CSC491-lect09 week91 Software The computer programs that governs the operation of the computer Control the working of the computer hardware Computer program:

CSC491-lect09 week9 1

Software

• The computer programs that governs the operation of the computer

• Control the working of the computer hardware• Computer program: sequences of instructions for the

computer• Documentation: describe the program functions to

help the user operate the computer system• External resources:Printed manuals• Internal resources: help and support features


Types Of Software

• Two types of software: Systems software ,

application software • System software: set of programs designed to coordinate the

activities and functions of the hardware and various programs throughout of the hard

• Particular software package designed for specific CPU design

• Computer system platform: Combination of particular hardware configuration and system software package


Application Software

• Programs that help users solve particular computing problems

• Application software can support individuals, group, and organizations to help them achieve business objectives

• Application software can affect the processes that add value to a business, because it is designed for specific organizational activities and functions


• Goals and needs should be analyzed carefully before acquiring them for individual , group, or an enterprise

• Classification of uses of I.S. to identify the sphere of influence ,scope of the problems and opportunities addressed by a particular organization,


Personal sphere of influence• Personal sphere of influence: information systems that

serves the need of individual user• Personal productivity software: enables users to improve

their personal effectiveness, increasing the amount of work they can do and its quality

• Examples: word processing application, enter, check spelling,edit,copy,print, distribute and file text

• Spreadsheet: Excel, to manipulate numeric data for analysis and decision making

• Graphic application: to perform data analysis• Database: to organize data for personal use


Workgroup sphere of influence

• Two or more people who work together to achieve a common goal.

• Workgroup may be large, formal, permanent organizational entity such as department,section,temporary group

• Example:HR department of large organization• Workgroup sphere of influence: sphere of influence that

serves the needs of a workgroup• Examples: communication, interact ion, and collaboration

are critical to the success of the group• Information sharing, group scheduling, group decision

making, and conferencing


Enterprise sphere of influence

• Enterprise sphere of influence:that serves the needs of the firm in its interaction with its environment

• The environment consist of customers, suppliers, shareholders, competitors, financial community and government agencies

• Customers orders, inventory receipt and withdrawal ,purchase orders,invoices, and checks

• Examples: processing of employee time cards updates individual payroll records used to generate their checks

• Examples: order entry, finished product inventory,and billing information systems are examples of application


System Software

• Control computer hardware

• support application programs’ problem solving capabilities

• operating systems

• utility programs( disk cleanup, fragmentation…)


Operating Systems (OS)

• A set of computer programs that controls the computer hardware and acts as an interface with application programs

UsersApplication

software

OperatingAnd

System softwareHardware


• Stored on secondary memory and on disk also• Boot up ,portions of the OS are transferred to RAM as

they are needed• OS executes the following activities1. Perform common computer hardware functions

(start ,stop,input and output data from user,)2. Provide user interface (desktop, start, taskbar, icons)3. Managing system memory4. Managing processing tasks5. Providing networking capability6. Controlling access to system resources7. Managing files


Kernel

• The kernel is the most important part of the OS

• Controls the most critical processes

• Ties all of the components of the operating system together and regulates other programs


1:Common computer hardware functions

• All application programs must perform common tasks

• Get input from users through keyboard, or CD. Disk

• Store data on hard disk, floppy ,or CD.

• Display information on a monitor or printer

• the OS converts these basic instructions into more detailed set of instructions


2:User Interface• Users communicate with an operating system through the

user interface of that O.S.• Early PC operating system were command-driven• GUI: makes extensive use of icons, buttons,bars, and boxes

to perform same task• Advantage : users don’t need to remember text-based

commands and their syntax• Pull-down menus: select commands• Pop-up boxes: various command options• Graphical symbols themselves are not always easy to

understand, GUI should be well designed


3:Managing System memory

• The purpose of memory management is to control how memory is accessed and to maximize available memory and storage

• Which program has memory at what memory locations to provide it to CPU

• Computer only understands the physical view of data• Virtual memory:memory that allocates space on the hard disk

to supplement the immediate, functional memory capacity of RAM

• Paging:virtual memory works by swapping programs or parts of program b/w RAM and disk devices


4:Managing Processing tasks

• In a time sharing OS many processes use CPU time • Multitasking needs to be supervised by OS to allow

different program ,this is Scheduling• Move back and forth in RAM , update their changes• Schedule the use of input and output devices• Not all jobs are performed in the order they are

submitted• Processes have priority, higher priority jobs

executed first


5:Network Capability

• OS can provide features and capabilities that aid users in connecting to a computer network

• Example: Apple computer users have built-in network access through the AppleShare feature,

• and the MS windows OS come with the capability to link users to the Internet


6:Controlling access to system Resources

• Sensitive data should not be accessed over networks• OS needs to provide high level of security against

unauthorized access• Log-on procedure: identification code and a

matching password• OS requires users to frequently change password• OS records the activity of successful log-on• To bill users for time spent using the system• OS also reports any attempted breaches of security


7:File Management

• Different users have different files, OS make sure that authorized users have access to the files

• OS keep tracks of where each file is stored• Most Important: OS must be able to resolve what to

do if more than one user request access to the same file at the same time

• On single user PC,file management is needed to keep track where files are,size,time of creation and last accessed or modified,who created


