Chapter 1 Introduction to Computers A Brief History of Computers First Generation computers 1939-1959 Use vacuum tubes and wire circuits 1939 ABC computer completed, clock speed of 60 Hz, uses punch cards for secondary memory 1946 ENIAC 18,000 valves, used 25 KW of power, 100,000 calculations/second Early Vacuum Tube ABC Atanasoff-Berry Computer ENIAC
ENIAC Transistors 1947 Bell laboratories invent the transistor Smaller, cheaper, more reliable, less heat First Transistor Second Generation Computers 1959-1964 Based on transistors and printed circuits Much smaller and less power consumption Integrated Circuit 1958 Invented by Jack Kilby at Texas Instruments Integrates the functions of many transistors into one physical component First Integrated Circuit
Third Generation Computers 1964-1972 Based on integrated circuits, smaller than 2nd Generation Microprocessors 1971 Intel released first microprocessor, the 4004 Equivalent to 2,300 transistors, 4 bit data path, ran at 108 KHz Microprocessors are complex integrated circuits, capable of many different functions Intel 4004 Processor Intel 8088 circuitry Fourth Generation Computers 1972 - Based on microprocessors Utilize LSI (Large Scale Integration), and VLSI (Very Large Scale Integration) Smaller, faster, and more complex than 3rd Generation Outline: What s a computer and what does it do? Computer system Data,information and programs Computer storage Hardware and software Computer networks
Computers in Your Life Most skill-based jobs heavily depend on the creation, collection, and dissemination of information. Computers are also found in the home, as well as in our society in general. Having experience with, and a basic level of comfort with, computers is important for everyone. Computers in Your Life Computers in the Workplace Computers in the workplace are used: as multipurpose workstations as presentation tools in networking as design tools What Is a Computer and What Does It Do? A computer is a programmable electronic device that accepts input, performs processing on that input, outputs the results, and can store the program, data, or output as needed. Input what is supplied to a computer to process Processing the conversion of input to output Output the results of computer processing Storage saving data, results, or programs for future use
What is an input device? Computer system used to enter data and instructions What is an output device? that conveys information to one or more people What is the system unit? Case that contains the electronic components of the computer that are used to process data The Components of a Computer Processor Also called a Central Processing Unit (CPU) The electronic component that interprets and carries out the basic instructions that operate the computer Data,information and programs Memory Consists of electronic components that store instructions waiting to be executed and data needed by those instructions
Data, Information & Programs Data are raw, unorganized facts Text Graphics Audio Video Programs are sets of instructions that tell the computer how to process data to produce information. Information are data that have been processed into a meaningful form. Data, Information & Programs What is the information processing cycle? Input Process Output Storage Communication 0 9 $. 5 2 $ 90.52 Computer storage What is storage? Holds data, instructions, and information for future use Storage media Physical material on which data, instructions, and information are stored Storage device Records and retrieves items to and from storage media
What is a compact disc? Flat, round, portable metal disc CD-ROM DVD-ROM What is a USB flash drive? Portable storage device Small and lightweight enough to be transported on a keychain or in a pocket The average USB flash drive can hold about 500 million characters What is a hard disk? Provides greater storage capacity than a USB flash drive Hardware and software Most are housed inside the system unit Hardware Physical devices of computer system Software Programs that run on computers What is application software? Programs designed to make users more productive
What is system software? Programs that control or maintain the operations of the computer and its devices Operating System (OS) is a set of programs that coordinates all activities among computer hardware Utility Programs allow the user to devices perform maintenance-type tasks usually related to managing a computer, its devices or its programs Users, sometimes called end users, are the people who need output from computer systems. Accountants Managers Clerks Programmers are the people who write the programs that produce the output for the users, and to supply this information. Applications programmers Systems programmers Networks and the Internet What is a network? Collection of computers and devices connected together Computer networks Used to share Resources Hardware devices Software programs Data Information Saves time and money p. 11 Computer Networks and the Internet The Internet A computer network ties users together to share hardware, software, and data, as well as to electronically communicate with each other. Computer networks exist in many sizes and types. Many utilize a network server to run the network and host shared programs and data. The Internet is the largest computer network in the world, connecting millions of PCs and thousands of computer networks together. Two of the most common Internet activities are accessing information on the World Wide Web (a huge collection of Web pages) and exchanging e-mail. To access a computer network, you need a modem or some other kind of network adapter to physically connect your computer to the network. You also need a software program to let you connect to and use the facilities of a network.
