Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

introduction to computer


Published on

introduction to computer

Published in: Education
  • Login to see the comments

  • Be the first to like this

introduction to computer

  1. 1. Where can you find computers? Computers are used all over the world and in all types of environments. They are used in businesses, manufacturing environments, homes, government offices and non-profit organizations. Schools use computers for instruction and for maintaining student records. Hospitals use computers to maintain patient records and to provide medical care. In addition to these types of computers, there are also many customized computers designed for specific purposes. These computers can be integrated into devices such as televisions, cash registers, sound systems, and other electronic devices. They can even be found embedded in appliances such as stoves and refrigerators and used in automobiles, and aircraft. You can find computer everywhere. Explain the area of impart of computer age in our society (a) The Office (b) Manufacturing Industry (c) Health (d) Finance and Commerce (e) Military Institution (f) Education and Training (g) Leisure The Office: The Mechanised Office started in the second half of the 19th Century with the introduction of Typewriter and Telegraph. Within the 1st half of the 20th Century, additional office technologies had been developed. These are: Automatically switched Telephone, Electric Typewriter, Telex, Duplicating machines, Adding Machines, etc. The rise of Electronics during and after the Second World War brought about a gradual replacement of the Mechanical equipment by the smaller, more reliable more versatile equivalent, e.g. Private Branch Telephone Exchange, Electronic Typewriters, Display Terminals, Copiers and Computers. Office Automation helps to keeps management about the state of production, stocks, and personnel etc., as part of management information system (MIS). More interestingly today, is the talk about electronic office. This is where an office will have a central computer connected to by various officers via terminals in their homes and carry out their official assignments. The most important advantage of this system is speed at which jobs are handled with this system and cutting of cost of transportation by staff from their homes to their various offices. Manufacturing industry: Manufacturing Industries are among the first and most well established fields of application of information technology. It has provided tools for production planning, production design and industrial research. The earliest application of information technology to the manufacturing industries was the Jacquard Loom, where the weaving pattern was controlled by sequence of punched cards. Based on principle, the Numerical Control (NC) of Machine tools came to being in 1952 and started to appear commercially in the early 60’s and took another 10 years before the Paper Tape was replaced by programs stored in the memory of the computers. In such Computer Numerical control (CNC) Machine, various aspects of the machine processing happen under a pre-programmed computer control. Other areas where information technology has done very well are Computer integrated manufacturing (CIM),
  2. 2. Computer Aided Manufacturing (CAM), computer Aided Design (CAD). Computer Aided Design was successfully applied to many fields outside the manufacturing unit, such as computer itself, Architectural and Building Industries. Health: Computer-Controlled life support systems can monitor a patient’s condition via a number of sensor devices checking on, for example, pulse rate, body temperature and blood pressure. This frees nurses for other duties. Computer-assisted diagnosis systems make use of artificial intelligence to assist a physician in diagnosing a patient condition. Another interesting development is the use of the computer to assist the plastic surgeon in the repairs of facial injuries or deformities. Finance and commerce: Every money transactions are of importance to information technology. A record usually needs to be made either formally or informally about the amount, the purpose, the parties involved, and the date of transaction etc. previously recorded on paper and processed by hand or by means of slow Electromechanical machine. This device certainly was inadequate hence it failed in face of massive growth in transactions. Information Technology has provided us with very good methods of transacting business, e.g. West Union Money Transfer operate by First Bank of Nigeria Plc. and the use of point of sale terminals (POS). Military application: Computer and Telecommunication technologies have been employed for Military purposes ever since their beginning-calculation of ballistics of artillery shells and transmission and decoding messages are among the best-recorded uses of these technologies. The automated battlefield concept includes Missiles, which find their pre-programmed target with very high accuracy. Education and Training: Information Technology is mostly widely used in broadcasting (Telephone, Radio, etc.). Other areas where IT is applicable are Computer Assisted Training (CAT), Computer Managed Learning (CML), with training material such as TUTORIAL on a screen- based terminal. Computer Managed Learning monitors the responses, and answer to the parts of questions. The computer records progress of the learner. Leisure: One of the common use of computer by many today is for whiling away of time when they are bored with work. There are a lot of games than one can play with computer system. Most desktops come with games preinstalled with the operating system and other games can be bought and installed for leisure hours. One can either play such games with the computer or play alone or play with someone else and having the computer as the umpire. Define Computer A computer is an electronic device that receives input, stores it for a period of time, operating it according to a set of instructions (Known as a PROGRAM) and gives the user with an output.. The computer has four components: Input –Accepts data Processing –Manipulates data Output –Produces results
