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   ICT 1/CS 1N LEC HAND-OUT  Page 1  of 29  INTRODUCTION TO COMPUTERS AY 1 ST  SEM 2013-2014   WEEK 1   INTRODUCTION TO COMPUTERS   COMPUTER DEFINED  A computer is an electronic device, operating under the control of instructions stored in its own memory, that can accept data, process the data according to specified rules, produce results, and store the results for future use. Data and Information Computers process data into information. Data is a collection of unprocessed items, which can include text, numbers, images, audio, and video. Information conveys meaning and is useful to people. Information Processing Cycle Computers process data (input) into information (output). Computers carry out processes using instructions , which are the steps that tell the computer how to perform a particular task. A collection of related instructions organized for a common purpose is referred to as software. A computer often holds data, information and instructions in storage for future use. Some people refer to the series of input, process, output, and storage activities as the information processing cycle . ADVANTAGES and DISADVANTAGES of USING COMPUTERS  Advantages of using Computers:    Speed . When data, instructions, and information flow along electronic circuits in a computer, they travel at incredibly fast speeds.    Reliability. The electronic components in modern computers are dependable and reliable because they rarely break or fail.    Consistency . Given the same input and processes, a computer will produce the same results  –  consistently. A computing phrase  –  known as garbage in, garbage out     –  points out that accuracy of a computer’s output depends on the accuracy of the input.    Storage . A computer can transfer data quickly from storage to memory, process it, and then store it again for future use. Many computers store enormous amounts of data and make this data available for processing anytime it is needed.    Communications . Most computers today can communicate with other computers, often wirelessly. Computers with this capability can share any of the four information processing cycle operations  –  input, process, output, and storage  –  with another computer or a user. Disadvantages of Using Computers:    Health risks . Prolonged or improper computer use can lead to injuries or disorders of the hands, wrists, elbows, eyes, neck, and back. Computer users can protect themselves from these health risks through proper workplace design, good posture while at the computer, and appropriately spaced work breaks. Two behavioral health risks are computer addiction and technology overload. Computer addiction occurs when someone becomes obsessed with using a computer. Individuals suffering from technology overload feel distresses when   ICT 1/CS 1N LEC HAND-OUT  Page 2  of 29  INTRODUCTION TO COMPUTERS AY 1 ST  SEM 2013-2014   deprived of computers and mobile devices. Once recognized, both computer addiction and technology overload are treatable disorders.      Violation of privacy . Nearly every life event is stored in a computer somewhere…in medical records, credit reports, tax records, etc. in many instances, where personal and confidential records where not protected properly, individuals have found their privacy violated and identities stolen.      Public safety . Adults, teens, and children around the world are using computers to share publicly their photos, videos, journals, music, and other personal information. Some of these unsuspecting, innocent computer users have fallen victim to crimes committed by dangerous strangers. Protect yourself and your dependents from these criminals by being cautious in e-mail messages and on Web sites. For example, do not share information that would allow others to identify or locate you and do not disclose identification numbers, passwords, or other personal security details.      Impact on labor force . Although computers have improved productivity in many ways and created an entire industry with hundreds of thousands of new jobs, the skills of millions of employees have been replaced by computers. Thus, it is crucial that workers keep their education up-to-date. A separate impact on the labor force is that some companies are outsourcing jobs to foreign countries instead of keeping their homeland labor force employed.      Impact on environment . Computer manufacturing processes and computer waste are depleting natural resources and polluting the environment. When computers are discarded in landfills, they release toxic materials and potentially dangerous levels of lead, mercury, and flame retardants.  Green computing involves reducing the electricity consumed and environmental waste generated when using a computer. Strategies that support green computing include recycling, regulating manufacturing processes, extending the life of computers, and immediately donating or properly disposing of replaced computers. When you purchase a new computer, some retailers offer to dispose of your old computer properly.  THE COMPONENTS OF A COMPUTER  A computer contains many electric, electronic, and mechanical components known as hardware . These components include input devices, output devices, a system unit, storage devices, and communications devices. Input Devices   An input device is any hardware component that allows you to enter data and instructions into a computer. Five widely used input devices are the keyboard, mouse, microphone, scanner, and Web cam.   Computer keyboard contains keys you press to enter data into the computer. For security purposes, some keyboards include a fingerprint reader, which allows you to work with the computer only if your fingerprint is recognized.   A mouse is a small handheld device. With the mouse, you can control movement of a small symbol on the screen, called the pointer, and you make selections from the screen.   A microphone allows you to speak into the computer. A scanner converts printed material (such as text and pictures) into a form the computer can use.   ICT 1/CS 1N LEC HAND-OUT  Page 3  of 29  INTRODUCTION TO COMPUTERS AY 1 ST  SEM 2013-2014     A Web cam is a digital video camera that allows you to create movies or take pictures and store them on the computer instead of on tape or film. Other input devices are image scanners, barcode reader, touchpad/track pad, sensor, light pen, stylus/puck, touch screen among others. Output Devices  An output device is any hardware component that conveys information to one or more people. Three commonly used output devices are the printer, monitor, and speakers.   A printer produces text and graphics on a physical medium such as paper.   A monitor displays text, graphics, and videos on a screen.   Speakers allow you to hear music, voice and other audio (sounds). System Unit  The system unit is a case that contains the electronic components of the computer that are used to process data. The circuitry of the system unit usually is part of or is connected to a circuit board called the motherboard. Two main components on the motherboard are the processor and memory.   The processor  , also called a CPU (central processing unit) , is the electronic component that interprets and carries out the basic instructions that operate the computer.    