CC-100-Reviewer.pdf

11-09, 2:05 AM CC-100 Reviewer Introduction to Computing Computers are everywhere: at work, at school, and at home. People use all types and sizes of computers for a variety of reasons and in a range of places. While some computers sit on top of a desk or on the floor, mobile computers and mobile...

11-09, 2:05 AM CC-100 Reviewer Introduction to Computing Computers are everywhere: at work, at school, and at home. People use all types and sizes of computers for a variety of reasons and in a range of places. While some computers sit on top of a desk or on the floor, mobile computers and mobile devices are small enough to carry. Mobile devices, such as many cell phones, often are classified as computers. Generations of Modern Computer First Generation - The peroid of first generation was 1946-1959. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organizations. In this generation, mainly, batch processing operating system were used. Punched cards, paper tape, and magnetic tape were used as input and output devices. Computers in this generation used machine code as programming language. Some computers of this generation were: ‣ ENIAC – Electronic Numerical Integrator And Computer ‣ EDVAC -Electronic Discrete Variable Computer ‣ UNIVAC - Universal Automatic Computer ‣ IBM-701 ‣ IBM-650 Second Generation - The period of second generation was 1959-1965. In this generation, transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes. In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices. In this generation, assembly language and high-level programming languages like FORTRAN and COBOL were used. The computers used batch processing and multiprogramming operating system. Some computers of this generation were: ‣ IBM 1620 ‣ IBM 7094 ‣ CDC 1604 ‣ CDC 3600 ‣ UNIVAC 1108 Third Generation - The period of third generation was 1965-1971. The computers of third generation used integrated circuits (IC's) in place of transistors. A single IC has many transistors, resistors and capacitors along with the associated circuitry. The IC was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient. In this generation, remote processing, time-sharing, multi-programming operating system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation. Some computers of this generation were: ‣ IBM-360 series ‣ Honeywell-6000 series ‣ PDP(Personal Data Processor) ‣ IBM-370/168 ‣ TDC-316 Fourth Generation - The period of fourth generation was 1971-1980. The computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation. Fourth generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to personal computer (PC) revolution. In this generation, time sharing, real time, networks and distributed operating system were used. All the high-level languages like C, C++, DBASE etc. were used in this generation. Some computers of this generation were: ‣ DEC 10 ‣ STAR 1000 ‣ PDP 11 ‣ CRAY-1 (Super Computer) ‣ CRAY-X-MP (Super Computer) Fifth Generation - The period of fifth generation is 1980-till date. In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings. High-level languages like C and C++, Java,.Net etc. are used in this generation. AlI includes: ‣ Robotics ‣ Neural networks ‣ Game Playing ‣ Development of expert systemsto make decisions in real life situations ‣ Natural language understanding and generation. Some computer types of this generation were: ‣ Desktop ‣ Laptop ‣ Notebook ‣ Ultra Book ‣ Chrome Book Digital Revolution The digital revolution is an ongoing process of social, political and economic change brought about by digital technology, such as computer and internet. Technology driving the digital revolution is based on digital electronics and the idea that electrical signals can represents data, such as numbers, words, pictures and music. Without digital electronics, computers would be huge machine. Digitization is the process of converting text, numbers,sound, photos and video into data that can be processed by digital devices. Phases of Digital Revolution Data Processing - is the computing model for the first phase of the digital revolution. The concept of large computers performing tasks based on the input processing-output cycle represents were used from the 1940’s through 1970’s. ‣ EDP (Electronic Data Processing) - is the processing of data by computer or any other machine and its programs in an environment involving electronic communication. Personal Computing - the model for the second phase of the digital revolution, is characterized by small, stand alone computers powered by local software. Local software refers to any software that is installed on a computer hard drive. Network Computing - the third phase of the digital revolution materialized as computers became networked and when the Internet was opened to public used. A computer network is a group of computers linked together to share data and resources. ‣ Internet - is a global computer originally developed as a military project, and was then handed over to the National Science Foundation for Research and academic use. ‣ The Web (short for World Wide Web)- is a collection of linked documents, graphics, and sounds that can be accessed over the Internet. Cloud Computing - it provides access to information, applications, communications and storage over the Internet. Before cloud computing, your computer typically ran software based