  3. 3. Storage –Stores results Computer is as intelligent as is the program that runs it. Without a program computer is useless. Computer cannot detect wrong feeding of data. Write short note on the following (1) Hardware, (2) Software, (3) Data, and (4) Users Hardware consists of the mechanical parts that make up the computer as a machine. The hardware consists of physical devices of the computer. The devices are required for input, output, storage and processing of the data. Keyboard, monitor, hard disk drive, floppy disk drive, printer, processor and motherboard are some of the hardware devices. Software is a set of instructions that tells the computer about the tasks to be performed and how these tasks are to be performed. Program is a set of instructions, written in a language understood by the computer, to perform a specific task. A set of programs and documents are collectively called software. The hardware of the computer system cannot perform any task on its own. The hardware needs to be instructed about the task to be performed. Software instructs the computer about the task to be performed. The hardware carries out these tasks. Different software can be loaded on the same hardware to perform different kinds of tasks. Data are isolated values or raw facts, which by themselves have no much significance. For example, the data like 29, January, and 1994 just represent values. The data is provided as input to the computer, which is processed to generate some meaningful information. For example, 29, January and 1994 are processed by the computer to give the date of birth of a person. Users are people who write computer programs or interact with the computer. They are also known as skin-ware, live-ware, human-ware or people-ware. Programmers, data entry operators, system analyst and computer hardware engineers fall into this category. Explain the Input-Process-Output Concept A computer is an electronic device that (1) accepts data, (2) processes data, (3) generates output, and (4) stores data. The concept of generating output information from the input data is also referred to as input-process- output concept. The input-process-output concept of the computer is explained as follows— Input: The computer accepts input data from the user via an input device like keyboard. The input data can be characters, word, text, sound, images, document, etc. Process: The computer processes the input data. For this, it performs some actions on the data by using the instructions or program given by the user of the data. The action could be an arithmetic or logic calculation, editing, modifying a document, etc. During processing, the data, instructions and the output are stored temporarily in the computer’s main memory. Output: The output is the result generated after the processing of data. The output may be in the form of text, sound, image, document, etc. The computer may display the output on a monitor, send output to the printer for printing, play the output, etc. Storage The input data, instructions and output are stored permanently in the secondary storage devices like disk or tape. The stored data can be retrieved later, whenever needed.
  4. 4. Why is computer literacy important? How does this notion relate to the idea of a digital divide? Computers have provided an entirely new medium for literacy (reading and writing). Digital literacy has led to great increases in information that can be conveniently and quickly accessed and facilitates the collaboration and sharing of knowledge. With other forms of digital literacy, we are also seeing an increasing reliance on digital modes of communication. Word processing is now the standard for writing and there has been a global uptake of email and usage of the World Wide Web. In addition sites like Facebook, Twitter, YouTube, all speak to digital literacy leading to greater global participation in literacy. There is now the potential for global access to knowledge and an interest in creating more multilingual and multi-literacy online environments as digital technologies facilitate global and intercultural exchange.. The computer has become a part of global business and the education culture, to this end digital literacy has a direct effect on a country’s economy. ‘…digital literacy is so closely connected to the traditional association of literacy and democratic rights, as well as to more specific notions of e-government.’ (Dobson & Willinsky, 2009) List the four generations in order by the component that characterized that generation. 1. First Generation (1937to 1953): Using Vacuum Tubes 2. Second Generation (1954 to 1962): Using Transistors 3. Third Generation (1963 to 1972): Using Integrated Circuits 4. Fourth Generation (1972 to 1984): Using Microprocessors 5. Fifth Generation (1984-1990): Using Artificial Intelligence 6. Sixth Generation (1990-present): Explosive growth of wide area network and improve OS interface Differentiate between a Digital and Analog computer A digital computer uses distinct values to represent the data internally. All information are represented using the digits 0s and 1s. The computers that we use at our homes and offices are digital computers. Analog computer is another kind of a computer that represents data as variable across a continuous range of values. The earliest computers were analog metre. Analog computers are used for measuring of parameters that vary continuously in real time, such as temperature, pressure and voltage. Analog computers may be more flexible but generally less precise than digital computers. Slide rule is an example of an analog computer Discourse the Characteristics of Computer Speed, accuracy, diligence, storage capability and versatility are some of the key characteristics of a computer. A brief overview of these characteristics are— 1. Speed: The computer can process data very fast, at the rate of millions of instructions per second. Some calculations that would have taken hours and days to complete otherwise, can be completed in a few seconds using the computer. 2. Accuracy: Computer provides a high degree of accuracy.
