National Diploma in Computer Studies Skill Area 310 Identify Software Categories Machine, Software and Program Design Prepared by Dhimas Ruswanto

Lecture Overview Computer Hardware Types of Software Software System Application Software

Computer Hardware CPU - Central processing unit Internal Memory External Memory CPU Processor Input Output ALU CPU - Central processing unit ALU - Arithmetic and logic unit ROM - Read only memory RAM - Random access memory

Hardware CPU - Brains of the computer Arithmetic calculations are performed using the Arithmetic/Logical Unit or ALU Control unit decodes and executes instructions Arithmetic operations are performed using binary number system

Hardware Memory – storage for input, temporary data and output: RAM – volatile (temporary), Hard Disk (semi-permanent).

Hardware I/O Devices Accessories that allow computer to perform specific tasks Receive information for processing Return the results of processing Store information Common input and output devices Speakers Mouse Scanner Printer Joystick CD-ROM Keyboard Microphone DVD Some devices are capable of both input and output Floppy drive Hard drive Magnetic tape units

Types of Software Systems Software Application Software General Purpose Application Software Special Purpose Software Bespoke or “off the shelf”

Systems Software Systems Software perform tasks that are needed to run on the computer systems Types of Systems Software: Operating System Library Programs Utility Programs (these are the programs designed to make life easier for computer users) Translation System

Operating Systems UNIX Set of programs containing instructions that control or maintain all the operations of a computer and its devices. Provides a means for users to communicate with the computer and other software. When a computer starts, parts of the operating system are copied into memory from the hard disk and remain in memory as long as computer is ON. Operating systems UNIX

Library Programs These programs are available to all users of a multi-user system to do tasks that are common and required by all For instance – a routine that searches for lost files, restores them, and saves them, is stored in a library.

Utility Programs Designed to make life easier for computer users. Example: Search for lost files Sort Files Copy onto a CD/magnetic disk Compress to a ZIP file

Translation System Set of programs used to develop software These are the basically the software that TRANSLATE the words of a high level program (such as C, C++, JAVA) to machine code to 1’s and 0’s A key component of a translation system is a translator Some types of translators Compiler Converts from one language to another Linker Combines resources Language Translation Process Source Program Machine Object Written in BASIC C,C++, etc. Translator Compiler Interpreter Assembler IF A := B THEN 1001101 1110101 0010110

Application Software Application software is the software that has made using computers indispensable and popular Common application software Word processors Desktop publishing programs Spreadsheets Presentation managers Drawing programs Types of Application Software based on Purpose: General purpose application software Special purpose application software

Generic Purpose Software Software Suites: Adobe Master Collections CS5 Microsoft Offices

Special Purpose Software Software to perform a specific task Examples: Software to help fill in an income tax return Stock Control System Payroll System

Bespoke Software This is software that is designed for a specific purpose AND for a specific organization. It is built specifically and custom-made for them Written to the exact specification of the customer Examples: Online Banking System Online Booking System

Off-The-Shelf Software Software which is not pirated A legal tender purchased from the store. Software which is not specifically designed for a customers requirements. Examples: AntiVirus Microsoft Windows

Bespoke vs. Off-The -Shelf Bespoke advantages: Designed to do exactly what the user wants Has no unwanted features Can be written to run on specific hardware Can be integrated with existing software There may not be a suitable software package on the market Off-the-shelf advantages: Less expensive More collaboration (can talk to other users of the software) Can be bought and installed immediately Software has been tried and tested – so will contain fewer bugs Software well documented Easily replaceable and can be found anywhere

Summary Computer Hardware: Types of Software: CPU, I/O Devices, Memory, Types of Software: Systems Software Application Software General Purpose Application Software Special Purpose Software Bespoke or “off the shelf