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Computer Software Bayram Güzer Software • Software is the planned, step-by-step set of instructions required to turn data into information that makes the computer useful. • Generally software can be categorized as – Application software – System software • Application software is used to solve a particular problem or perform a particular task • Examples; – – – – Keeping track of store inventory Designing a car engine Draft the minutes of the meeting Playing a game 2 Software • System software is the all programs related to coordinating computer operations • Examples; – Operating systems – Language translators • Convert program code to machine-readable form – Utility programs • Perform secondary tasks (everyday jobs) 3 Operating System • A set of programs that lies between application programs and the hardware – Manages computer’s resources (CPU, peripheral devices) – Establishes a user interface • Determines how user interacts with operating system – Provides and executes services for applications software 4 Kernel • The most important program in the operating system is the program that manages the operating system which is called as supervisor program or kernel. – It is loaded from hard drive into memory when computer is booted • Booting refers to starting the computer – Since it remains in memory permanently until power loss it is also referred to as resident. – It loads other operating system programs from disk storage as needed that is referred to as nonresident. 5 Operating Systems for Personal Computers • Platform is combination of computer hardware and operating system software – Wintel (Microsoft Windows running on an Intel-based PC) is most common • Common Operating Systems – Windows – MAC OS – Linux 6 MS-DOS • Uses a command-line interface – Screen provides prompts for user – User types commands • Largely replaced by graphical user interfaces • Not user-friendly 7 Microsoft Windows • Began as an operating environment for MS-DOS – Not a full-blown operating system; required MS-DOS • Uses a graphical user interface (GUI) – Users can use DOS commands and interface • Now a complete family of operating systems 8 Windows 3.1 • Windows 3.1 is also known as the MS-DOS Operating Environment • A layer added “on top” of DOS – Separates operating system from user – Makes operating system easier to use • It is also called as a shell – A shell is a piece of software that provides an interface for users. Typically, the term refers to an operating system shell which provides access to the services of a kernel 9 Graphical User Interface (GUI) • Graphical user interface is the environment which users work with on-screen pictures called icons and menus rather than keyedin commands. • User clicks an icon to perform tasks • There is a start Menu in lower left corner which launches programs • You can use menus to activate commands 10 Windows Features • Long file names (up to 255 characters) • Plug and Play – Makes installing hardware components easier – A user can install it simply by plugging it in and turning on the computer. • Object Linking and Embedding (OLE) – Allows user to embed or link one document to another • Embedding graphics into document and editing graphic within a document. 11 The Windows Family • Windows 9x – – – – Windows 95 Windows 98 Windows Millennium Edition (ME) Windows CE • Corporate Market – Windows NT – Windows 2000 • Windows XP • Windows Vista • Windows 7 12 Windows 9x • Serves home/consumer market • No longer a shell, but a self-contained operating system • Began with Windows 95 – Next Generation: • Windows 98 • Windows ME • Many improvements over Windows 3.1 13 Windows 98 Improvement • Internet/intranet browsing capabilities have been improved. • Support for state-of-the-art hardware, including DVD and multimedia are enriched. • Support for huge disk drives is provided. • Wizards: step-by-step software for installing, configuring, and using software easier. 14 Windows ME Enhancements • Multimedia support: Media Player, video editing • Enhanced reliability features • Home network support 15 Windows CE • Scaled-back version of Windows 9x – Designed to work on machines with small screens and little storage • Used in Pocket PCs • Used in embedded systems – Computer devices integrated into other products; i.e., robots • CE.NET supports .NET platform 16 Corporate Market • Windows NT – NT stands for “new technology” • Windows 2000 17 Windows NT • Desktop looks and acts like Windows 98 • Meant mostly for corporate, networked environments – Engineered for scalability (the ability to handle many users) – Stronger security features – It requires much more memory and hard disk space than Windows 98. 