  5. 5. 3. Diligence: When used for a longer period of time, the computer does not get tired or fatigued. It can perform long and complex calculations with the same speed and accuracy from the start till the end. 4. Storage Capability: Large volumes of data and information can be stored in the computer and also retrieved whenever required. 5. Versatility: Computer is versatile in nature. Computers have several limitations too. Computer can only perform tasks that it has been programmed to do. Computer cannot do any work without instructions from the user. It executes instructions as specified by the user and does not take its own decisions. Explain Classification of computer by type of data processed a. Digital computer These are computers that operate on discrete values. That is, values that occur at a point in time. E.g. 0,1,2,3… The output from digital computers is usually in the form of discrete values. This class of computers is commonly found in the business environments, and they include Desk Calculators, Adding machines, and most of the computers we have around, that is, the personal computers. b. Analog computer An analog computer is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. The output of analog computers is usually represented in the form of smooth curves or graphs from which information can be read c. Hybrid computer Hybrid computers are computers that comprise features of analog computers and digital computers. The digital component normally serves as the controller and provides logical operations, while the analog component normally serves as a solver of differential equations. What is a Hardware? The physical parts of the computer that you can actually touch. E.g. Mouse Microphone Keyboard Scanner Monitor Computer Camera List 10 output and input device you know and explain three each Input Device Keyboard Mouse Game controller (or joy pad) Microphone Webcam Image scanner Fingerprint scanner Barcode reader Laser rangefinder Computed tomography
  6. 6. A keyboard is a human interface device which is represented as a layout of buttons. Each button, or key, can be used to either input a linguistic character to a computer, or to call upon a particular function of the computer. Traditional keyboards use spring based buttons, though newer variations employ virtual keys, or even projected A Mouse is any human interface device that allows a user to input spatial data to a computer. In the case of mice and touch screens, this is usually achieved by detecting movement across a physical surface. Analog devices, such as 3D mice, joysticks, or pointing sticks, function by reporting their angle of deflection. Movements of the pointing device are echoed on the screen by movements of the cursor, creating a simple, intuitive way to navigate a computer's GUI. A webcam is a video camera that feeds or streams its image in real time to or through a computer to computer network. When "captured" by the computer, the video stream may be saved, viewed or sent on to other networks via systems such as the internet, and email as an attachment. When sent to a remote location, the video stream may be saved, viewed or on sent there. Unlike an IP camera (which connects using Ethernet or Wi-Fi), a webcam is generally connected by a USB cable, or similar cable, or built into computer hardware, such as laptops. Output Device Monitor Printers (all types) Plotters Projector LCD Projection Panels Computer Output Microfilm (COM) Speaker(s) Headphones Voice output communication aid Automotive navigation system A monitor or a display is an electronic visual display for computers. The monitor comprises the display device, circuitry and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors used a cathode ray tube (CRT) about as deep as the screen size. In computing, a printer is a peripheral which makes a persistent human readable representation of graphics or text on paper or similar physical media. The two most common printer mechanisms are black and white laser printers used for common documents, and color inkjet printers which can produce high quality photograph quality output. A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer types of projectors can project the image
  7. 7. directly, by using lasers. A virtual retinal display, or retinal projector, is a projector that projects an image directly on the retina instead of using an external projection screen. What is a Software? Software is a computer program that is made up of certain instructions or codes that tell your hardware, or computer, what to do. Software can be used to play games, write school papers, or even sort e-mail. E.g. Adobe Reader PowerPoint Excel Photoshop Mavis Beacon Word Using a tree diagram explain categories of Software What is an Operating System (OS)? The OS is a large program made up of many smaller programs that control how the CPU communicates with other hardware components. It also makes computers easier to operate by people because it puts a face to the computer. In other words, operating systems make computers user friendly. Different computer manufacturers use different operating systems. Apple computers use Macintosh