locally. E-mail, documents, photos, and music all resided on your computer’s hard disk or flash drive. With cloud computing, you can use your browser to access word processing applications that run from the Internet, instead of software that you have installed on your local hard disk. ‣ The expansion of cloud computing is due in part to convergence, a process by which several technologies with distinct functionalities evolve to form a single product. All About Computer What Is a Computer? Computer can be defined as an electronic device that performs rapid computations and generates desired output for users based on input data and programs. Computer can capture, store, retrieve and process data. The data may be numbers, characters, audio, video, images etc. Data and Information Computers process data into information. Data is a collection of unprocessed items, which include text, numbers, images, audio, and video. Information conveys meaning and is useful to people. Characteristics of Computer Computer is a versatile device. It can be designed to do any kind of activity provided all data and instructions are made available to it in digital form. The important characteristics of computer are: 1. Speed - modern computers have incredible speed of processing. Computer speed is measured in units of millisecond (one thousandth of a second), microsecond (one millionth of a second), nanosecond (one billionth of a second), and picoseconds (one trillionth of a second). Advanced computers, including recent microcomputers called super microcomputers, operate in nanoseconds and can carry out millions of instructions per second (MIPS). 2. Accuracy - computer can ensure consistently very high degree of accuracy in computations. It processes data according to the sequence of instructions. Hence, if input data and procedures are correct, the output will be consistently accurate. 3. Huge storage and fast retrieval - computer has huge storage capability. Secondary or auxiliary storage devices are used for permanent storage. 4. Versatility - though computers are basically designed to carry out only arithmetic operations, yet they are capable of performing almost any task that has a series of finite logical steps. 5. Fatigue-free - computer is free from fatigue. It does not get tired of work and never loses concentration. It can perform basic arithmetic operations with the same degree of speed and accuracy for any extent of time continuously, with the same amount of efficiency as the first transaction. 6. Programmable - computer can be programmed to function automatically and this differentiates it from any other calculating device. It functions as programmed for any stretch of time until the condition to terminate is satisfied. 7. Networking Capability - computers can be interconnected into a network. Network in turn can be connected to other networks. Networks extend the capability of computers. Networks provide the basic infrastructure for electronic communications, electronic commerce, and online trading and information services. Categories of Computers Industry experts typically classify computers in six categories: personal computers (desktop), mobile computers and mobile devices, game consoles, mainframes, supercomputers, and embedded computers. A computer’s size,speed, processing power, and price determine the category it best fits. Due to rapidly changing technology, however, the distinction among categories is not always clear-cut. This trend of computers and devices with technologies that overlap, called convergence, leads to computer manufacturers continually releasing newer models that include similar functionality and features. Personal Computer - is a computer that can perform all of its input, processing, output, and storage activities by itself. A personal computer contains a processor, memory, and one or more input, output, and storage devices. Personal computers also often contain a communications device. The term, PC-compatible, refers to any personal computer based on the original IBM personal computer design. ‣ Desktop Computer - is designed so that the system unit, input devices, output devices, and any other devices fit entirely on or under a desk or table. Mobile Computers and Mobile Devices - a mobile computer is a personal computer you can carry from place to place. Similarly, a mobile device is a computing device small enough to hold in your hand. ‣ Notebook Computer - also called a laptop computer, is a portable, personal computer often designed to fit on your lap. Notebook computers are thin and lightweight, yet they can be as powerful as the average desktop computer. A netbook, which is a type of notebook computer, is smaller, lighter, and often not as powerful as a traditional notebook computer. ‣ Tablet PC - or tablet computer, is a special type of notebook computer that you can interact with by touching the screen with your finger or a digital pen. A digital pen looks like a small ink pen but uses pressure instead of ink. Mobile Devices - which are small enough to carry in a pocket, usually do not have disk drives. Instead, these devices store programs and data permanently on special memory inside the system unit or on small storage media such as memory cards. Some mobile devices are Internet-enabled, meaning, they can connect to the Internet wirelessly. ‣ Smart Phone - is an Internet-enabled phone that usually also