Computer Software 1

7/27/2019 Computer Software 1

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Computer Software

Organized collection of computer data andinstructions responsible for controlling,

integrating and managing the hardwarecomponents and to accomplish specifictasks.


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Software Application software

programs primarily for users ( word processors,spreadsheets, databases, presentation graphics, etc.)

System software primarily used to run the computer ( operating

system, device drivers, assemblers, compilers ) intermediary between the users and hardware, hides

complex internal structure If system software is stored on non-volatile memorysuch as integrated circuits, it is usually termed

firmware


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The Role of System Software


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Types of system software System Management Programs

Responsible for the management and accurate functioningof the computer system

Manages operations of processor Manage Storage resources Controls I/O Provide support to execute application programs OS, Device drivers, System Utilities

System Development Programs Associated with the development of computer programs Programming languages, Language translators, Linkers and

Loaders


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System Management Programs Operating Systems

Set of integrated programs Manages overall performance and functioning of

computer Provides an interface between machine and user stored on non-volatile memory such as integrated circuits Eg DOS, Windows

Device drivers Programs responsible for proper functioning of devices Every device or hardware has a program for support Block device drivers and Character device drivers


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System ManagementPrograms(continued)

System Utilities Performs day-to-day tasks related to maintenance Usually provided along with the operating system

Common system utilities File management Backup Data recovery Virus protection Disk management Firewall Disk cleanup


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System Development Programs Programming Languages

Includes series of commands used in development of software Machine, Assembly and High Level Languages

Language translators

Helps in converting programming language instructions intomachine language Three types

Compiler convert the higher level language in lower level language. reads a whole block of code at a time, converts it into executable code, and

runs the code initial start up time to run program is more as compared to Interpreter Once the code is compiled, then the initial start up time to run the program is

negligible Languages like C, C++ are compiler based languages


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System DevelopmentPrograms(continued)

Interpreter converts the higher level language in lower level language or assembly language or binary

language reads one line of code at a time, converts it into binary language and then runs the code If there is any error on the middle of the program then the program is interrupted in between After removing the error the programs needs to run again from the beginning Languages like BASIC is interpreter based

Assembler takes computer instructions and converts them into a pattern of bits that the computer can

understand and perform it by certain operations translates assembly language to machine code Hardware dependent system software supplied by computer manufacturer

Linkers Program that links together several object modules and libraries to form a

single executable program Loaders

Responsible for relocation of the executable program in the main memory


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System Software (contd):

Loader: A loader is the part of an operating system that isresponsible for loading programs into memory, preparingthem for execution and then executing them.

The loader is usually a part of the operating system's kerneland usually is loaded at system boot time and stays inmemory until the system is rebooted, shut down, or poweredoff.

In Unix, the loader is the handler for the system call execve() .


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Linker: A linker or link editor is a program that takes one ormore objects generated by compilers and assembles theminto a single executable program.

Linkers can take objects from a collection called a library . Theobjects are program modules containing machine code andinformation for the linker.

The linker takes care of arranging the objects in a program'saddress space.


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Interpreter: An interpreter is a computer programthat translates and executes instructions written in acomputer programming language line-by-line, unit byunit etc.,

An interpreter needs to be able to analyze, or parse,instructions written in the source language.

Example: Lisp systems, etc.,


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Application software Designed to do specific task Can be used for a variety of reasons

as a business tool To assist with graphics multimedia projects

To support personal and educational activities To facilitate communication To aid in entertainment industry

General purpose application software Pre-written s/w designed for a variety of applications Excel, MS-word etc.

Tailored made software Developed for a particular client to address a special need


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Types of Application SoftwarePackages

Word processor Spreadsheet Database management system

Accounting programs Presentation tools Desktop publishing Multimedia applications Telecommunications software Web Browsers


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Word Processing

Uses Memos Reports

Correspondence Minutes of meetings Anything to be typed

Functions Create Edit Format Store Print text and graphics


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Desktop Publishing

Uses Newsletters Reports Brochures

Functions Handles high-level publishing needs


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Electronic Spreadsheets

Uses Comparing mortgage interest rates

Preparing budgets Tracking weight loss Functions

Manipulates numbers in rows and columns

Recalculates the results when a number ischanged What if?


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Electronic Spreadsheets


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Database Management

Uses Keep track of a large number of related facts Query the data for specific information Retrieve information in a variety of ways

Functions Store data Update data Manipulate data Retrieve data Print data in many forms Report on data in a variety of ways


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Graphics Uses

Maps Graphs Charts

Helps to Compare data Spot trends

Make decisions Visual information is more compelling


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Presentation Graphics

Uses Sales tool Demonstrate a product Show cost/benefit projections on charts Present audio/video testimonials from satisfied

customers May contain

Text Graphics Audio Video


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Computer Art Use software to

Produce art Express ideas

Graphic artist Artistic ability Computer skills Produces computer art


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Communications

Communicate from home with computer at office

Access data stored in another computer in another location

Stock exchange updates Weather information


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Communications

Provides method for communicating

between computers Most likely way to

connect is via theInternet

Use a browser toaccess the Internet


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Some common Software terms Firmware

Software written permanently onto ROM. Eg:BIOS Liveware

Human beings who write programs, operate and maintain the computer Freeware

Copyrighted software given away for free but no modifications are allowed Shareware

Comes with permission for people to redistribute copies for a limited period Public-domain software

Programs that are not copyrighted Commercial software

Developed by business organisations to earn profits from its use

Proprietary software Its use, redistribution or modification is prohibited or restricted Semi-free software

Comes with permission for individuals to use, copy, distribute , and modify for non profitpurposes


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Acquiring Software Freeware

Free to all Copyrighted

Distributed in machine-readable format Shareware

Freely distributed for a trial period Pay a nominal fee to register with the author


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Acquiring Software

Public-domain software Un-copyrighted May be used or altered without restriction Generally developed under government

grants Open-source

Free to all Source code is distributed May be used or altered Popular under the LINUX OS


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Acquiring Software

Commercial software Used most often

Copyrighted Generally costly May not be copied without permission of

the manufacturer


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Objectives Distinguish between operating systems and

applications software List the various methods by which individuals and

businesses acquire software List and briefly describe various types of task-

oriented software Identify the kinds of software available for both large

and small businesses Discuss ethical issues associated with software Describe the functions of various computer

professionals

Computer Software 1

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