OS, Most PC’s commonly use the OS called Windows (XP, Vista, 7) Operating system is system software that controls and coordinates the use of hardware among the different application software and users. OS intermediates between the user of computer and the computer hardware. The user gives a command and the OS translates the command into a form that the machine can understand and execute. OS has two main objectives—(1) to make the computer system convenient and easy to use, for the user, and—(2) to use the computer hardware in an efficient way, by handling the details of the operations of the hardware. OS hides the working of the hardware from the user and makes it convenient for the user to use the machine. The application program used by the user requires the use of the hardware during processing. Some examples are—display of application’s user interface, loading a program into memory, using I/O devices, allocating CPU to different processes during execution, and store or load data from hard disk. When using the machine, the user gives the command to perform the required actions to the OS and the OS handles all the operational steps. The user is not bothered about how these actions will be performed. This is the job of OS. OS provides an interface to the application programs to interact with the hardware. The user need not get into the details of this interaction. At the other end, the different resources of computer hardware have to be managed and controlled. This includes managing the communication between different devices, controlling the sequence and execution of processes, allocating space on hard disk, providing error handling procedures etc. OS supervises and manages the hardware of the computer. Explain the following relating them to types of Operating system, (1) Single user, (2) Multiuser, (3) Multitasking, (4) Multiprocessing, (5) Real time, and (6) Embedded OS are classified into different types depending on their capability of processing.
  8. 8. Single User and Single Task OS is for use by a single user for a standalone single computer for performing a single task. Operating system for Personal Computers (PC) are single-user OS. For example, if the user is editing a document, then a document cannot be printed on the printer simultaneously. Single user OS are simple operating system designed to manage one task at a time. MS-DOS is an example of single user OS. Multiuser OS is used in computer networks that allow same data and applications to be accessed by multiple users at the same time. The users can also communicate with each other. Linux, UNIX, and Windows 7 are examples of multiuser OS. Multiprocessing OS have two or more processors for a single running process. Processing takes place in parallel and is also called parallel processing. Each processor works on different parts of the same task, or, on two or more different tasks. Since execution takes place in parallel, they are used for high speed execution, and to increase the power of computer. Linux, UNIX and Windows 7 are examples of multiprocessing OS. Real Time OS are designed to respond to an event within a predetermined time. These operating systems are used to control processes. Processing is done within a time constraint. OS monitors the events that affect the execution of process and respond accordingly. They are used to respond to queries in areas like medical imaging system, industrial control systems etc. LynxOS is an example of real time OS. Embedded OS is embedded in a device in the ROM. They are specific to a device and are less resource intensive. They are used in appliances like microwaves, washing machines, traffic control systems etc. Explain features of Windows operating system Windows operating system is GUI (graphical user interface) based Built in support for multiple users on a single PC Plug and play support for hardware User friendly interface Uses device driver software for easier installation of new hardware and software What is a CPU (Microprocessor)? Stands for Central Processing Unit, which is the brain of your computer. It does all the thinking for the computer and process all the information to be turned into files on your computer. The clock speed of the microprocessor in now measured in gigahertz (GHz). The higher the number; the quicker the information processed. Write a short note on RAM (Random-Access Memory)? RAM temporarily stores data that the computer is currently working on. It requires for power to be turned on. It is the determining factor in how fast your applications or software run. The information in RAM goes away once the computer is turned off, so it is important to save any work you want to keep. It is measured in megabytes (MBs). The larger the size, the faster it functions Explain the term ReadOnly Memory (ROM)
