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Chapter 3 COMPUTER SOFTWARE Objectives of this chapter: You can… Identify the types of system software Describe the functions of an operating system Identify the types of operating system Identify utility programs Explain how to work with application software Overview • This chapter covers – System Software • • Operating System Utility Program – Application Software 3.1 Introduction Introduction • Computer software is: – – – A group of programs that connects user with computer devices Comprised of a sequence of instructions Designed to instruct the computer to execute desired functions by the users Introduction (cont’d) Software Layers 3.2 System Software System Software • What is system software? Programs that maintain operation of computer • Two categories Operating Systems Utility Programs Operating System • What is an operating system? – A group of programs that organize and manage the whole computer operations – OS is a set of instructions that coordinate all the internal activities among computer hardware, application programs and users Operating System (cont’d) • OS is controlled by the kernel. • What is a kernel? – Kernel is the supervisor program that manage the memory and devices – Kernel is loaded into the memory from the hard disk (or other storage) during booting until computer is turned off – It is known as memory resident (because it resides in memory as long as the power is on. Non-resident are other programs that resides in hard disk at the same time) Operating System (cont’d) • The functions of an operating system start the computer (Booting) manage programs provide a user interface administer security manage memory control a network provide file management and other utilities monitor performance establish an Internet connection schedule jobs and configure devices Operating System (cont’d) • Booting Process of starting or restarting a computer Cold boot Turning on computer that has been powered off Warm boot Restarting computer that is powered on Operating System (cont’d) • A personal computer boot up process Step 1. Power supply Step 4. Results of POST are sends signal to components in system unit compared with data in CMOS chip Step 2. Processor on a USB drive, in floppy disk drive or CD/DVD drive, and then hard disk Step 6. Kernel (core) of operating system loads into RAM accesses BIOS to start computer Step 3. BIOS runs tests, called the POST, to check components such as mouse, keyboard, and adapter cards Step 5. BIOS looks for system files Step 7. Operating system loads configuration information and displays desktop on screen Operating System (cont’d) • 4 main functions of OS: – Manage computer programs – Manage computer hardware – Provides user interface – Support application software Operating System (cont’d) • Manage computer programs – Managing programs refers to how many users, and how many programs, an operating system can support at one time – An OS can be single tasking, multi-tasking, cooperative multi-tasking, preemptive multitasking, multithreading and multiprocessing – Single tasking • Runs only one program at a time Operating System (cont’d) – Multi-tasking • Same concept as multiprogramming • Allows 2 or more programs at the same time • Divide the programs into active and inactive. Active application is called foreground application and inactive application is background application • CPU does not run the programs simultaneously but manage the resources i.e. memory based on active/inactive applications Operating System (cont’d) – Cooperative Multi-tasking • Based on multi-tasking concept, whereby foreground application controls CPU until program ends • But if program crashes/hang, OS needs to be rebooted – Preemptive Multi-tasking • Based on multi-tasking concept • But if program crashes/hang, OS is able to take over CPU so other programs can be maintained Operating System (cont’d) – Multithreading • One program may execute more than one task • Example print and edit at the same time – Multiprocessing • Use of 2 or more processor at the same time • Programs run simultaneously • Each processor manage own resources • Hardware dependant esp. motherboard Operating System (cont’d) • Manage computer hardware – Memory Unit • OS partitions the memory for each program. • If memory is insufficient, OS may use virtual memory, which allocates a portion of a storage medium to function as additional RAM • In virtual memory, programs/instructions are stored in fixed-sized unit called pages • If memory if full, OS will copy pages into swap file in hard disk and reloaded into memory when needed Operating System (cont’d) With virtual memory (VM), portion of hard disk is allocated to function as RAM Step 1. The operating system transfers the least recently used data and program instructions to disk because RAM is needed for other functions. Step 2. The operating system transfers data and program instructions from hard disk to RAM when they are needed. Operating System (cont’d) – Input/Output Devices • OS provides interrupt handler, a mini program to handle interrupt from input/output devices. • Examples of interrupt are mouse click/scroll/keyboard punch • OS requires device driver to operates hardware devices. Drivers are loaded during