Introduction to Computers
Introduction to Computers
Computers and other technologies are virtually everywhere in today's society, integrated into almost every aspect of people's lives. Basic computer literacy—knowing about and understanding computers and their uses—is an essential skill today for everyone.
A computer is a programmable, electronic device that accepts data as input, performs operations on that data (processing), presents the results as output, and stores the data or results as needed. These four operations are considered the primary operations of a computer.
Input: Entering data into the computer.
Processing: Performing operations on the data.
Output: Presenting the results.
Storage: Saving data, programs, or output for future use. Most computers today also have communication capabilities. The programs used with a computer determine the tasks the computer is able to perform.
Data is raw, unorganized facts. Information is data that has been processed into a meaningful form. Information is often generated to answer a question. For example, a computer can process employee time card data to produce information about how many employees work less than 20 hours per week. Computers can perform such tasks almost instantly, with accurate results.
Early computing devices were mechanical, not electronic.
Charles Babbage is considered the father of modern digital programmable computers.
The first large-scale, general-purpose computer was ENIAC, developed during World War II. ENIAC could complete in less than two minutes calculations that would take a person 40 hours to do manually.
UNIVAC was the first computer to be mass-produced for general commercial use.
The invention of the microprocessor in 1971 ushered in the fourth generation of computers. This technology allowed the core processing capabilities of a computer to be placed on a single chip.
The physical parts of a computer that you can touch are called hardware. Hardware components can be internal (inside the system unit) or external (connected to the system unit). The instructions or programs used with a computer are called software. Software instructs the computer what to do.
Computers come in various types and sizes, each designed for different purposes.
Embedded Computers: Built into products to give them added functionality, such as in cars and household appliances.
Mobile Devices: Small devices with computing or Internet capabilities, such as mobile phones and tablets. An Internet-enabled mobile phone is called a smartphone.
Personal Computers (PCs): Small computers used by individuals. Desktop computers are designed to fit on or next to a desk. Portable computers, like notebook, laptop, tablet, hybrid notebook-tablet computers, and netbooks, are designed to be carried around easily.
Servers: Used in networks to share resources with multiple users.
Mainframe Computers: Large, powerful computers used by large organizations.
Supercomputers: The fastest, most expensive, and most powerful type of computer.
A computer network is a collection of computers and other devices connected to share resources and communicate with each other. The Internet is the largest and most well-known computer network, linking billions of devices worldwide. The World Wide Web (WWW) is a collection of Web pages available over the Internet. To access a network, a network adapter is needed to connect your device. To connect to the Internet without going through a network, a modem is needed.
Computers and technology have had a significant impact on society, providing many benefits. However, there are also risks associated with a technology-oriented society. These risks include potential security and privacy issues. Computer crime, also known as cybercrime, includes any illegal act involving a computer. It's important to be aware of the benefits and risks of technology and to use it responsibly.
Computers have revolutionized nearly every aspect of modern life, transforming the way we communicate, work, learn, and play. Understanding computers and technology is essential for navigating today’s world. By learning the basics of computer systems, hardware, software, networks, and the societal impact, individuals can feel comfortable using computers and be prepared to use them effectively in their personal and professional lives.
A digital computer is a computer that understands only two (binary) states, usually thought of as off and on and represented by the digits 0 and 1. These 0s and 1s are referred to as bits. All data processed by a computer must be in binary form (0s and 1s). Digital computers use the binary numbering system to represent numbers and to perform math computations. Analog signals represent data with continuous waves, while digital signals represent data by 0s and 1s.
Digital data can only represent a finite number of discrete values, such as 0 and 1, while analog signals are continuous.
Many devices convert information into electrical signals, whether analog or digital, so that it can be transmitted or processed.
Voice and music data in its natural form is analog, while data stored on a computer is digital.
Data to be transmitted over a networking medium must match the type of signal (analog or digital) that the medium supports. If it does not match, it must be converted.
The conversion of data between analog and digital form is performed by networking hardware.
Modulation is the technique of converting a digital signal to its analog form, and demodulation is the reverse process of converting an analog signal to its digital form.
A modem (modulator/demodulator) is used to perform modulation and demodulation.
Transducers convert signals from one form to another. Microphones and speakers are examples of transducers.
Microphones convert sound waves to electrical signals, while loudspeakers convert electrical signals to sound waves. Similarly, video cameras convert light waves to electrical signals, while monitors convert electrical signals to light waves.
A/D (Analog-to-Digital) conversion transforms an analog input into a series of numeric representations. D/A (Digital-to-Analog) conversion is the reverse process, transforming a sequence of discrete numbers back into a continuous analog signal.
Additionally:
Digital communication networks use only digital signals and do not need analog/digital conversion.
Digital systems use digital circuits in their design.
Logic gates and flip-flops are the building blocks of all digital circuits in a computer.
Boolean algebra is used in the design of digital circuits because digital circuits conform to the arithmetic and logic operations of binary numbers.
Digital audio and digital video require that analog signals are converted into a digital form.
Digital signals are a sequence of voltage pulses represented in binary form.
Digital data is represented by 0s and 1s.
Computers possess several key characteristics that contribute to their power and usefulness. These characteristics include:
Automatic Operation: Computers can perform tasks automatically once they are given instructions in the form of a program. They don't require human intervention for each step of the process.
Speed: Computers can perform operations at extremely high speeds. Processing speed is measured in megahertz (MHz) or gigahertz (GHz), indicating the number of instructions a CPU can process per second. The clock speed of a CPU is an important factor in computer performance, though other factors, such as the number of cores, memory, and bus speed also greatly affect processing speed.
Accuracy: Computers can perform calculations and data processing with a high degree of accuracy and precision.
Diligence: Computers can perform repetitive tasks without fatigue or boredom.
Versatility: Computers are capable of performing a wide range of different tasks and can be used for various purposes. They are able to handle numerical, alphabetic, alphanumeric, text, image, voice, and video data.
Memory: Computers can store large amounts of data and instructions. They use different types of memory including RAM (random access memory) for temporary storage during processing, and hard drives, flash drives, and optical discs for long-term storage.
Lack of Intelligence: Computers lack inherent intelligence and cannot make decisions on their own without specific instructions. They do not have the capacity to learn, reason, or solve problems without being programmed to do so.
Lack of Feelings: Computers do not possess emotions or feelings. They operate based on logical instructions and do not have subjective experiences.
Data Processing: Computers are primarily designed for data processing, which involves capturing input data, manipulating the data, and managing output results. This process involves the conversion of raw data into useful information.
Programmability: Computers are programmable devices, which means that their function is determined by the software they are running. They use instructions, also called computer programs, to carry out specific tasks.
Input, Processing, Output, Storage: Computers perform the four primary operations: inputting data, processing data, outputting results, and storing data for future use.
Digital Nature: Computers work in a two-state, or binary, fashion, using 0s and 1s to represent all data. They rely on digital signals for data processing.
Hardware and Software Components: A computer system consists of both hardware (physical components) and software (programs and instructions). The hardware components include the CPU (Central Processing Unit), memory, input devices, output devices, and storage devices.
The history of computers is often described in terms of generations, with each new generation characterized by a major technological development. The basic ideas of computing and calculating go back thousands of years, but the computer as it is known today is a fairly recent invention.
Early Calculating Devices (pre-1946):
Ancient civilizations used tools like notched bones, knotted twine, and hieroglyphics for counting.
The abacus is considered the earliest recorded calculating device.
Other early devices include the slide rule, the mechanical calculator, and Herman Hollerith's Punch Card Tabulating Machine and Sorter.
Hollerith's machine was the first electromechanical machine to read punch cards and was used to process the 1890 U.S. Census data. His company later became International Business Machines (IBM).
Charles Babbage is considered the father of modern digital programmable computers. In 1822 he designed the "Difference Engine" and in 1842 he introduced the idea of the "Analytical Engine" which could perform basic arithmetic functions.
First-Generation Computers (approximately 1946–1957):
These computers were enormous, often taking up entire rooms.
They were powered by thousands of vacuum tubes, which required a great deal of electricity and generated a lot of heat.
First-generation computers could solve only one problem at a time because they needed to be physically rewired to be reprogrammed.
Input was typically through paper punch cards and paper tape, and output was printed on paper.
Significant examples include ENIAC, the world's first large-scale, general-purpose computer, and UNIVAC, the first computer to be mass-produced for general commercial use.
They used machine and assembly languages for programming.
Second-Generation Computers (approximately 1958–1963):
The transistor replaced the vacuum tube, making computers smaller, less expensive, more powerful, more energy-efficient, and more reliable.
Programs and data were input using punch cards and magnetic tape, and output was on punch cards and paper print-outs.
Magnetic tape was used for storage. Hard drives and programming languages such as FORTRAN and COBOL were developed.
The second generation of computers were transistor-based and could perform 200,000–250,000 calculations per second.
Third-Generation Computers (approximately 1964–1970):
Integrated circuits (ICs) replaced transistors, allowing for even smaller and more reliable computers.
Keyboards and monitors were introduced for input and output; hard drives were typically used for storage.
Timesharing operating systems were introduced, allowing multiple users to access a computer's resources simultaneously.
Software started to be unbundled from hardware, leading to an independent software industry.
Jack Kilby invented the integrated circuit in 1958. Integrated circuits incorporated many transistors and electronic circuits on a single tiny silicon chip.
These computers had a memory of a few megabytes, and hard drives had a capacity of a few tens of megabytes.
Fourth-Generation Computers (approximately 1971–present):
The microprocessor was invented in 1971, placing the core processing capabilities of an entire computer on a single chip.
The original IBM PC and Apple Macintosh computers fall into this category.
Fourth-generation computers typically use a keyboard and mouse for input, a monitor and printer for output, and hard drives, flash memory media, and optical discs for storage.
This generation saw the development of computer networks, wireless technologies, and the Internet.
By 1978, the Apple II and the TRS-80 were dominant personal computers.
IBM released its own PC in 1981, and several other manufacturers used IBM's specifications to design their own PCs.
Fifth-Generation Computers (emerging):
Fifth-generation computers are based on artificial intelligence and are capable of natural language input.
Some aspects of fifth generation computers such as artificial intelligence already exist.
Developments include multiprogramming, multi-core processors, parallel processing and cloud computing.
The evolution of computers has led to smaller, more powerful, and more accessible devices. The shift from massive computers to small devices like smartphones has integrated technology into daily life.
Computers can be classified in several ways, including by size, processing power, cost, and intended use. A traditional classification scheme based on size, processing speed, and cost included microcomputers, minicomputers, mainframes, and supercomputers. However, this classification is becoming less relevant due to rapid technological advancements. A more current classification is based on how the computer is used.
Here are the primary classifications of computers based on usage:
Embedded computers are tiny computers built into products to perform specific tasks. They are found in various devices, such as cars and household appliances.
Mobile devices include smartphones, tablets, and other small personal devices with built-in computing and internet capabilities. These devices are typically powered by rechargeable batteries and have wireless connectivity.
Personal computers (PCs) are fully functional computers designed for use by a single individual at a time. They are available in various forms such as desktop computers, notebook computers, and tablet computers.
Desktop computers are designed to fit on or next to a desk and can come in different types of cases, such as tower cases, regular desktop cases, and all-in-one cases. Desktop computers usually conform to either PC-compatible or Mac standards. PC-compatible computers typically run Microsoft Windows, while Mac computers use the OS X operating system.
Portable computers include notebook computers (also called laptop computers), tablet computers, hybrid notebook-tablet computers, and netbooks. They are designed to be carried around easily.
Servers are computers that host data and programs available to a small group of users. They can be used to create virtual environments, which act as separate servers, or deliver each user's desktop to their device.
Mainframe computers are powerful computers used to host large amounts of data and programs accessible to many users. These computers are typically used by large businesses and organizations for day-to-day operations.
Supercomputers are the most powerful computers, designed for complex computations and processing, and they typically run one application at a time. They are used for scientific research and to control critical government systems.
It's important to note that the distinction between some of these categories can be blurred, with some high-end personal computers being as powerful as servers and some personal computers being the size of a smartphone or smaller.
In addition to these categories, computers can be further classified by their function and capabilities:
Workstations are powerful desktop computers used for specialized applications, such as computer-aided design (CAD). They are designed to meet the computing needs of engineers, architects, and other professionals who require greater processing power, larger storage, and better graphics display facilities than standard PCs.
Network computers (NCs) are low-cost microcomputers designed for use with the internet and corporate intranets. They depend on network servers for their operating system, web browser, application software, and data access and storage.
Thin clients are designed solely to access a network.
Internet appliances are ordinary devices that can be used to access the internet.