  9. 9. This is read only memory which is the permanent type of memory the computer stores for information that does not change. It stores the information even when the computer is shut down. ROM is generally installed by the manufactured of the computer as part of its system. How is computer memory measured? Computer memory is measured in Bytes, which is a unit of storage capable of holding a single character. Kilobyte = about 1000 bytes. Megabyte = about one million bytes. Gigabyte = about one billion bytes. Explain the four basic types of mouse actions/usage Single click: Click once on the left mouse button (e.g. single click on an item on the task bar to start a programme) Double click: Click twice in rapid succession on the left mouse button while holding the mouse steady. In Windows O.S, double clicking is used to launch programs from the desktop. Right click: Click once on the right mouse button. This opens up a menu of functions you can select and immediately perform. Drag and drop: Click and drag. This is achieved by choosing an item, placing the mouse cursor over it and pressing down on the left mouse button. Do not let go. Drag the object to a new location and release the mouse button. Hover: In many applications, holding your mouse over an icon without clicking will bring up a short explanation of the function of the icon. The navigation icons in Netscape Navigator will display more information about themselves when you hold the mouse cursor over them. Write short not on a Motherboard This is the main circuit board that connects all other internal components, such as the CPU and memory. It’s like the blood vessels inside the human body, which connect to all the vital organs. Instead of blood vessels, the motherboard uses tiny electrical paths to connect each part of the computer. One important part on the motherboard is the BIOS, which is where the computer's settings are stored and changed. What is a BIOS? Basic Input/Output System. When the computer is first turned on (booted), the BIOS is responsible for establishing basic communication with all the computer parts. It is the program which wakes the computer up when you turn it on and reminds itself what parts it has and what each part is supposed to do. After booting and performing a few system checks, It turns the computer over to your operating system. Outline and write on 5 different kinds of storage devices  Compact Disc Re-Writable (CD-RW) is a type of disk which enables you to write onto it several times. The storage capacity can vary, but it typically holds 700 MB of data.  Compact Disc Read- Only Memory (CD-ROM) is a disk that enables you to write onto it once. These are typically used to save music or data that does not change.
  10. 10.  Digital Versatile Disc (DVD) is a type of disk that holds digital representations that combine sound and graphic.  A Hard drive is a large capacity, permanent storage used to hold programs and documents. This is stored inside your computer and holds the largest amount of data  A Floppy Disk is a portable magnetic disk that can hold up to 1.44 MB of data. This holds the least amount of data.  A USB or flash disk is a small, portable flash memory card that plugs into a computer’s USB drive and functions as a portable hard drive. What is a Peripherals, give five each of Input Device and Output device that you know. These are devices that connect to your computer, but are separate from it. These devices can be categorized as either Input device, Output device or Auxiliary Storage. Input Device: Mouse, Keyboard, Microphone, Joystick, Light pen, Digital Camera… Output Device: Monitor, Scanner, Printer, Speakers, Computer Aided Manufacturing (CAD) tool Auxiliary Storage Device: Hard disk, Magnetic Tape, Floppy disk, Optical disk, Punched Card and Paper Tape. Write short not on the Power Supply  It supplies the fuel (power), for the computer. Supply power to the motherboard and the drives. It contains a fan that helps assist in the task of cooling the computer. It comes in a variety of wattages. 200 watt and 250 watt, are the most commonly used. Write a note on Computer virus. A computer virus is a malware program that, when executed, replicates by inserting copies of itself (possibly modified) into other computer programs, data files, or the boot sector of the hard drive; when this replication succeeds, the affected areas are then said to be "infected". Viruses often perform some type of harmful activity on infected hosts, such as stealing hard disk space or CPU time, accessing private information, corrupting data, displaying political or humorous messages on the user's screen, spamming their contacts, or logging their keystrokes. However, not all viruses carry a destructive payload or attempt to hide themselves—the defining characteristic of viruses is that they are self-replicating computer programs which install themselves without user consent. When a virus attaches itself to another file it infects it. They are normally inactive until infected program is run. They are broadly classified into three categories. a. Boot infectors b. System infectors c. Executable program infectors Boot infectors: Create bad sectors. They remain in the memory until the system is shutdown. System infectors: It infects the hard disk or: bootable floppies which may contain system files. Executable program infectors: These are dangerous and devastating. They spread to almost any executable program attaching themselves to programming files. Where do I save files?