booting Operating System (cont’d) • What is a device driver? Program that tells operating system how to communicate with device Also called driver Device Driver With Plug and Play, operating system automatically configures new devices as you install them Operating System (cont’d) • Spooling Sending print jobs to buffer instead of directly to printer Print jobs line up in queue Operating System (cont’d) • Provides User Interface • • • i. OS manages communication between the computers and users Users may login, run application programs, manage files (copy/save) and on/off computers using any type of interface There are 3 types of command instructions: Command line – – Instructions to be typed in i.e. to save a file into diskette is C:\WINDOWS>copy C:myfile.doc a: Users have to memorize instructions Operating System (cont’d) ii. Menu-driven – – User selects instruction from a text-based pull-down menu Instructions are entered either via mouse click/ keyboard <ENTER> of arrow keys iii. Graphical user interface (GUI) – User selects instruction by mouse click or keyboard <ENTER> icons Operating System (cont’d) • User interface Controls how you enter data and instructions and how information displays on screen command-line interface menu-driven interface Operating System (cont’d) • Graphical User Interface (GUI) User interacts with menus and visual images such as icons and buttons Operating System (cont’d) • Some characteristics of operating systems Devicedependent Runs only on specific type of computer Proprietary software Privately owned and limited to specific vendor or computer model Downward compatible Works with application software written for earlier version of operating system Deviceindependent Runs on many manufacturers’ computers Upward compatible Runs on new versions of operating system Operating System (cont’d) • Three categories of operating systems Embedded Network Stand-alone Operating System (cont’d) • Stand-alone operating systems – Example: Windows Windows Version Year Released Windows 3.x 1990 Windows NT 3.1 1993 Windows 95 1995 Windows NT Workstation 4.0 1996 Windows 98 1998 Windows Millennium Edition 2000 Windows 2000 Professional 2000 Windows XP 2001 Windows XP SP2 2004 Windows Vista 2006 Stand-Alone Operating Systems • Windows XP Fast, reliable Windows operating system Available in five editions: Home Edition, Professional Edition, Tablet PC Edition, Media Center Edition, and 64-bit Edition Stand-Alone Operating Systems • Windows Vista Successor to Windows XP, containing a new interface and new / enhanced features Available in several editions, grouped into Home and Business categories Stand-Alone Operating Systems • Mac OS X Available only for computers manufactured by Apple Macintosh operating system has been model for most GUIs Stand-Alone Operating Systems • UNIX Used by power users because of its flexibility and power Most versions offer GUI Available for computers of all sizes Stand-Alone Operating Systems • Linux Popular, free, multitasking UNIX-type operating system Open-source software— code is available to public Both a stand-alone and a network operating system Red Hat provides a version of Linux called Red Hat Enterprise Linux. Operating System (cont’d) • Network operating system Allows users to share printer, Internet access, files, and programs on a network Administers security by establishing user name and password for each user Network Operating Systems • Examples of network operating systems NetWare Designed for client/server networks Windows Server 2003 UNIX / Linux Upgrade to Windows 2000 Server Multi-purpose operating system Solaris Version of UNIX developed by Sun Microsystems Specifically for e-commerce applications Embedded Operating Systems • Embedded operating system Found on most mobile computers, PDAs, and other small devices Windows CE is scaled-down version of Windows Embedded Operating Systems • Operating systems for PDAs Windows Mobile for Pocket PC Palm OS for Palm Embedded Operating Systems • Embedded Linux Scaled-down Linux operating system designed for PDAs, smart phones, smart watches, set-top boxes, Internet telephones, and other devices Embedded Operating Systems • Symbian OS Open-source, multitasking operating system designed for smart phones Make telephone calls, save appointments, browse Web, send and receive e-mail and faxes, and more Utility program • A small program that provides an addition to the capabilities provided by the operating system • Performs maintenance-type tasks, usually related to managing a computer, its devices, or its programs. OS Utility Program • File manager Performs functions such as copying, renaming, deleting, and moving files Image viewer displays contents of graphics file when you double click on it OS Utility Program • Personal firewall Detects and protects a personal computer from unauthorized intrusions The latest update to Windows XP automatically enables the built-in personal firewall upon installation OS Utility Program • Uninstaller Removes a program and In Windows XP, uninstaller is in Add/Remove all associated files Programs in Control Panel OS Utility Program • Disk scanner Detects and corrects problems on hard disk Searches for and removes unnecessary files OS Utility Program • fragmented disk Disk defragmenter