Memory consists of electronic components that store instructions waiting to be executed and data needed by those instructions. Although some forms of memory are permanent, most memory keeps data and instructions temporarily, which means its contents are erased when the computers is shut off. Storage Devices Storage holds data, instructions, and information for future use. A computer keeps data, instructions, and information on storage media . Examples of storage media are USB flash drives, hard disks, optical discs, and memory cards. A storage device  records (writes) and/or retrieves (reads) items to and from storage media. Drives and readers/writers, which are types of storage devices, accept a specific kind of storage media.   A USB flash drive is a portable storage device that is small and lightweight enough to be transported on a keychain or in a pocket.   A hard disk provides much greater storage capacity than a USB flash drive. Hard disks are enclosed in an airtight, sealed case. Although some are portable, most are housed inside the system unit. Portable hard disks are either external or removable. An external hard disk is a separate, free-standing unit, whereas you insert and remove a removable hard disk from the computer or a device connected to the computer.   An optical disc is a flat, round, portable metal disc with a plastic coating. CDs, DVDs, and Blu-ray discs are three types of optical discs.   Some mobile devices, such as digital cameras, use memory cards as the storage media. You can use a card reader/writer to transfer the stored items, such as digital photos, from the memory card to a computer or printer.   ICT 1/CS 1N LEC HAND-OUT  Page 4  of 29  INTRODUCTION TO COMPUTERS AY 1 ST  SEM 2013-2014   Communication Devices  A communication device  is a hardware component that enables a computer to send (transmit) and receive data, instructions, and information to and from one or more computers or mobile devices. A widely used communication device is a modem. Communications occur over cables, telephone lines, cellular radio networks, satellites, and other transmission media. Some transmission media, such as satellites and cellular radio networks, are wireless, which means they have no physical lines or wires. WEEK 2 COMPUTER SOFTWARE Software, also called a program, consists of a series of related instructions, organized for a common purpose, that tells the computer what tasks to perform and how to perform them. You interact with a program through its user interface. The user interface controls how you enter data and instructions and how information is displayed on the screen. Software today often has a graphical user interface (GUI). The two categories of software are system software and application software. System software  System software consists of the programs that control or maintain the operations of the computer and its devices. System software serves as the interface between the user, the application software, and the computer’s hardware. Two types of system software are the operating system and utility  programs.   Operating system  –  is a set of programs that coordinates all the activities among computer hardware devices. It provides a means for users to communicate with the computer and other software. Many of today’s computers use Microsoft Windows or Mac OS, Apple’s operating system.   Utility program  –  allows a user to perform maintenance-type tasks usually related to managing a computer, its devices, or its programs. Most operating systems include several utility programs for managing disk drives, printers, and other devices and media. You also can buy utility programs that allow you to perform additional computer management functions. Application software   Application software consists of programs designed to make users more productive and/or assist them with personal tasks. A widely used type of application software related to communications is a Web browser, which allows users with an Internet connection to access and view Web pages or access programs. Other popular application software includes word processing software, spreadsheet software, database software and presentation software. Many other types of application software exist that enable users to perform a variety of tasks. These include personal information management, note taking, project management, accounting, document management, computer-aided design, desktop publishing, paint/image editing, photo editing, audio and video editing, multimedia authoring. Web page authoring, personal finance, legal, tax preparation, home design/landscaping, travel and mapping, education, reference, and entertainment (e.g., games or simulations, etc.).   ICT 1/CS 1N LEC HAND-OUT  Page 5  of 29  INTRODUCTION TO COMPUTERS AY 1 ST  SEM 2013-2014   Software Development  A programmer, sometimes called a computer programmer or developer, is someone who develops software or writes the instructions that direct the computer to process data into information. Programmers use a programming language or program development tool to create computer programs. Popular programming languages include C++, Java, JavaScript, Visual C#, and Visual Basic. CATEGORIES OF COMPUTERS  Industry experts typically classify computers in seven categories personal computers (desktop), mobile computers and mobile devices, game consoles, servers, mainframes, supercomputers, and embedded computers. A computer’s size, speed, processi ng power, and price determine the category it best fits. Due to rapidly changing technology, however, the distinction among categories is not always clear-cut. PERSONAL COMPUTERS  A 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 communication device. Two types of personal computers are desktop computers and notebook computers. 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. The most popular type of mobile computer is the notebook computer. Notebook Computer     –  also called a laptop computer, is a portable, personal computer designed to fit on your lap. Notebook computers are thin and lightweight, yet they can be as powerful as the average desktop computer. Notebook computers usually are more expensive than desktop computers with equal capabilities. Tablet PCs Resembling a letter-sized slate, the Tablet PC is a special type of notebook computer that allows you to write or draw on the screen using a digital pen. With a digital pen , users write or draw by pressing the pen on the screen, and issue instructions to the Tablet PC by tapping on the screen. For users who prefer typing instead of handwriting, some Tablet PC designs have an attached keyboard; others allow you to connect a separated keyboard to the device. Tablet PCs also support voice input so that users can enter text and issue instructions by speaking into the computer. Tablet PCs are useful especially for taking notes in lectures, at meetings, conferences, and other forums where the standard notebook computer is not practical. 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 or on small storage media such as memory cards. You often can connect a mobile device to a personal computer to exchange information between the computer and the mobile device. Some mobile devices are Internet-enabled  , meaning they can connect to the Internet wirelessly. With an Internet-enabled device, users can chat, send e-mail and instant messages, and access the Web. Because of their reduced size, the screens on mobile devices are small, but usually are in color.
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