  11. 11. Decide the folder in which you want to save the file. If you do not want to save the file in the default folder, create a new folder that explicitly describes the subject. Select a name that you can easily remember.. How do I save files? Use the save feature in your software found under the File menu. What should I name the files? Choose a name that most describes your file and that you can easily remember. Windows Operating System allows you to use up to 255 characters to name your file. However, it is advisable that you limit your file name to 8 characters to make it easily accessible to those that do not use Windows Operating System. You can use blank spaces to separate words in the file name. What characters can I not use? /: *? “‘< > and | are forbidden. What about extensions? You can add a three-letter extension. Alternatively, you can let the software do it. Normally, it works well to let the software decide. How do I find the files after saving them? You can find you file using the window explorer from the start button click on my document which is the default folder for saving of files; except when a specific location is use. Write on following services found on the Internet: E-mail, Web, File transfer, Chat, Message board, instant messaging, Ecommerce E-mail: Electronic mail, most commonly referred to as email or e-mail since 1993, email is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Simultaneously; they need connect only briefly, typically to a mail server, for as long as it takes to send or receive messages. Web: The World Wide Web (www, W3) is an information system of interlinked hypertext documents that are accessed via the Internet. It has also commonly become known simply as the Web. Individual document pages on the World Wide Web are called web pages and are accessed with a software application running on the user's computer, commonly called a web browser. Web pages may contain text, images, videos, and other multimedia components, as well as web navigation features consisting of hyperlinks. File transfer Protocol: File transfer protocol has the facilities that can be used for moving files from one computer to another. It is the common language for sharing data. Unlike Telnet, in which you must often know a specific password to successful log onto the remote computer, anonymous FTP has become a common place. With anonymous FTP, anyone on the Internet may transfer files from and sometimes to a remote system using the word anonymous as the user identification.
  12. 12. Chats may refer to: Communication, Conversation, particularly casual. Online chat, text message communication over the Internet in real-time. Synchronous conferencing, a formal term for online chat. SMS chat, a form of text messaging Message board: An Internet forum, or message board, is an online discussion site where people can hold conversations in the form of posted messages.They differ from chat rooms in that messages are often longer than one line of text, and are at least temporarily archived. Also, depending on the access level of a user or the forum set-up, a posted message might need to be approved by a moderator before it becomes visible. Forums have a specific set of jargon associated with them; e.g. a single conversation is called a "thread", or topic. Instant messaging: A real-time Internet communications service that allow two or more end user to communicate instantly. Ecommerce: Electronic commerce, commonly known as E-commerce or eCommerce, is trading in products or services using computer networks, such as the Internet. Electronic commerce draws on technologies such as mobile commerce, electronic funds transfer, supply chain management, Internet marketing, online transaction processing, electronic data interchange (EDI), inventory management systems, and automated data collection systems. Modern electronic commerce typically uses the World Wide Web for at least one part of the transaction's life cycle, although it may also use other technologies such as e-mail. Electronic Commerce is the financial business transaction that occurs over an electronic network such as the Internet. Some of it features are Electronic storefront, shopping cart and online auction Define the term internet Internet is an international network of networks of computers linking different types of users: Academic, Industries, Government, Health Institutions, military, individuals, etc, for the purpose of sharing information. As a communication network among computers, the internet allows you to locate and retrieve information on other computers linked to the internet as well as send messages electronically to and from other people elsewhere on the internet. List the benefits of internet Application (a) Downloading of information (b) Advertisement (c) Accessing newspapers, magazines and academic journals (d) On-line banking (e) Accessing international media (CNN, BBC, VOA) What is the World Wide Web (WWW)? A worldwide collection of electronic documents also called the Web, Each document is called a Web page can contain text, graphics, sound, video, and links to other Web pages: A Web site is a collection of related Web pages How the Internet Works
  13. 13. Request data from the server on Internet. 2: Modem converts digital to analog signals. 3: Data travels through telephone lines to a local ISP. 4: Data passes through routers. 5: Regional ISP uses leased lines to send data to a national ISP. 6: National ISP routes data across them country. 