18 Windows 2000 • The latest generation of Windows NT • Merges Windows NT 4.0’s stability with Windows 98’s setup and hardware awareness. • Dynamic layout features will detect what kind of screen you are on (handheld, TV, PC). • One computer “serves” many users – You identify yourself and the system knows your preferences – You get “your” desktop and files, regardless of which PC you use to log into the network 19 Windows XP • Brings consumer and corporate versions of Windows together into a single product – Has Home and Professional Editions • Enhancements 20 Windows XP Enhancements • Improved user interface – Much clearer and uncluttered desktop – More icons on redesigned Start Menu • Improved multimedia support • More personalization • Multiple user support – User can log off, leaving programs running, and allow another user to log on – Set up limited accounts for children to use; i.e., no inappropriate games or no Internet access • Internet support and protection 21 Windows Vista • Windows Vista: Most recent version of Windows • Features the Aero visual interface – Transparency and animations – Live Thumbnails • • • • The Vista Start menu is more modernized Built-in security features Improved networking and multimedia Additional features – Sidebar, Instant Search, etc. • Hardware requirements for Vista have increased over earlier versions of Windows • Four editions (Home Basic, Home Premium, Business, and Ultimate) 22 Windows 7 • Designed to fix the Vista debacle; sort of a streamlined Vista under the hood • Faster boot/shutdown times • Some “improvements” to the UI, handling media, Windows Explorer, IE8, wireless networking and setting up home networks 23 MAC OS • Designed for the Macintosh computer • It is also known as the first commercially successful GUI – Has served as a model for Windows and other GUI products developed since Mac OS 24 UNIX • Developed in 1971 for use on the DEC minicomputer • Character-based system with command-line interface • Not tied to any family of processors – Runs on just about every type of system (PC, mainframe, workstation) from any manufacturer • Primary operating system in use on Internet servers – Handles many simultaneous users easily • Look for SCO Unixware/SCO Open Server for the latest version. 25 Linux • Uses command-line interface – Many companies have created a GUI to work with Linux • Open-source concept – Source code is free – Users can download, change, and distribute the software • • • • More stable than Windows Applications relatively limited Hardware compatibility is limited It is mostly used by advanced users/IT professionals 26 Operating Systems for Networks • A networking operating system is an operating system that contains components and programs that allow a computer on a network to serve requests from other computer for data and provide access to other resources such as printer and file systems. • Some of the NOS functions are; – Handles network functions – Make resources appear as though they were running from client computers 27 Network Functions • Common functions of the networks are listed below; – – – – Sharing resources (hard disks and printers) Providing data security Troubleshooting the network Administrative control of the network 28 Network Operating Systems • • • • Windows NT Server Windows 2000 Server Windows .NET Server (Windows Server 2003) Novell Netware – Novell Open Enterprise Server (OES) • OES-Linux • OES-Netware • Unix – SCO Unixware/SCO Open Server 29 Network Operating Systems • Unix-like – Minix – Solaris – Berkeley Software Distribution • Free BSD • Net BSD – Open BSD – Open Solaris – Linux 30 Network Operating Systems • Resource allocation is the process of assigning computer resources to certain programs and processes for their use • Main issues related to resource allocation – – – – Sharing the Central Processing Unit Sharing memory Sharing storage resources Sharing printing resources 31 Sharing the CPU • There are three ways for sharing the cpu; – Multiprocessing – Multiprogramming – Time-Sharing 32 Multiprocessing • Multiprocessing is the use of a computer with multiple CPUs • Symmetric multiprocessing – treats all of the processing elements in the system identically • Asymmetric multiprocessing – system assigns certain tasks only to certain processors • Reserving only one CPU to responding all hardware interrupts 33 Multiprogramming • Two or more programs executed concurrently – Programs take turns using the CPU – Event-driven • An interrupt suspends processing to allow another program to run • After the second program runs, the operating system returns the CPU to another program • Generally used for batch programs that do not require user input 34 Time-Sharing • Programs take turns using the CPU • Time-driven – Each user is given a slice of time (fraction of a second) – CPU works only on that user’s tasks during its time slice – Response time is the time between typed request and computer’s reply • Typically used in applications with many users 