provides personal information management functions such as a calendar, an appointment book, an address book, a calculator, and a notepad. ‣ PDA (personal digital assistant) - which often looks like a smart phone, PDA differs from a smart phone in that it usually does not provide phone capabilities and may not be Internet enabled, support voice input, have a built-in camera, or function as a portable media player. ‣ E-Book Reader - (short for electronic book reader), or e-reader, is a handheld device that is used primarily for reading e-books. An e-book, or digital book, is an electronic version of a printed book, readable on computers and other digital devices. ‣ Handheld Computer - sometimes referred to as an Ultra-Mobile PC (UMPC), is a computer small enough to fit in one hand. Many handheld computers communicate wirelessly with other devices or computers and also include a digital pen or stylus for input. ‣ Portable Media Player - is a mobile device on which you can store, organize, and play digital media. ‣ Digital Camera - is a device that allows users to take pictures and store the photographed images digitally, instead of on traditional film. Game Console - is a mobile computing device designed for single-player or multiplayer video games. Standard game consoles use a handheld controller(s) as an input device(s); a television screen as an output device; and hard disks, optical discs, and/or memory cards for storage. Mainframe Computer - is a large, expensive, powerful computer that can handle hundreds or thousands of connected users simultaneously. Supercomputer - is the fastest, most powerful computer and the most expensive. The fastest supercomputers are capable of processing more than one quadrillion instructions in a single second. Embedded Computer - is a special-purpose computer that functions as a component in a larger product. Embedded computers are everywhere at home, in your car, and at work. The following list identifies a variety of everyday products that contain embedded computers. ‣ Consumer Electronics: mobile and digital telephones, digital televisions, cameras, video recorders, DVD players and recorders, answering machines. ‣ Home Automation Devices: thermostats, sprinkling systems, security monitoring systems, appliances, lights. ‣ Automobiles: antilock brakes, engine control modules, airbag controller, cruise control. ‣ Process Controllers and Robotics: remote monitoring systems, power monitors, machine controllers, medical devices. ‣ Computer Devices and Office Machines: keyboards, printers, fax and copy machines. The Basic Function of a Computer The computer accepts input - computer input is whatever is entered or fed into a computer system. Input can be supplied by a person (such as by using a keyboard) or by another computer or device (such as a diskette or CD-ROM). The computer performs useful operations - manipulating the data in many ways. This manipulation is called processing. Process is a systematic series of actions a computer uses to manipulate data. The computer stores data - computer must store data so that it is available for processing. Most computers have more than one location for storing data (the hard drive or C:\, and the floppy drive or A:\). The computer produces output - computer output is information that has been produced by a computer. ‣ A computer receives data as input, processes it, stores it and then produces output. Components of Computer All of the components of a computer system can be summarized with the simple equations. Computer System = Hardware + Software + User A computer system is made up of three major components: The physical units of a computer system excluding the third component), constitute its hardware. Hardware consists of mechanical, electrical and electronic parts of the system. Sets of programmed instructions constitute the software. Peopleware is the people element in the system. Computer System Hardware - a computer, like human brain, receives data and instructions, stores them and processes the data according to the instructions given to it. It receives data from input devices, stores them in memory and displays them through an output device. The physical devices that make up a computer are referred to as hardware. Computer hardware can be broadly' classified into two: CPU and peripherals. 1. Central Processing Unit - CPU is the brain of a computer. It has an arithmetic logic unit (ALU) to perform arithmetical and logical operations. It has a control unit to co-ordinate the activities of the CPU and main memory for primary storage. 2. Computer Peripherals - The input/output and storage devices surround the central processing unit (CPU). Hence, they are called the peripheral devices. They are usually the electromechanical devices connected to the CPU that exchange data and programs with the CPU. These peripherals can be further divided into input devices, output devices and secondary storage devices. Input Devices - allow the user to input data and instructions to the computer. 1. Keyboard - is the most popular input device for direct entry of data and instructions into computer. 