System Software

Chapter 5

The Director

© The McGraw-Hill Companies, Inc., 2000

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Overview

• System software

• Applications software

• System software components

• Platforms

• Web and Java

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What is system software and applications software?

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System Software

• Works behind the scene– starts up computer– provides interface between the machine

language the computer understands and hardware and applications

– system software must be loaded into RAM at start up

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Applications Software• Designed for user’s requirements

– word processing– spreadsheets– database management– graphics– multimedia

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Applications Software

• Productivity software– word processing, spreadsheet, financial

management, database management, communications, suites, browsers

• Business/specialty software• Education reference software• Home/personal software• Entertainment software

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Applications Software

• Has a user interface– communicates with other software

components such as the operating systems and application programming interface

• communicating to hardware

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Determine Needs Before Buying• What applications software do

you use?– word processing– browser– multimedia– graphics– financial management– database management

• Choose a computer system based on software requirements

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System Software Components

• What functions does system software perform?

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Basics

• Interprets data and instructions

• Communicates with peripherals

• Manages files

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System Software Components

• Operating system

• Utilities

• Language translators

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OS

• Master programs– supervisor in RAM– auto loads during boot routine using the master

boot record on the primary hard disk– POST performed

• Software interfaces to hardware frequently remain resident

• BIOS manages keyboard, screen, drives, ports, time, and date

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OS

• BIOS stored on one or more ROM chips

• Later editions of BIOS may be flash updated according to motherboard manufacturer’s instructions

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Managing Programs and Data

• Multitasking (single user)– concurrent program

running– foreground and

background running

• Multiprogramming (multi-user)– concurrent use by

different users

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Managing Programs (continued)

• Time-sharing– time slicing tasks

• Multiprocessing– simultaneous processing of two or more programs by

multiple processors• coprocessing

• parallel processing, sharing memory– called fault-tolerant systems

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Memory Management

• Virtual memory– hard disk space

– when processor needs more RAM space, swaps data onto designated hard drive space

– improves flexibility but is slower than RAM which has direct access to the processor

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Drivers

• Handle I/O for specific hardware

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Utilities Programs

• Utilities better than those that are native to an operating system can be purchased

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System Software Utilities

• Types– backup: system, registry, e-mail, files– data recovery– virus protection– data compression– defragmentation

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Data Compression

• Lossy– loss of accuracy, high degree of

compression

• Lossless– retained accuracy but lower

compression ratios

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Lossy Compression

• JPEG– Joint Photographers Experts Group– video storage and editing but not for

transmission

• MPEG – Motion Pictures Experts Group– storage, editing, and transmission of video

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Lossless Compression

• PC– PKZIP, WINZIP .ZIP– ARC .ARC– PAK .PAK

• Mac– StuffIt .SIT– PackIt .PIT

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Frag and Defrag

• Fragmentation refers to the storage of a file in fragments in many areas on a disk

• Defragmentation is a utility process that endeavors to bring each file into one whole area within the disk, contiguously

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Language Translators

• These are the compilers and interpreters used to connect programs into machine language to communicate with the processor

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System Software Interfaces

• Command driven• Unix, Linux

• Graphical User Interface (GUI)• Microsoft:Windows 9x, Millennium/Neptune, NT,

and 2000

• MacOS

• GNOME interface to Linux

• use of icons, windows (little “w”), high use of keyboard and mouse

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GUI

• Generally, GUI runs on top of operating system to assist users

• Some memory is used to provide the GUI

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OS Platforms

• How does Windows 9x/Millennium/Neptune compare to other operating systems?

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Common OSs

• Mainframe– IBM MVS, VM, DEC VAX/VMS

• Midframe– IBM OS-400, Linux, Sun Solaris

• Network– Novell NetWare, Lotus Dominoes, Microsoft

Windows NT

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Common Microprocessor OSs

• Microcomputer– Microsoft Windows

9x/Millennium/Neptune– Microsoft Windows NT/2000– Linux– Apple MacOS

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Windows 9x/Millennium/Neptune

• The first customer 32-bit operating system

• Windows 98 and 98 SE provide support for printers, video cards, DVD, and USB

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Windows NT

• Network system

• Scalable to large local area network

• Multitasking, multiprocessing, multiuser

• Windows NT Workstation– 1-2 processors

• Windows NT Server– up to 32 processors

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Other Windows OSs

• Windows CE provides support for palmtop computers

• Windows Millenium, due third quarter 2000, could be the last stand-alone consumer version of Windows 9x, with Windows 2000 in various capabilities coming to the forefront

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OS/2 Warp

• OS/ 2 never established an installed base large enough to attract application developers

• Poor marketing, but still supported

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UNIX

• Portable and scalable

• Can handle large volumes, such as needed on large Web sites

• Strong in medium-to-large businesses

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Linux

• Linux emulates UNIX• Many UNIX programs have been ported to

Linux• Open development

– can recompile source code

• Single user and small to medium Web server support

• Since code written for 386, can rehabilitate older systems out of use

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NetWare

• Established network operating system with strong printer and application server functions

• Small business edition for up to 25 users priced under NT

• Can sustain e-mail traffic through IPX protocol

• NT gain in ground, but NetWare a strong base

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Web

• What is a network computer, and how does it involve the Internet and Java?

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Specialization• Isolation of customer

and corporate needs• Software versions by

operating systems• Emergence of accessing

applications and systems online not just web pages– idea of renting

applications only for time used

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Bloatware

• Large percentage of applications have features not used

• Network PC– approximates mainframe terminal– sometimes with limited additional capabilities– also called thin client

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Progress Issue: Bandwidth• Sun’s control of Java Virtual

Machine diminishing as computer companies provide optimized VM

• Bandwidth increasing substantially through cable, digital subscriber service (DSL) on telephone lines, and the potential of more low-level satellites

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Java

• Developed by James Gosling’s group at Sun

• Promise of compile-once, run everywhere not totally realized

• Becoming more universal as run times decrease

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Some Generalities

• UNIX and Windows NT on high-end workstations

• Mac still used for intensive graphics and desktop publishing

• While Linux will not run Microsoft Office, such programs as ApplixWare provides filters to Office 2000 files, so the incompatability is disappearing