35 Sharing Memory • Sharing memory is related to memory management • It divides memory into foreground and background sections • It also uses virtual storage which is also called as virtual memory 36 Memory Management • Divides memory into separate partitions • Allocates memory to programs • Keeps programs separate from one another 37 Foreground and Background • Foreground is for programs with high priority that will receive more CPU time. • Background is for programs with lower priority that will receive less CPU time – Programs waiting to run are kept in queues based on their priority 38 Virtual Storage • Programs currently executed are stored on disk – Portions of program brought into memory as needed – Minimizes the amount of memory needed • Can be implemented by paging – Divide memory into small, fixed-size pages – Page table keeps track of memory locations 39 Sharing Storage Resources • Keeps track of location of files • Responds to commands to manipulate files on the main computer. • Keeps track of input and output requests for files – Processes them in the order received 40 Sharing Printing Resources • Spooling is the process in a program which writes a line to a disk file rather than sending directly to a printer – When file is completed, it is placed in queue – File is printed when printer becomes available • Allows program to complete execution much more quickly – Writing to disk is much quicker than writing to printer 41 Utility Programs • Perform secondary tasks • Examples – File manager – File compression – Others 42 File Manager • Stores files in a hierarchical directory structure • Windows uses Windows Explorer 43 File Compression • Reduces amount of space a file requires – Makes file take up less space on disk – Takes less time to transmit across communication lines 44 Other Utility Programs • Backup and Restore – Backup: make copies of disks and store in a safe place – Restore: restore files from backups • Disk defragmenter: reorganizes disk so all files are stored in contiguous locations • Device driver: handles commands for devices, such as printers and storage devices 45 Applications Software • Software used to solve a particular problem or perform a particular task 46 Acquiring Software: Traditional Ways • Custom software – Written by programmers hired by organization • Packaged (commercial) software – Purchased from a store, catalog, or Web site 47 Custom Software • Specifically tailored to an organization’s needs – Organization hires computer programmers to design, write, test, and implement software • Can be extremely complex and take years to write 48 Packaged Software • Sold in stores, catalogs, or Web sites – Sometimes downloaded from the Internet • Package contains one or more CDs or DVDs holding the software – Typically contains software documentation • Designed to be user-friendly 49 User-Friendly Software • Easy to use – Software should be sensitive for even a beginning user – Software can be used with minimum of training and documentation 50 Acquiring Software: New Ways • Freeware • Public Domain • Open-Source software • Shareware 51 Freeware • Author provides it free for all to use – Author keeps copyright – May place restrictions on its use – May not be altered or redistributed without permission 52 Public Domain • Software that is not copyrighted – May be used and even altered without permission • Typically developed by universities and/or research institutions using government grants 53 Open-Source Software • A variation of freeware • Source code made available – Source code: readable by humans • Other programmers can modify and redistribute the programs freely – Helps identify bugs and create improvements more easily 54 Shareware • Copyrighted software, freely distributed for a trial period • If you like it, register it for a fee – Most authors add free documentation, enhancements, support, and updates to encourage people to register 55 Buying Commercial Software • 4 ways for buying a commercial software; – – – – Individual copies for each computer Site license Electronic software distribution Application Service Provider 56 Site License • Software installed on some or all computers, depending on license terms – Customer keeps track of how many users • Number of users cannot exceed number of licenses – Customer copies and distributes software and manuals to users • Some organizations use network licenses – Software installed on server – License fee based on number of concurrent users 57 Electronic Software Distribution • Get software from the Internet – Typically freeware and shareware – Some commercial software • Typical scenario: – Download software for trial period – Software disables itself after trial period unless you register (pay) 58 Application Service Provider • Delivers applications to businesses via the Internet – ASP maintains software and data