1875, Christopher Latham Sholes invented the first practical typewriter and the QWERTY keyboard still in use today and he is also known as “The Father of the typewriter” Computer keyboard has three types of keys: Alphanumeric keys - for typing character and numeric data. Punctuation keys - like comma, period, colon, semicolon, question mark etc. Special keys - like function keys, control keys, arrow keys, caps lock etc. ‣ Alt key – Short for Alternate, this key is like a second control key. ‣ Arrow Keys – Most keyboards have four arrow keys that enable you to move the cursor (or insertion point) up, down, right, or left. ‣ Backspace key – Deletes the character just to the left of the cursor (or insertion point) and moves the cursor to that position. ‣ Caps Lock Key – A toggle key that, when activated, causes all alphabetic characters to be uppercase. ‣ Ctrl key – Short for Control, this key is used in conjunction with other keys to produce control characters. The meaning of each control character depends on which program is running. ‣ Delete Key – Sometimes labeled Del, deletes the character at the current cursor position, or the selected object, but does not move the cursor. For graphics-based applications, the Delete key deleted the character to the right of the insertion point. ‣ Enter Key – used to enter commands or to move the cursor to the beginning of the next line. Sometimes labeled Return instead of Enter. ‣ Esc Key – Short for Escape, this key is used to send special codes to devices and to exit (or escape) from programs and tasks. ‣ Function Keys – Special keys labeled F1 to F12. These keys have different meaning depending on which program is running. 2. Mouse - is a small hand-held 'point and click' device that is connected to the CPU through a cable. Douglas Engelbart invented mouse in 1963 at Stanford Research Institute. There are three types of mouse: Mechanical mouse - has a trackball at its bottom. It can be rolled across a flat and smooth surface to control the position of the cursor on the screen. Optomechanical mouse - is more or less the same as the mechanical mouse, but it uses optical sensors to detect motion of the ball. Optical mouse - uses a laser to detect the mouse movement. The mouse requires to be moved along a special mat with a grid so that the optical mechanism has a frame of reference. Optical mouse is more expensive than the other two. Common terms used with mouse directions/actions: ‣ Point - placing the cursor (arrow) on top of a screen object by moving the mouse. ‣ Click - pointing at an object and quickly clicking/pressing the (left) mouse button; then letting go. ‣ Double Click - pointing at an object and (left) clicking twice rapidly. ‣ Drag - pointing at an object pressing and holding down the mouse button; moving the mouse to “drag” the object and releasing the button when the object is in a new place. ‣ Select - pulling down a menu by clicking on the menu name; moving the pointer down to the command you want and then release. ‣ Rollover - move the pointer over an object without clicking. 3. Light Pen - consists of a stylus connected by a cable to the computer terminal. When the stylus is brought into contact with the screen, a dot appears there on the screen. 4. Trackball - was originally built into the keyboard. Running a hand over the trackball made the cursor on the screen to move. 5. Joystick - is a small vertical stick attached to a trackball for easier mechanical movements. It is used mainly in game programs. 6. Scanners - are direct-entry input devices. As the data entry is automatic, the scanners ensure more accurate data entry. 7. Barcode Reader - Barcode is a set of small bars of varying thickness and spacing printed on the packages of products, on the back cover pages of books, tags etc. The barcode reader uses an optical scanner to read product code and converts it into electrical pulses. 8. Voice Recognition Systems - it converts the voice into electrical pulses and then into digital signals for onward transmission to a computer for processing. 9. Digital Cameras - are used to capture images and they can record the images on reusable floppy disks. Images are used with a digitizer for input to the computer. Once the image input is stored in computer, the image can be used in any application. Output Devices -displays result of the computer processing for user. These are the devices that allow information to be represented that is given out to the user, such as a display screen or printer. 1. Visual Display Units (VDUs) - are television-like screens that provide the user-interface in the form of display of text, numbers and images. 2. Speaker and Audio Response Systems - computer can produce verbal output where the output or response can be standardized as replies to special requests for information. 3. Printers - are purely output devices. They produce hard copy output. They can be classified into three broad groups: character printers, line printers and page printers. They can also be classified into impact and non-impact printers based on the basis of the printing mechanism. The impact printing technology uses some mechanical pressure to produce images on paper. Non-impact printers do not use mechanical force to produce output on paper and hence they can produce only single copy output. ‣ Dot Matrix Printer - DMP prints one character at a time as a set of dots produced by the pins on the print head. ‣ Inkjet Jet Printer - is a non-impact printer and is quiet when working. It sprays ink particles through its nozzle. ‣ Laser Printer - is a high-end printer. It uses the same technology as that of Xerox copier