may appear that all the programs are being executed at the same time. However, the processor is still executing only one instruction at a time.

Only one program is running at any given instant of time

Multiprogramming

The execution of two or more programs concurrently on a multi-user 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.

Two Approaches for Multiprocessing:-Co processing

One main CPU works together with other specialized microprocessors… like Math Coprocessor is present in every PC

Parallel Processing Multiple CPU’s… Dual CPU PC’s etc

The Operating System: What It DoesTask Management

Number of Users

Number of Processors

Order of Processing

Multi-tasking One One Concurrently

Multi-programming

Multiple One Concurrently

Time sharing Multiple One Round robin

Multi-processing

One or more

Two or more

Simultaneously

Processing of two or more programs

Formatting

Initializing a disk - the process of preparing that disk so that it can store data or programs

4.3 Other System Software

Device Drivers Utility Programs

Device Drivers

Specialized software programs that:

(a) Allow input and output devices to communicate with the rest of the computer system.

(b) Help the computer control peripheral devices.

Peripheral DevicesPeripheral, is a term used for devices, such as disk drives, printers, modems, and joysticks, that are connected to a computer and are controlled by its microprocessor.

Although peripheral often implies “additional but not essential,” many peripheral devices are critical elements of a fully functioning and useful computer system. Few people, for example, would argue that disk drives are nonessential, although computers can function without them. Keyboards, monitors, and mice are also strictly considered peripheral devices, but because they represent primary sources of input and output in most computer systems, they can be considered more as extensions of the system unit than as peripherals.

Utility ProgramsAlso known as service programs, perform tasks related to the control and allocation of computer resources. They enhance existing functions or provide services not supplied by other system software programs. Among the tasks performed by utilities are the following:

• Backup• Data Recovery• Virus Protection• Data Compression• File defragmentation • Disk Scanner

Backup Utility

Program which makes a duplicate copy of the information on your hard disk.

If your hard-disk drive fails, and you have used a backup utility to make a backup, you can restore the information on your hard disk.

Data Recovery Utility

Program which restores data that has been physically damaged or corrupted.

Data can be damaged by viruses, bad software, hardware failure, and power fluctuations that occur while data is being written/recorded

Virus Protection Utility – Antivirus software

A program that scans hard disks, floppy disks, and memory to detect viruses.

A virus consists of hidden programming instructions that are buried within an applications or systems program. Fortunately, antivirus software is available. Antivirus software is a utility program that scans hard disks, floppy disks, and memory to detect viruses. Some utilities destroy the virus on the spot. Others notify you of possible viral behavior.

Data Compression Utility

A program which removes redundant elements, gaps, and unnecessary data from a computer’s storage space.

As you continue to store files on your hard disk, it will eventually fill up. Data compression utilities remove redundant elements, gaps, and unnecessary data from a computer’s storage space so that less space (fewer bits) is required.

File Defragmentation Utility

Fragmentation - the scattering of portions of files about the disk in nonadjacent areas, thus greatly slowing access to the files

Defragmenter utility - program that finds all the scattered files on your hard disk and reorganizes them as contiguous files

File Defragmentation Utility

When a hard disk is new, the operating system puts files on the disk contiguously (next to one another). However, as you update a file over time, new data for that file is distributed to unused spaces. These spaces may not be contiguous to the older data in that file. It takes the operating system longer to read these fragmented files. A defragmenter utility program, commonly called a "defragger," will find all the scattered files on your hard disk and reorganize them as contiguous files.

Disk Scanner & Disk cleanup Utility

Detect and correct certain types of common problems on hard disks and floppies

Search for and remove unnecessary files, such as temporary files.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

4.4 Common Operating Systems for Various Platforms

Platform - the particular processor model and operating system on which a computer system is based.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Disk Operating System (DOS)

The original operating system produced by Microsoft, which had a hard-to-use command-driven user interface

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Macintosh operating system (Mac OS)

Operating system which runs only on Apple Macintosh computers . First introduced in 1984, set the standard for icon-oriented, easy-to-use graphical user interfaces.