on its systems • Customers access applications as needed over the Internet – Alternative to creating and maintaining custom software or purchasing packaged software • “Rent” software, paying based on usage 59 Task-Oriented Software • Often called productivity software • Common categories – – – – – – Word processing/Desktop publishing Electronic spreadsheets Database management Graphics Communications Others 60 Working with Words • Word Processing – Most widely used personal computer software – Create memos, reports, papers – Incorporate graphics into documents • Desktop Publishing – Used for high-level publishing needs • Newsletters • Brochures, promotional materials 61 Electronic Spreadsheets • Made up of rows and columns of numbers • Perform “what if” analysis – Change a cell and have spreadsheet recalculate • Present data graphically – Show expenses as a pie chart 62 Database Management • Handles the management of a collection of interrelated facts – Software can store, retrieve, update, and manipulate data – Can report data in many ways and print • Turn large amounts of data into information 63 Graphics • Graphics software creates graphs and charts from numeric data – Spot trends and compare data more easily • Visual evidence more compelling • Included in spreadsheet programs • Presentation graphics creates “slide show” presentations – Combine high-quality graphics, audio, and video 64 Communications • The ability to hook the computer up to phone line or cable and communicate with another computer • Typically connected over the Internet – Needs a browser to access other locations on the Internet 65 Other Task Software • Personal Information Managers – Keep track of activities – Typically include appointment calendar, address book, and task manager • Office Suite – A group of basic applications that work together • Easy to share data among applications • Similar look and feel among applications – Integrated application • A “stripped down” version of the office suite 66 Business Software • Vertical Market software • Software for Workgroups • Small Business software 67 Vertical Market Software • Written for a particular type of business • Written by companies who have a comprehensive knowledge of that industry – Allows business to easily maintain information on the business, customers, vendors – Encompasses all of the business’s activities 68 Groupware • Lets a group of people share or track information together – Also called collaborative software – Often combines electronic mail, networking, scheduling, and database technology – Data stored in one central location • Often used by organizations with remote employees 69 Software for a Small Business • Small Office/Home Office (SOHO) – Moderately priced software to perform functions aimed at small business – Examples: • • • • • Accounting software Writing and advertising Customer service Keeping contacts Making sales pitches 70 Ethics and Application Software • Piracy: the acquisition and use of illegal copies of software • Counterfeiting: copying large numbers of CD-ROMs or DVD-ROMs and packaging them to look like the real thing • Unauthorized copying of software is stealing 71 Software Piracy • Examples of piracy – Copying software from a lab or from a friend – Buying 2 or 3 copies of software and distributing it to dozens or hundreds of employees – Buying 1 copy of software and installing it on several computers at home 72 Computers and People • Most organizations have some sort of information technology department – Made up of people who are responsible for the organization’s computer resources – Maintain data and provide services to end users 73 Computer People • Data entry operators prepare data for processing • Computer operators monitor systems, keep peripherals running, and make backups • Librarians catalog processed disks and tapes • Programmers design, write, test, implement, and maintain computer programs 74 Computer People • Systems analysts plan and design entire systems – Must have knowledge in programming, as well as knowledge of the business • Network managers implement and maintain organization’s network(s) • Chief Information Officer (CIO) makes key technology decisions – A key member of the organization’s strategic decisionmaking team 75 References • Capron, H. L. (2000). Computers Tools for an Information Age.(6th ed.). New Jersey, USA: Prentice Hall. • Shell. (2009). Retrieved 30 December 2009 from http://en.wikipedia.org/wiki/ Shell_(computing) • Network Operating Systems. (2009). Retrieved 30 December 2009 from http://en.wikipedia.org/wiki/ Network_operating_system • http://www2.raritanval.edu/departments/cis/fulltime/Schwarz/CCP/UnderstandingComputers/PowerPoint%20Pr esentations/UC12_Chapter05.ppt • http://www.k-state.edu/its/security/training/ roundtables/presentations/SIRT_RoundtableNew%20OSes_USB_drives-Sept09.ppt 76