machines and it can produce both character and graphic output. ‣ Drum Printer - it is a line printer. It has a drum that rotates at high speed. A set of characters is embossed on the drum. It prints one line of characters at a time. ‣ Magnetic Printer - a drum coated with magnetic material captures the image of the page to be printed. These magnetic spots attract dry ink particles. ‣ Graphic Plotters - Plotters are used for plotting graphs and designs on paper. Architects and designers use plotters to produce blueprints of their designs on paper. Storage Devices 1. Primary Memory (Main Memory) - Memory is used to store the information (programs and data) that the computer is currently using. It is sometimes called main or primary memory. Types of Memory: Random Access Memory (RAM) - This means that any location in memory may be accessed in the same amount of time as any other location. ‣ Static RAM (SRAM) - the word static indicates that the memory retains its contents as long as power is being supplied. ‣ Dynamic RAM (DRAM) - unlike SRAM, must be continually refreshed in order to maintain the data. Read-Only-Memory (ROM) - is used to store programs that are essential for the proper operations of computer system. ROM is non-volatile. 2. Secondary Memory (Storage Devices) - also called auxiliary storage. It has larger storage capacity and is cheaper than primary storage. But access to secondary storage is slower than that to primary storage. Magnetic Disks - are made of rigid metals or synthetic plastic material. The disk platter is coated on both the surfaces with magnetic material and both the surfaces can be used for storage. ‣ Hard Drive - the storage area within the computer itself, where megabytes of space are available to store bits of information. Also known as a hard disk. ‣ Diskette - is a small, removable, flexible mylar plastic disk covered with a thin layer of a magnetic substance, onto which digital data can be recorded and stored. Also known as a floppy disk. Magnetic Tape - is serial access storage medium. It can store large volume of data at low costs. Optical Storage - uses light as the medium for representing data. It uses reflecting surfaces and laser technology to read and write data on a disk. ‣ Compact Disc-Read-Only Memory (CD-ROM) - is a type of optical disk capable of storing large amounts of data. ‣ Compact Disk –Recordable (CD-R) - it can be used to write data on it once. The data on it can be retrieved as and when needed. ‣ Compact Disk Re-writable (CD-RW) - is an optical disk that can be rewritten many times. The data stored on it can be read, erased and re-written as frequently as needed. ‣ Digital Versatile Disk or Digital Video Disk (DVD) - is a large capacity secondary storage device. It stores seven times CD capacity on a single side. Solid State Storage - (sometimes called flash memory) is a technology that stores data in erasable, rewriteable circuitry, rather than on spinning disks or streaming tape. It contains a grid work of circuitry. ‣ Flash Drive (Pen Drive) - secondary storage device based on flash memory, enabling easy transport of data from one computer to another, compact device of the size of a pen. ‣ Memory Card (SD/MMC) - is a flat, solid state storage medium commonly used to transfer files from digital cameras and media player to computers. Processing Unit (PU) ‣ CPU (Central Processing Unit) - is the brain of a computer. It has an arithmetic logic unit (ALU) to perform arithmetical and logical operations. The chip or chips at the heart of a computer that enable it to process data. It is also known as a processor. Chip is a small piece of semi-conducting material (such as silicon) about 1 centimeter (¼ inch) square on which an integrated circuit is embedded. ‣ GPU (Graphics Processing Unit) - is a single-chip processor primarily used to manage and boost the performance of video and graphics. Internal Component ‣ Motherboard - it is the main circuit board of a microcomputer. The motherboard contains the connectors for attaching additional boards. ‣ Complementary Metal-Oxide Semiconductor - CMOS is an on-board, battery powered semiconductor chip inside the computer that stores information. ‣ Expansion Slots - is a socket on the motherboard that is used to insert an expansion card (or circuit board), which provides additional features to a computer such as video, sound, advanced graphics, Ethernet or memory. ‣ Accelerated Graphics Port - AGP is based on PCI, but is designed especially for the throughput demands of 3-D graphics. ‣ Network Card - Network interface card (NIC) is a computer circuit board or card that is installed in a computer so that it can be connected to a network. ‣ Graphic Card - is an expansion card that allows the computer to send graphical information to a video display device such as a monitor, TV, or projector. ‣ Memory Slots - is what allows computer memory (RAM) to be inserted into the computer. ‣ Cooling Fan - is any fan inside, or attached to, a case used for active cooling, and may refer to fans that draw cooler air into the case from the outside, expel warm air from inside. ‣ Power Supply - Power supply unit or PSU, is a component that supplies power to a computer. Most personal computers can be plugged into standard electrical outlets. ‣ Ports - it is a physical docking point using which an external device can be connected to the computer.