Reorganizes files and unused space on hard disk so programs run faster disk after defragmentation process OS Utility Program • Diagnostic utility Compiles technical information about hardware and some software Prepares report outlining problems OS Utility Program • Backup utility Copies selected files or entire hard disk onto another storage medium Most compress files during backup to require less storage space OS Utility Program • Screen saver Causes monitor’s screen to display moving image or blank screen if there is no activity for a specified time To secure computer, user configures screen saver to require password to deactivate Stand-Alone Utility Programs • Antivirus program Identifies and removes viruses in memory, storage media, and incoming files Must be updated frequently Stand-Alone Utility Programs • What is a virus? Potentially damaging computer program Affects computer without user’s knowledge SIGNS OF VIRUS INFECTION • An unusual message or image is displayed on the computer screen • An unusual sound or music plays randomly • The available memory is less than what should be available • A program or file suddenly is missing • An unknown program or file mysteriously appears • The size of a file changes without explanation • A file becomes corrupted • A program or file does not work properly • System properties change Stand-Alone Utility Programs • Spyware Program placed on a computer without the user’s knowledge that secretly collects information about the user Often enters a computer as a result of a user installing a new program A spyware remover is a program that detects and deletes spyware Stand-Alone Utility Programs • Internet filters Programs that remove or block certain items from being displayed Anti-Spam Programs Web Filters Pop-up Blockers Stand-Alone Utility Programs • File compression utility Shrinks size of files to free up room and improve performance Compressed files are sometimes called zipped files Two popular utilities: Winrar and WinZip Stand-Alone Utility Programs • CD/DVD burning software Writes text, graphics, audio, and video files to a recordable or rewriteable CD or DVD Stand-Alone Utility Programs • Personal computer maintenance utility Identifies and fixes operating system problems and disk problems Some continuously monitor computer to identify problems before they occur 3.3 Application Software Introduction • What is application software? Programs designed to make users more productive and/or assist them with personal tasks Introduction (cont’d) Introduction (cont’d) • How is software distributed? – – – – – – – Packaged software, mass-produced Custom software, performs functions specific to a business or industry Open source software, provided for use, modification, and redistribution Shareware, copyrighted software that is distributed free for trial period Freeware, copyrighted software provided at no cost Public-domain software, freeware with no copyright restrictions Pirated Software, software obtained illegally Introduction (cont’d) • Common Features of Software – – • User interface - the user-controllable display screen that allows you to communicate, or interact, with the computer A User can interact with the display screen using a keyboard or a mouse The GUI – – Graphical user interface (GUI) - allows users to use a mouse or keyboard strokes to select icons and commands from menus The three features of GUI are desktop, icons, and menus Introduction (cont’d) – Window A rectangular area of the screen that displays a program, data, and/or information Menu Bar Introduction (cont’d) – Dialog box A window that provides information, presents available options, or requests a response Introduction (cont’d) • The Help Command – Help command - a command generating a table of contents, an index, and a search feature that can help you locate answers Introduction (cont’d) • Software Suite – Individual applications share a common program code – Popular office suites offer a word processor, spreadsheet, database, presentation, and other programs Microsoft Office WordPerfect Office 12 Lotus SmartSuite Word processing Microsoft Word WordPerfect Word Pro Spreadsheet Microsoft Excel Quattro Pro Lotus 1-2-3 Database Microsoft Access Paradox Lotus Approach Presentation Graphics Microsoft PowerPoint Corel Presentations Freelance Graphics Personal information managers Microsoft Outlook Corel Central Lotus Organizer Word Processing • What is word processing software? Allows users to create and manipulate text and graphics This process includes editing, deleting and printing the text and multimedia resources Clip art is a collection of graphics that you can insert in documents Word Processing (cont’d) • Popular word processing features AutoCorrect Columns AutoFormat Grammar Checker Tracking Changes Ink Input Reading Layout Mail Merge Smart Tags Collaboration Tables Macros Research Templates Voice Recognition Thesaurus Web Page Development Spreadsheet software • What is spreadsheet software? – – Organizes data in rows and columns Performs calculations and recalculates when data changes = A1+B2 (*C12) = D1+E2 (*F12) = SUM (C12:Y12) Spreadsheet software (cont’d) • How is spreadsheet organized? Columns identified by letters Rows identified by numbers A cell is the intersection of a column and row Spreadsheet • Function A predefined formula that performs common calculations =B10+B11+B12+B13+B14 =SUM(B10:B14) Spreadsheet software (cont’d) • Charting Allows you to display spreadsheet data in graphical form Spreadsheet software (cont’d) • There are 4 types of charts: i. Column Chart • Used to show changes in time and widely known as the time series ii. Bar Chart • Not suitable for time-based data. Best used for comparison purposes iii. Line Chart • Suitable for time series data iv. Pie Chart • Widely used to show percentages Presentation software • Presentation graphics software Used to create visual aids for presentations A presentation is sometimes called a slide show Example: Microsoft PowerPoint Presentation software (cont’d) – Presentation-graphics programs offer templates to help organize presentations – Templates are of two types: • Design templates - offer formats, layouts, background patterns, and color schemes that can apply to general forms of content material • Content templates - offer formats for specific subjects Presentation software (cont’d) – Graphical presentation program allow users to view the presentation in variety of forms: i. Slide view – ii. View the slides one by one – users may add or edit slide Outline view – Display all text only iii. Slide sorter view – Display graphical images of each slides and allow users to change the position of the slides iv. Notes view – v. Allow speaker notes to be added at each slide Master – All presentation software must have the basic components of the slide 4.5 Database Software Database Software • Database software Allows you to create and manage data Add, change, delete, sort, and retrieve data Database Software (cont’d) – – – Essential to manage a large amount of data, for easy, direct access, to avoid data redundancy and to save time. Examples are: Lotus Notes, Dbase, Microsoft Access and Paradox Database - a collection of interrelated files Database software - a program that sets up and controls the structure of a database and access to the data Database Software (cont’d) • Types of database software: i. Dekstop Database • • • • • ii. For individual use Usage is limited to 5 to 10 users at a time The database functionality is limited as compare to a network databse The data security system is limited especially in locking the database Examples of databases are Microsoft Access, and Microsoft Visual FoxPro Network Database • • • • • • For both individual and corporate use Support bigger number of users that is exceeding 100 users depending on the database brand Moreo funtionalities provided Information access and retrieval is faster Higher security system Examples are Oracle, Microsoft SQL Server, and Dbase Database Software (cont’d) • Benefits of databases: i. ii. iii. iv. v. Avoid data redundancy Data integration Data security Data independence Data maintenance Database Software (cont’d) • The parts of a database A table contains records A record is a row in a table that contains information about a given person, product, object, or event A field is a column in a table that contains a specific category of data within a record Database Software (cont’d) • How a relational database is organized: – Tables of rows and columns – Row (record) - example: a person’s address – Column (field) - example: the person’s last name Database Software (cont’d) • How various records can be linked: – Key field - a field that is used to sort data – Primary key - holds a unique value for each record – Foreign key - used to cross-reference data among relational tables Graphics and Multimedia Software • What is graphics and Multimedia Software? – Software that used to manipulate images, audio and video. Graphics and Multimedia Software • Paint/image editing software Used to create and modify graphical images Sometimes called illustration software Example: Microsoft Paint Corel’s Paint Shop Pro Graphics and Multimedia Software • Professional photo editing software Allows users to customize digital photographs Save images in a variety of file formats Example: Adobe Photoshop, Adobe Ilustrator Graphics and Multimedia Software • Video and audio editing software Video editing software allows you to modify a segment of a video, called a clip Audio editing software allows you to modify audio clips Example: Adobe Premier, Cakewalk Sonar, Cubase etc Graphics and Multimedia Software • Multimedia authoring software Allows you to combine text, graphics, audio, video, and animation in an interactive application Example Macromedia Flash Macromedia Director Other Software (cont’d) • Note taking software Enables users to enter typed text, handwritten comments, drawings, or sketches anywhere on the page Notes are organized like a notebook Other Software (cont’d) • Project management software Allows you to plan, schedule, track, and analyze the events, resources, and costs of a project Other Software (cont’d) • Accounting software Helps companies record and report their financial transactions Other Software (cont’d) Web page authoring software Helps users of all skill levels to create Web pages Some application software programs include Web page authoring programs video audio graphical images animation organize manage maintain Web pages and/or Web sites End of Chapter 3