What is the Internet? Worldwide collection of networks that connects millions of businesses, government agencies, educational institutions, and individuals Accessing Networks Modem or other network adapter Appropriate software program ISP User ID to log on Web browser p. 12 Fig. 1-7 Network Servers Network servers manage resources on a network. Web servers are servers connected to the Internet to store Web pages. Online = when a computer can send or receive data from a computer network. Computer users often hear the terms online and offline with reference to computer networks and in various other contexts. Any computer in a state that allows it to send data to or receive data from a computer network or other device is said to be online to the network or device. If a device isn t online, it s offline. Computer Systems to Fit Every Need Computers are generally classified in one of four categories: small, or microcomputers ; medium-sized, or midrange computers ; large, or mainframe computers ; and superlarge, or supercomputers. An emerging new category is mobile devices, as discussed next. In general, the larger the computer, the greater its processing power. For example, big computers can process data at faster speeds and can perform more complicated types of processing than can small computers. Big computers can also accommodate larger, more powerful support devices. Computer Systems to Fit Every Need Mobile Devices Microcomputers Midrange computers Mainframe computers Supercomputers
Mobile Devices Very small computing devices Based on a wireless phone or pager Limited Internet access Personal Computers A technological breakthrough in the early 1970s made it possible to produce an entire CPU on a single silicon chip smaller than a dime. These computers-on-a-chip, or microprocessors, can be mass-produced at a very low cost. Microprocessors also made it possible to build inexpensive computer systems small enough to fit on a desk or your lap. The small computers at the heart of these systems have come to be called microcomputers or personal computers (PCs). Personal Computers Although most microcomputers designed for home or business use are desktop computers, smaller PCs are available. Portable PCs include notebook, tablet, handheld, and pocket computers. Network Computers and Internet appliance Personal Computers, cont d. PCs designed for just network use are referred to as network computers or thin clients. PCs or devices designed just for Internet access are called Internet appliances.
Personal Computers, cont d. Most PC users choose between two major computer platforms when they buy a computer PC compatibles and Macintosh computers: PC compatible a personal computer based on Intel microcomputer or compatible CPUs. Often, people refer to PC-compatible computers as the Windows platform or as IBM-compatible PCs. Midrange Computers Midrange computers (or minicomputers) are generally regarded as medium-sized computers. Most of them fall between microcomputers and mainframes in their processing power. Any of several factors might lead an organization to choose a midrange computer over a PC or mainframe. A small or medium-sized company, for example, may find a microcomputer system just too small or too slow to handle its current volume of work. Mainframes Mainstay of almost all large organizations Specialize in high-volume processing of business transactions Mainframes often operate 24 hours a day, serving dozens of users on terminals during regular business hours and processing big jobs such as payroll Supercomputers Some organizations, such as large scientific research laboratories, have extraordinary demands for processing power. To meet applications needs such as very fast speeds and extreme degrees of accuracy, a few vendors offer very powerful computers, called supercomputers. Many supercomputers today are created by linking together multiple PCs or microprocessor chips. Computers and Society The information age = the importance of information technology. Benefits of a computer-oriented society include the fact that day-to-day operations of many individuals are positively affected by computers. Problems include health and privacy concerns. Key Terms Application software. Programs that enable users to perform specific tasks on a computer. Central processing unit (CPU). The chip located inside the system unit of a computer that performs processing and communicates with peripheral devices. Computer. A programmable, electronic device that accepts data input, performs operations on that data, and presents and stores the results. Computer network. A collection of computers and devices that are connected together to share hardware, software, and data, as well as to electronically communicate with one another. Data. Raw, unorganized facts.
Hardware. Physical equipment in a computer system, such as the computer and its peripheral devices. Information. Data that has been processed into a meaningful form. Input. What is supplied to a computer for processing. Internet. The largest and most widely used computer network in the world, linking millions of computers all over the world. Internet appliance. A specialized network computer designed primarily for Internet access and e-mail exchange. Macintosh. A type of personal computer manufactured by Apple. Mainframe computer. A large computer that performs extensive business transaction processing. Memory. A temporary holding place for the computer to store data and program instructions awaiting processing, intermediate results, and processed output. Microcomputer. A computer system based on a microprocessor, designed to be used by one person at a time. Midrange computer. An intermediate-sized and medium-priced computer. Mobile device. A very small device, usually based on a wireless phone or pager, that can perform a limited amount of computing. Network computer (NC). A PC designed to access a network for processing and data storage, instead of performing those tasks locally. Output. The results of computer processing. PC compatible. A personal computer based on Intel microcomputer or compatible CPUs. Personal computer (PC). Another name for microcomputer. Processing. The conversion of input to output. Program. A set of instructions that tells a computer system to perform specific actions. Programmer. A person whose job it is to write, maintain, and test computer programs. Software. Computer programs. Storage. Saving data, results, or programs for future use. Supercomputer. The fastest, most expensive, and most powerful type of computer. Systems software. Programs, such as the operating system, that control the operation of a computer and its devices, as well as enable application programs to run on a computer system. Thin client. Another name for network computer. User. A person who uses a computer system.