Mac OS X

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Microsoft Windows 3.1 & 3.X

In the1980s, taking its cue from the popularity of Mac’s easy-to-use GUI, Microsoft began working on Windows--to make DOS more user-friendly. In 1992, Windows 3.1 emerged as the preferred system among PC users. Technically, Windows 3.1 wasn’t a full operating system; it was simply a layer or shell over DOS.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Microsoft Windows 95, & 98

Later, Windows 3.1 evolved into the Windows 95 operating system, which was succeeded by Windows 98. Both having Plug and Play - the ability of a computer to automatically configure a new hardware component that is added to it

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Microsoft Windows Millennium (WinMe)

Is the successor for home users to Windows 95 and 98, designed to support desktop and portable computers.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

Novell’s NetWareWindows NT/2000Windows XP / VistaUnixLinux

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

Novell’s Netware - a long popular network operating system for coordinating microcomputer-based local area networks (LANs) throughout a company or campus

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

Windows NT - Microsoft’s multitasking OS designed to run on network servers; it allows multiple users to share resources such as data and programs

Windows 2000 - successor to Windows NT

Windows XP –

Windows Vista

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

Windows XP - Formerly code-named Whistler, Microsoft’s newest OS, which combines elements of Windows 2000 and Windows Me

New GUI featured in Windows XP

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

UNIX was initially developed by AT&T’s Bell laboratory in 1969 as operating system for minicomputers.

UNIX - a multitasking operating system for multiple users with built-in networking capability and versions that can run on all kinds of computers.

Variants of Unix for Internet:-

• Sun Microsystems’ Solaris

• Berkeley Software Distribution (BSD)

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

Linux – an Open Source free version of UNIX, with continual improvements resulting from the efforts of tens of thousands of volunteer programmers

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Operating Systems

Open-source software - software which any programmer can download from the Internet for free and modify with suggested improvements Linus Torvalds, creator of

Linux

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Operating Systems for Handhelds

Palm OS - the dominant OS for handhelds, which runs the Palm and Handspring Visor, and is licensed to other companies, such as IBM and Nokia.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Operating Systems for Handhelds

Windows CE/Pocket PC--Microsoft Windows for handhelds: In 1996, Microsoft released Windows CE, a greatly slimmed-down version of Windows 95 for handheld computing devices, such as those made by Casio, Compaq, and Hewlett-Packard. Windows CE had some of the familiar Windows look and feel and included rudimentary word processing, spreadsheet, e-mail, Web browsing, and other software.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

4.5 The OS of the Future: “The Network is the Computer”

Dot Net – .Net is Microsoft’s platform for an OS for the entire Internet, designed to link unrelated websites so that people can organize all info in their lives using PCs and smaller devices

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

The OS of the Future

E-speak - H-P’s version of an Internet OS, or “universal language,” that allows different websites to communicate with one another

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

The OS of the Future

Jini - Sun Microsystems’ software designed to let all types of electronic gadgets on a wired or wireless network communicate with one another.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

The Opposite Possibility: No One Company Dominates

Distributed system - a non-centralized network consisting of several computers and other devices that can communicate with one another

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

4.6 Online Software & Application Software Providers: Turning Point for the Software Industry?

ASP (Application Service Provider) - a firm that leases software over the Internet to customers.

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

Network Computers Revisited: “Thin Clients” versus “Fat Clients”

Thin client - users download not only data but also different kinds of application software from an online source

Network Computers Revisited: “Thin Clients” versus “Fat Clients”

Data can be input or downloaded from online sources.

Fat client - users provide their own software and are usually responsible for any upgrades of hardware and software

Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.

From ERP to ASP: The Evolution of “Rentalware”

ERP (Enterprise resource planning) software - large client/server software applications that help companies organize and operate their businesses