7: National ISP passes data to local ISP. 8: Server sends data back to you What are the possible threats to a computer systemand how to provide security? Threats a. Privacy b. Integrity c. Environmental damage d. Human threats e. Software threats f. Unauthorized access g. Computer viruses Security a. Physical protection of machine and media. b. Giving passwords and users ID c. Using Licensed software d. Use of Cryptography e. Use of Spike busters and UPS 3) Explain the typical causes of computer failures. a. Break down of components: If part of a computer is bad it can affect the whole computer not to come up. E.g. if the RAM is bad the computer will not boot up at all. b. Excessive dust or humidity Excessive humidity can damage and lessen the performance of a computer. It can exaggerate the effects of extreme temperatures on computer components. For example, dry air causes static electricity to build up. Coupled with the increased conductivity from heat, this can cause errant discharges. Conversely, cold and humid areas create condensation and water, which can create a short circuit. c. Virus: A computer virus is a malware program that, when executed, replicates by inserting copies of itself (possibly modified) into other computer programs, data files, or the boot sector of the hard drive; when this replication succeeds, the affected areas are then said to be "infected". d. Voltage fluctuation: A sudden loss of electricity can interrupt important threads and leave your computer in an inoperable state. System files are the largest concern. Consider what happens when a hard drive is writing data to the disk but suddenly shuts down in the middle of it. Suppose the file being written was a system file necessary for the booting process? Now that file is corrupted and you can’t boot up your computer without going through an involved recovery procedure. Furthermore, frequent power outages can reduce a hard drive’s physical lifespan. The read-and write head, which hovers over the spinning platters during operation, snaps back into its
  14. 14. original position upon power loss. This sudden movement can cause tiny imperfections that accumulate over time, increasing the likelihood of a “head crash”: a malfunction that occurs when the head touches and scrapes the platter surfaces, effectively destroying the hard drive. Solid-state drives can also suffer catastrophic damage from sudden power cuts. Issues can range anywhere from data corruption to total malfunction. e. Corrosion: is the gradual destruction of computer component (usually metals) by chemical reaction with their environment, which can damage and lessen the performance of a computer. Explain the different factors affecting the processing speed of CPU. • CPU Speed/Clock speed: Speed of CPU also known as clock speed. The clock speed is the number of instructions executed by the CPU in one second It is measured in megahertz (million instructions per second). The average speed of a new CPU is about 1000MHz to 4000 MHz (1 to 4gigahertz). • Instruction set: The number of instructions decide the efficiency of a CPU. More the instructions, less efficient is the CPU and less the instructions, more efficient is the CPU. • Word size/Registersize: The size of registers determines the amount of data the computer can work with at a time. Normally it is 32 bits. Smaller the size of register, slower will be the computer. . It is also known as Word size. It varies from 16 bits to 128 bits. • Data bus capacity: Width of a data bus determines the largest number of bits that can be transported at one time. • Cache Memory size: Cache memory is a high speed memory. Greater the cache, faster a processor runs. Most modern processors can execute multiple instructions per clock cycle which speeds up a program. Some CPU’s have storage for instructions and data built inside the processor chip. This is called internal cache or L1 cache memory. • Memory Size: The amount of PRIMARY STORAGE (RAM) determines the size of program that can be kept in primary storage, which is faster than secondary storage. There by the speed of computer increases. The size of RAM varies from 64 MB to 4 GB. Explain the General Structure of CPU. Program counter: This register stores address of next instruction to be executed. Memory address register (MAR): This register specifies address in memory where information can be found. This register is also used to point to a memory locations where information can be stored. Memory buffer register: This register acts as an interface between CPU and memory. When CPU issues a Read Memory command, instruction is fetched and placed in MB register. Instruction register-This stores a copy of current instruction. Instruction decoder (ID): ID is an electronic hardware, which decodes instructions. The instructions are further broken down into a set of micro operations, so that they can be executed directly. General purpose registers: They are used to store data. There are 6 GP registers. These are used for storage of data as needed by the program. Arithmetic logic unit: The basic arithmetic operations such as addition, subtraction, multiplication and division are carried out here. These operations need at least two operands, one which is stored in accumulator and the other in the MBR. After the manipulation of data in ALU, the result is transferred to accumulator.
  15. 15. Accumulator: During processing the intermediate data needed for future processing is stored in accumulator. The contents of ACC are used by ALU for operations and later by MBR holds the final result for further action. Define Sorting. Sorting is a method of arranging data items in any order. What is searching? It is a process of locating an element stored in a file. Mention the different structured programming constructs. a. Sequence b. Selection c. Iteration Name the different searching methods. a. Linear Search b. Binary Search Define module. It is an independent set of statements, which can be called in another program. What is the main advantage of linear search method? Ans. It is simple and useful when the elements to be searched are not in any definite order. What is the other name of bubble sort? The bubble sort method is also called as sorting by exchange. What is structured programming? It is a method of using the concept of sequence, selection, iteration and modularity. Name the searching technique which requires sorted elements. Binary Search. What is top-down analysis? Solving a problem by breaking it up into smaller parts is called as top-down analysis. What is top-down approach called as? Top-down analysis is also called as stepwise refinement What is Data? Data is the basic element in any computer processing. Data is a raw (unprocessed) fact or collection of facts and figures or an observation. It may be number, an alphabet, or a sequence of characters. What is Information?
  16. 16. Information is a processed data and has an implicit meaning. Information is a structured data. It is useful for decision making. Write five qualities of information 1. Accurate: Ensures correct input and processing rules 2. Complete: Include all data 3. Trustworthy: Do not hide unpleasant information 4. Timely: Give at the right time 5. Up-to-date: Include all data up to the present time What is a computer network? It can be defined as interconnection of autonomous computers and terminals together using communication systems to facilitate exchange of information. Mention the different types of network. Local area network (LAN), Wide area network (WAN), Metropolitan area network (MAN) What is a file server? It is the main component of the network. It is a very fast computer with a large amount of RAM and storage space. File server stores all the files and application software and operating system. What is a work station? It is also referred to as nodes, clients are the computers connected to the file server. Mention the most widely used interface card. Ethernet cards What are routers? A router translates information from one network to another. Routers select the best path to route a message based on the destination address and origin. What are switches? It is a device that provides a central connection point to cables from server’s workstations and peripherals. What are the functions of the bridges in the network? It provides link between the older network and the new network. Mention different network services. File service, Print and fax services, Message services, Application services, Database services
  17. 17. Mention different data transmission methods. Serial transmission method and parallel transmission method Mention the different communication modes. 1) Simplex 2) half-duplex 3) full-duplex What is topology? It can be defined as physical layout of the cables, arrangement of resources and communication facilities. 15) Mention the different types of topology. Bus, Star, Ring, Tree, Mesh Mention major network architecture. 1) client-server network 2) Peer-to-peer network What is client-server technology? It is a network where one computer acts as the server and another is called client. The server is the most important part of the network system providing access to resources and providing security. Mention the advantage of client-server technology. 1) Resources and security are directly controlled through the server. 2) New technology can be easily implemented in to the system. Mention the disadvantage of client-server technology. 1) Investment on the server and networking cost is high. 2) Network administrator is required. What is peer-to-peer technology? In this architecture all computers are considered equal because all have the same abilities to use the resources available on the network. Here the resources are shared among the nodes. Each computer acts both as client and server. Explain advantages of Computer Network •Speed: The files can be transferred from one Computer to another instantly. •Cost: Application software (Network version) can be installed on one Computer and accessed by other Computers on the Network. This makes maintenance and upgrading of software easy. •Security: The information on the computer can be made available only through password. Further some information can be made available only for reading and not copying. •Resource sharing: Expensive peripheral devices can be shared by many users in a network. •Easy access: Users can access information from any computer that is available on the network. They need go to a specific Computer which may be located in a different building or different location to retrieve information from their account.
  18. 18. Explain different types of Computer networks The different types of Computer networks are • LAN-Local area Network is networking of Computers ia a network in a smaller physical area like a home, office or small group of buildings. The advantage of LAN is high data transfer rate, sharing of resources like printers, files and other applications. The Computers are connected using cables. • MAN-A Metropolitan area Network is a network of computers within a city or metropolitan area. It is an extended LAN. They use fiber optic cables for faster data transmission. A MAN supports both data and voice. Cable televisions are examples for MAN. • Wide area Network-Wide area Networks connect computers in larger geographical areas. The computers are connected using satellite links, undersea cables or long distance telecommunication links. Security of data is high. It supports remote accessing. Internet services are typical example of WAN Explain Network services • File Services-All the data files of an organization are stored in one place and can be shared by many users. Files can be organized and updated systematically. • Print Services- When Printers available on the Network, multiple users can print to the same printer. The network printers are usually faster and more capable. They may have accessories such as envelope readers or multiple paper trays • Database Services-Multiple users can have access to the database at the same time. The Database software ensures integrity of data and provides multiple access. • Message Services-The services include Electronic mail, voice mail, remote access, document transfers across the internet. • Application services- several software applications that are developed using network architecture. The applications can be made available to multiple users. Any up gradation made to these applications is also instantly available to the users.