PC Operating Systems

• PC software is based on specific OS and computer hardware

• PC OS have distinctive features– support multi tasking, graphics work that determine the type of Applications for which they are suited

• Older OS do not allow multitasking


Disk Operating System (DOS)

• DOS was the most popular OS for 16 bit PCs

• Still used because so much applications have been written for system using DOS

• DOS does not support multitasking

• Limit the size of a program in memory to 640 K

• DOS is command-driven

• Examples: delete | copy | filename.ext


MS Windows 95

• Launched programs appear at the task bar (normally positioned at the bottom of the screen)

• Clicking on any task bar button switches to that program

• Files are shown as icons within folders• Windows explorer: software that gives you a tree-

based view of your computer and its connections• Multitasking system• File names not restricted to eight characters / 255


Windows 98

• Improved version of 95

• Improved support for newer hardware devices(Pentium processors, network cards, images)

• Attempts were made to shorten the time to load from the hard disk drive

• System shutdown was also speeded up


Windows NT workstation

• Designed for newer 32-bit processors, multitasking , network capabilities

• Using emulation software, NT can run program written for other OS

• Example: NT trying to emulate Unix, some translation of code must happen before any program can be run on the emulator

• Different OS have different instruction sets• NT support simultaneous use of multiple processors• Built –in networking to support several comms. protocols• NT has a centralized security system to monitor resources


Windows NT workstation

• NTFS file system, enhances performance and reliability

• Windows NT Workstation also functions as a Web server

• Workstation users can tackle light publishing tasks with Personal Web Server (PWS)

• Powerful enough for use with a small workgroup over an intranet


Windows 2000

• Rename the next release of the Windows NT as Windows 2000

• 30 millions lines of code

• Took four years , cost $ 1 Billion to develop

• Desktop OS aimed at businesses of all sizes

• Was easiest to use Windows

• Designed for high reliability

• Laptop users were also a target feature


Unix

• Originally developed by AT&T for mini computers• Can be used on many computer system types and

platforms• PC to mainframe systems• It is compatible with different type of hardware ,

users have to learn only one OS• Move programs and data among computers or to

connect mainframes and PC to share resources• Has a complex user interface


Unix

• Software developers have provided shells such as Motif from Open System Foundation and

Open Look from Sun Microsystems.

• These shells do what older versions of Windows did for DOS

• Many variants of Unix, HP/UX from HP

• AIX from IBM, Solaris from Sun Microsystems


Linux

• Linux is a free Unix-type OS does not come from the same source code base

• Created by Linus Torvalds at University of Helsinki with the assistance of developers around the world

• Developed in 1991 version 0.02• Linux is only the kernel of the OS• Kernel: the part that controls hardware, manages files,

separates processes…• Several combination of OS=Linux + utilities+ application• Each is called distribution of Linux


• The biggest shortfall for Linux is the scarcity of application programs written for the OS

• The availability of service and support is also a concern

• Vendors ,Red Hat offer Linux software packages with integrated tools, removing many of the do-it-yourself headaches of a downloaded OS

• Red Hat Linux 6.1 is a network OS from Red Hat Software


Solaris

• Sun Microsystems variation of the Unix OS

• Server OS for large Web sites

• Highly reliable

• Can supervise servers with as many as 64 microprocessor

• Fault detection, a unique feature, processor getting too hot


Apple Computer OS

• Use Motorola Processors and Apple OS– MAC• Mac OS 9: began 1999• Sherlock 2 feature of MAC OS9 is personal search

detective and personal shopper• Multiple users feature, safely share MAC computer

with other people• MAC OS X: January 2000 preloaded as standard OS

on all Macintosh computers• New UI. “Aqua”


Workgroup Operating Systems

• Internet usage is primary consideration, Networking, security is the targeted features

• Scaling is also pushing the boundaries of computer science• Need more powerful OS


Windows 2000 Server

• Updated to the Windows desktop

• Most important changes are in the version for server computers that manage corporate networks, run application such as accounting , email, and serve up Web pages from company site

• Based on Windows NT, but more reliable

• Web sites and corporate Web applications that run on the Internet


Netware

• It is a Network operating system sold by Novell .

• Supports Windows , Mac , and Unix

• Provide directory software to keep track of computers, programs, and people on a network

• NDS (Novell directory software) runs on Windows 2000, Solaris, and Linux servers


Enterprise Operating Systems

• Windows NT, Windows 2000, Solaris and other workgroup OS have version that are extremely powerful, can meet enterprise computing needs

• In spite of this, mainframe computers have their own

application

• CMOS (complementary metal oxide semiconductor) technology provide smaller, faster, and less expensive systems

• Larger number of users with high performance, strong security, scalability

• Still number 1 choice for mission-critical business application for many companies


OS/390

• IBM S/390 mainframe computers transformed by introducing parallel servers

• Again CMOS, causing less cost, high performance

• New generation OS/390 server operating system

• Evolution of IBM mainframe OS called MVS first developed in 1960s


Utility Programs

• Used to merge and sort sets of data, keep track of computer jobs being run, compress file of data before they are stored or transmitted over a network

• Utility programs often come installed on computer system

• Norton Utilities: for example, is a set of utility programs, checking hard drive , diskettes for viruses, bad sectors,locating and removing

Documents

CSC491-lect09 week91 Software The computer programs that governs the operation of the computer Control the working of the computer hardware Computer program: