MIT 11043, PC APPLICATIONS

Transcription

1 MIT 11043, PC APPLICATIONS By: S.Sabraz Nawaz M I S U n i t F a c u l t y o f M a n a g e m e n t a n d C o m m e r c e S o u t h E a s t e r n U n i v e r s i t y o f S r i L a n k a 2013

2 1.1 Introduction to Computer Software A computer needs to be instructed to perform any task. These instructions are given in the form of computer programs, which are written in computer programming languages. A program controls the activity of the processor. A set of programs that are specifically written to provide the user a precise functionality like solving a specific problem is termed as a software package. For example, word processing software package provides functionality to the computer so that it can be used to create text documents like letters and mailing lists. Throughout Software is a generic term for organized collection of computer data and instructions. It is responsible for controlling, integrating, and managing the hardware components of a computer and to accomplish specific tasks. In other words, software tells the computer what to do and how to do it. For example, software instructs the hardware what to display on the user s screen, what kinds of input to take from the user, and what kinds of output to generate. Thus, software communicates with the hardware by organizing the control sequences, and the hardware carries out the instructions defined by the software. 1.2 CATEGORIES OF SOFTWARE Software can be categorised as system software and application software. System software is a generic term for referring to any computer program whose purpose is to help the user to run the computer system, whereas application software employs the capabilities of a computer directly to a task that the user wishes to perform. SYSTEM SOFTWARE System software consists of several programs, which are directly responsible for controlling, integrating, and managing the individual hardware components of a computer system. This software manages and supports the computer system and its information processing activities. System software is more transparent and less noticed by the users, they usually interact with the hardware or the applications. The system software acts as an interface between the hardware of the computer and the software application. System software makes the computer functional. They provide basic functionality like file management, visual display, and keyboard input, and are used by application software to accomplish these functions. Some examples of system software are Operating Systems, Device Drivers, Language Translators, and System Utilities. System software is a program that controls and maintains the operations of the computer and the devices attached to it. System software serves as the interface between the user, the application software and the computer s hardware. The system software must first be installed in your computer before you can install and run application software. OPERATING SYSTEM An operating system is a set of system programs that controls and coordinates the activities of the computer s hardware and application. It is also the platform on which the application software operates. In other words, the operating system instructs the computer s hardware and application system. It also provides the means for users to communicate with the computer and other software. This is the first layer of software loaded into computer memory when it stars up. As the first software layer, all other software that gets loaded after it depends on it for various common core services. These common core services include disk access, memory management, task scheduling, and user interfacing. Popular operating systems include DOS (Disk Operating System), Windows 3.x, Windows 95, Windows NT, Windows 2000, Windows XP, Windows Vista, Mac OS, UNIX BY: S. Sabraz Nawaz Page 31

3 and LINUX. However, DOS and Windows 3.x are currently rarely used as software vendors are continuously coming up with newer versions of the operating system. Functions of an Operating System An operating system performs a number of basic functions that enable you and the application software to interact with the computer. This includes: Managing memory Spooling print jobs Configuring devices Monitoring system performance Administering security and Managing storage media and files User Interface Memory Management The purpose of memory management is to optimize the use of the random access memory (RAM). The OS is responsible for assigning and allocating data and instructions to an area of the memory while they are being processed. The OS is also responsible for monitoring the contents of these items in the memory and to clear them when they are no longer needed by the CPU. For example, the OS manages areas of memory or storage that is known as buffers. A buffer is an area of memory or storage in which data and information is placed while waiting to be transferred to or from an input or output device. Spooling Print Jobs Spooling is a technique used by the operating system to increase efficiency, as the CPU is able to send a print job faster than the printer can print it. A print job is the document, or image that you instruct the application software to print. The OS places print jobs in a buffer instead of sending it to the printer immediately. The information waiting to be printed will be held in the buffer, while the printer will print from the buffer at its own rate. Spooling also allows you to send a second, third, fourth and so on print jobs to the printer while waiting for the first print job to complete. Multiple print jobs are queued in the buffer. Spooling increases efficiency because as soon as a print job is placed in the buffer, the CPU is then ready to process the next instruction. In other words, once the print job is in the buffer, your CPU is ready to proceed with other tasks. Configuring Devices The operating system relies on device drivers to communicate with each device in the computer. A device driver is a small program that accepts commands from another program and converts these commands into commands that the device can understand. Each device (such as the mouse and the keyboard) has its own set of commands. Therefore, each of these devices has their own driver. A device will not function properly unless the correct device driver is installed. Monitoring System Performance Operating systems normally have a performance monitor that assesses and reports information about various system resources and devices. This includes monitoring the CPU, disks, memory, network usage, as well as the number of times a file is read or written. The information in these reports can help you identify problems with resources in order for you to BY: S. Sabraz Nawaz Page 32

4 solve the problems. For example, your computer is running extremely slow and it is determined that the computer s memory is utilized to its maximum. You probably had too many programs running. You should close some of the programs to free memory space or you might consider installing additional memory. Administering Security Most multi-user operating system allows each user to log in with their respective user name or user ID and password. A user name or user ID is a unique combination of characters that identifies one specific user. Meanwhile, a password is a combination of characters that allows you to access certain computer resources. To access a computer that requires a password log on procedure, you will be required to enter your user name and password. The operating system will then compare this with a list of authorized users and passwords. If your entry matches any of the user name and password in the list, you will be granted access to the computer. Some operating systems will also allow you to assign passwords to files so that only authorized users can open them. Managing Storage Media and Files Operating systems contain a program known as a file manager. A file manager performs functions related to storage and file management. Storage and file management functions performed by a file manager includes formatting and copying disks, displaying a list of files on a storage medium, checking the amount of used or free space on a storage medium, as well as copying, renaming, deleting, moving and sorting files. User Interface Operating System provides the interface between the user and the hardware. The user interface is the layer that actually interacts with the computer operator. The interface consists of a set of commands or menus through which a user communicates with a program. Operating System User Interface An interface is a set of commands or menus through which a user communicates with a program. The user interface is the means through which programs control how data and instructions are entered and how information is to be displayed. Types of user interface available are: command-line, menu-driven and graphical user interface (GUI). Often, a combination of interface is used. Command-driven: A command-driven interface is one in which you enter commands. You type keywords or special keys on the keyboard to enter data and instructions. Example: MS DOS. Menu-driven: A menu-driven interface is one in which you select command choices from various menus displayed on the screen. Example: Windows and Mac OS. Graphical (GUI): Allows you to use menus and visual images such as icons and buttons to issue commands. Do not need to key in keywords or special keys to have commands executed. You use the keyboard or mouse to select a menu on the screen or click icons to give instructions. Example: Windows and Mac OS. TYPES OF OPERATING SYSTEM The operating system has evolved immensely from its primitive days to the present digital era. From batch processing systems to the latest embedded systems, the different types of operating system can be classified into six broad categories: BY: S. Sabraz Nawaz Page 33

5 Batch Processing Operating System: This type of operating system was one of the first to evolve. Batch processing operating system allowed only one program to run at a time. These kinds of operating systems can still be found on some mainframe computers running batches of jobs. Batch processing operating system works on a series of programs that are held in a queue. The operating system is responsible for scheduling the jobs according to priority and the resources required. Batch processing operating systems are good at churning through large numbers of repetitive jobs on large computers. For example, this operating system would be best suited for a company wishing to automate their payrolls. A list of employees will be entered, their monthly salaries will be calculated, and corresponding pay slips would be printed. Batch processing is useful for this purpose since these procedures are repeated for every employee each month. Time-Sharing or Multi-User Operating System: This system is used in computer networks that allows different users to access the same data and application programs on the same network. The multi-user operating system builds a user database account, which defines the right that users have on a particular resource of the system. Multi-Tasking Operating System: In this system, more than one process (task) can be executed concurrently. The processor is switched rapidly between the processes. Hence, a user may run more than one process at a time. It is quite common that a user on his computer can have a word processor open and running, an audio CD player playing at the same time. This type of operating system allows a user to switch between the applications and even transfer data between them. For example, it allows a user to copy a picture from an Internet opened in the browser application, and paste it into image editing application. Real-Time Operating System: This system is designed to respond to an event within/a predetermined time. This kind of operating system is primarily used in process control, telecommunications, and so on. The operating system monitors various inputs which affect the execution of processes, changing the computers model of the environment, thus affecting the output, within a guaranteed time period (usually less than 1 second). As the real time operating systems respond quickly, they are often used in applications such as air flight or railway reservation booking. Multi-Processor Operating System: This system can incorporate more than one processor dedicated to running processes. This technique of using more than one processor is often called parallel processing. Embedded Operating System: It refers to the operating system that is self-contained in the device and resident in ROM. Since embedded systems are usually not general purpose systems, these operating systems are lighter or less resource intensive as compared to general purpose OS. Most of these operating systems also offer real-time operating system qualities. Typical systems that use embedded operating systems are household appliances, car management systems, traffic control systems, and energy management systems. BY: S. Sabraz Nawaz Page 34

6 Utility Programs A utility program is a type of system software used to perform maintenance-type tasks such as managing a computer, its devices and its programs. This includes programs that allow users to clean a disk drive or check if there are scratches and errors on a disk. Most utility programs are included in the operating system. Other utility programs can be purchased to perform additional maintenance and management tasks. Examples of utility programs are listed below. System diagnostics Uninstaller Backup utility Disk scanner Data recovery utility File compression utility Disk defragmenter File viewer Antivirus Programs System Diagnostics: Compiles technical information about computer hardware, including peripheral devices to diagnose technical problems. The diagnostic program will make a record of the computer s normal operational settings. When a problem occurs, a report is produced. The problem is diagnosed by comparing any discrepancies between the two reports. Backup Utility: Allows you to copy or backup selected files or your entire hard disk onto another disk or tape. Most backup utilities compress the files during backup so the backup files require less storage space than the original files. You have to restore them using a restore program which is included in the backup utility. The restore program reverses the backup process and restores the files back to their original form. Data Recovery Utility: Used to restore data that has been physically damaged or corrupted. Data can be damaged or corrupted by viruses, bad software, hardware failure or power fluctuations that occur while data or information is being written or recorded. Disk Defragmenter: Reorganizes files and unused space on a computer s hard disk so that data can be accessed more quickly and programs can be run faster. After deletion or saving of many files, there remains many scattered areas of stored files that are too small to be used efficiently. This is known as fragmentation. Fragmentation slows down disk access and thus performance of the entire computer. A disk defragmenter defragments the disk or reorganises it so that the files are repositioned together in one location. Installer/Uninstaller: Adds/removes applications and entries associated with them from the system files. When files are installed, the operating system records the information that it uses to run the software in the system files. The system files of applications will remain in your computer if not uninstalled through an uninstaller. Disk Scanner: BY: S. Sabraz Nawaz Page 35

7 Detects and corrects physical and logical problems on a hard disk/floppy disk. It also searches for and removes unwanted files. Physical problem: one that occurs on the media, such as a scratch on the surface of the disk. Logical problem: one that occurs in the data, such as a corrupted file allocation table (FAT). Windows 98 has two disk scanner utilities ScanDisk and Disk CleanUp. ScanDisk detects and corrects problems while Disk CleanUp searches for and removes unnecessary files, such as temporary files. File Compression Utility: Reduces or compresses the size of files. Compressed files take up less storage space on disk, which improves system performance. Two popular file compression utilities are WINRAR and WinZip. File Viewer: Displays the contents of files. The file viewer normally comes with most operating systems. For example, the file viewer in Windows 98 is known as Windows Explorer. Antivirus Programs: Antivirus program is a utility program that scans the computer to find out viruses and remove them from the system. For example, Norton Antivirus, McAfee, etc. Language Translators: A language translator is a type of system software that translates a program in assembly or higher level language into machine language. Language translators are of thee types: Assemblers: is system software that translates the assembly language program into machine language. Compiler: a language translator that converts the entire program of a higher level language (source code) into machine language (object code), before the compiler executes the program. Interpreter: a language translator that converts each high level language statement into machine language and executes it immediately statement by statement and no object code is saved as with the compiler Application Software Application software is the type of programs that you use once the operating system has been loaded. Examples include word-processing programs (for producing letters, memos etc), spreadsheets (for doing accounts and working with numbers), databases (for organising large amounts of information), games programs and graphics programs (for producing pictures, advertisements, manuals etc). Word processing: A word processing program (such as Microsoft Word) allows you to produce letters, memos, etc., easily. You can easily mail merge a list of names and addresses to produce mass mailers, individually addressed to customers or subscribers. Examples: MS Word 2007, Lotus Word Pro, and Corel WordPerfect Some of the features in word processors and their description Features/Functions Text Editing Description You can change text by deleting, typing over it or insert additional text. BY: S. Sabraz Nawaz Page 36

8 Word Wrap Alignment Headers, Footers & Page Numbering Layout settings Spelling & Grammar Thesaurus Find & Replace AutoCorrect When words extend beyond the right margin, they can and are wrapped around to the next line. Text can be aligned left, centre, right or justified. Headers and footers, with page numbering and other details can be set or reset within the document any time. Documents can be set with margins, tabs, line spacing, indentations, font changes such as bold, underline, font style and size, etc. Looks for misspelled words and problems with capitalization, punctuation, and sentence structure. Provides synonyms, antonyms, and related words for a selected word or phrase. Quickly locates and replaces selected words. Automatically makes corrections for you. Spreadsheet: Spreadsheet software allows you to create table and calculate numbers arranged in rows and columns. It is often used for budgeting, forecasting and other financial tasks. A document produced using a spreadsheet program is known as a workbook that contains many worksheets. It enables you to make 'what if' type projections of how the company will fair in the future and to forecast how changes in prices will affect profits. Example: MS Excel 2007, Corel Quattro Pro and Lotus Some of the features in electronic spreadsheets and their description Function/Feature Formulas Charts What-if analysis Macros Description Spreadsheets allow you to create mathematical formulas which can then be copied and reused. A formula performs calculations on the data in the worksheet and displays the resulting value in a cell that contains the formula. You can readily create graphs in a spreadsheet program by selecting the cells containing the data to be charted and then selecting the type of chart to display. The process of observing the effect of changing one or more cell values. A macro is a sequence of keystrokes and instructions you record and save. By summing up commonly used techniques in a macro, every time that technique is used, it is used in exactly the same way. This increases the reliability of the model that uses it. Databases: A database program (such as Microsoft Access) allows you to compile information and then to search this information to extract just the information you require. For instance, if you have a database of all the equipment housed within an office you can very simply produce a report listing only the equipment above a certain value. Examples: Microsoft Access and Lotus Approach Presentation: Presentation graphics software allows you to create documents called slides that are used in making BY: S. Sabraz Nawaz Page 37

9 presentations. Presentation graphics software is normally used to create visual aids for presentations to communicate ideas, messages or other information to a group of people. Presentation graphics software typically includes clip gallery containing images, pictures, video clips and sound clips to allow for the creation of multimedia presentations. A very useful feature of presentation graphics software is the flexibility to print a presentation in various formats including outline (prints only the text in each slide) and hand-out (prints text and images for distribution to audience). Examples: MS PowerPoint 2007 and Lotus Freelance Project Management: Project management software is normally used when managing projects, to plan, schedule, track, and analyze the events, resources and costs of a project. Project management software helps users track, control and manage project variables, allowing them to complete a project on time and within budget. Example: MS Project Accounts / Payroll: In most large organisations, the accounts are maintained by a computerised system. Due to the repetitive nature of accounts, a computer system is ideally suited to this task and accuracy is guaranteed. Examples: QuickBooks, AccPac, and Sage software Web browsing: Applications used to view and interact with the World Wide Web (WWW). Examples: Microsoft Internet Explorer, Netscape Navigator and Mozilla Firefox Graphics and Multimedia Software: Graphics and multimedia software are software created specifically for a specified field of work, unlike business software, which is used for general-purposes tasks. Graphics and multimedia software are normally used by engineers, architects, desktop publishers and graphic artists. Example: Computer-Aided Design (CAD), Desktop Publishing, Paint/Image Editing, Video and Audio Editing, Multimedia Authoring, and Webpage Authoring Computer-Aided Design (CAD) Software Used by engineers, architects and scientists to create sophisticated designs. Eliminates the need for manual drafting, which is time-consuming. Engineers, architects and scientists are able to make changes to drawings and view the results immediately. Some CAD software comes with 3-D capabilities. Example: AutoCAD 2007 Desktop Publishing Software Used by professional designers to create and produce high-quality colour documents such as textbook, corporate newsletter and product catalogue. Supports page layout allow text and graphics to be arranged on a page-by-page basis. Contain a colour library a standard set of colours used by designers and printers to ensure colours are printed exactly as specified. Example: Adobe InDesign CS3 Paint/Image Editing Software Allows users to draw pictures and shapes, modify existing images, adjust or enhance colours and add special effects. Used by graphic artists, multimedia professionals, technical illustrators and desktop BY: S. Sabraz Nawaz Page 38

10 publishers to create and modify graphic images. Also comes with photo editing capability to allow user to touch-up photographs. Example: Adobe Photoshop CS3. Video and Audio Editing Software Video Editing Software Allows editing and modifying of a segment of a video, known as a clip. You can add special effects, reorder clips, add text or shorten clips. Audio Editing Software Allows modifying of audio clips to produce studio-quality sound tracks. Includes a filter, which is used to enhance sound quality. Multimedia Authoring Software Allows user to create interactive applications by combining the use of text, graphics, audio, video and animations. Normally used to create interactive computer-based presentations, e-learning courseware, product function demonstration, etc. Example: Macromedia Flash and Macromedia Director. Web Page Authoring Software Allows users to create web pages that include text, graphics, video, audio and animations. Allows users to maintain, manage and organize websites. Example: Microsoft FrontPage and Adobe Dreamweaver CS3. Customized software: Kind of application that is specially designed to fulfil a company s particular requirements such as Book Cataloguing System, Hotel Reservation System, Billing System, Leave Management System, etc. These programs are written using programming languages. Popular programming languages include: Java, Visual Basic, Visual C#, C++, COBOL, FORTRAN, DEPHI, etc Software License Categories FREEWARE The term freeware is commonly used for copyrighted software given away free by its author. It is available for free but the author retains the copyright, which means that a user does not have the right to modify anything in the software that is not explicitly allowed by the developer. Thus freeware software permits re-distribution but not modification. Freeware usually carries licence that permits redistribution but may have other restrictions, such as limitations on its commercial use. SHAREWARE Is software that comes with permission for people to redistribute copies for a limited period. Anyone who continues to use a copy is required to pay a license fee. Therefore, a free use of the software is usually limited to a period. It is distributed without payment ahead of time as is common for proprietary software. This software is obtained free of charge by downloading, thus allowing one to try out the program ahead of time. It is accompanied by a request for payment, and often payment is required as per the terms of the license past a set period. FIRMWARE BY: S. Sabraz Nawaz Page 39

11 Is a combination of software, permanently stored in the memory. As the name suggests, firmware is a program or data that has been written onto Read Only Memory (ROM). For example, the BIOS (which is installed inside computer on a chip) checks different parts of the system before loading the operating system into memory. Being firmware, it ensures that it will always be available and will not be damaged in case of a power failure. OPEN SOURCE Is software created by generous programmers and released for public use. The underlying programming code is available to the users so that they may read it, make changes to it, and build new versions of the software incorporating their changes for software. Usually these software are distributed under open-source licence; General Public Licence. Such licence requires that the source code should be distributed along with the software. BY: S. Sabraz Nawaz Page 40