Computers can also be classified by the type of operating system they use. Common operating systems include Windows, Mac OS, and Linux.
Computers represent both data and program instructions using binary-based coding systems. Because digital computers can only understand two states, usually represented by 0 and 1, all data processed by a computer must be in this binary form. This is referred to as digital data representation.
Here's a breakdown of how different types of data and programs are represented:
Bits and Bytes:
The smallest unit of data that a computer can recognize is a bit, which represents either a 0 or a 1.
A byte is a group of bits that the computer operates on as a single unit, typically consisting of eight bits. A byte is generally used to represent one character of data.
Numerical Data:
The binary numbering system, which uses only the digits 0 and 1, is used to represent numbers and perform math computations.
Text-Based Data:
Coding systems like ASCII (American Standard Code for Information Interchange) and Unicode are used to represent text-based data, including alphanumeric characters and special symbols.
Multimedia Data:
Graphics data, such as images, are stored as bitmap images, which are made up of a grid of small dots called pixels. The color of each pixel is represented by bits. The more bits used, the better the image quality.
Audio and video data are also represented in binary form to be used with a computer.
Software Programs:
Software programs are represented in machine language, which is a binary code consisting of 0s and 1s.
Before a computer can execute an instruction, it must convert it into machine language.
While early computers required programs to be written directly in machine language, modern computers allow programs to be written in programming languages which are then translated into machine language.
Coding Systems:
Coding systems translate data back and forth from symbols that devices can manipulate to symbols that people use.
The specific coding system used depends on the type of data being represented.
ASCII is a fixed-length, binary coding system used to represent text-based data for computer processing on many types of computers.
Unicode is an international coding system for text-based data using any written language.
Digital Data Representation:
Converting data to 0s and 1s is called digital data representation.
This process is essential for computers to understand and process data.
The 0s and 1s can be represented in various physical ways, such as with an open or closed circuit, the presence or absence of electronic current, or different magnetic alignments.
Machine Language:
Machine language is a binary-based programming language that a computer can execute directly.
An instruction in machine language might look like a string of 0s and 1s, but it represents specific operations and storage locations.
Programs must be translated into machine language before the computer can execute them.
Additional Points
The binary system can be used to represent text, graphics, audio and video data.
A computer's memory stores data and instructions in binary form.
Computer professionals often use the octal and hexadecimal number systems as a shortcut for binary, because binary can be difficult to work with.
This system of representing data in binary form is fundamental to how computers function, allowing them to process a wide variety of data and execute complex programs.
Computers are utilized in a wide array of applications across various sectors, transforming how individuals and businesses operate. Here's an overview of the diverse applications of computers:
General Applications
Data Processing: Computers are essentially data processors, capable of storing, manipulating, and retrieving data. This process involves capturing input data, manipulating it, and managing output results, converting raw data into useful information.
Information Processing: Information processing, which is the conversion of data into information, is vital for computer users, businesses, and other organizations. Computers can perform tasks, like sorting through time cards to make a list of employees working a certain number of hours, almost instantly with accurate results.
Productivity: Computers are used to perform tasks efficiently and accurately in a variety of settings.
Decision Making: Computers can provide information to assist employees with decision making.
Home and Personal Use
Home Computing: Computers, smartphones, and the Internet are now mainstream in homes, supporting a range of online consumer activities. Individuals use computers at home to look up information, exchange e-mail, shop, watch TV and videos, download music and movies, research products, pay bills, manage bank accounts, check news and weather, store and organize digital photos, play games, and make vacation plans.
Work-Related Tasks: Many individuals use computers at home for work-related tasks, such as reviewing documents or checking work e-mail.
Communications: Computers allow people to stay in touch with others.
Consumer Kiosks and POS systems: Computers are frequently encountered on the go, such as in consumer kiosks and point-of-sale (POS) systems.
Business and Professional Use
On-the-Job: Computers are used by all types of employees in all types of businesses as a universal tool for decision making, productivity, and communications. This includes corporate executives, retail store clerks, traveling sales professionals, artists and musicians, engineers, police officers, insurance adjusters, delivery workers, doctors and nurses, auto mechanics and repair personnel, and professional athletes.
Access Control: Computers are used for access control at many businesses and organizations, such as authentication systems that allow only authorized individuals to enter an office building or access a company network.
New Job Creation: Many new jobs have been created because of computers, such as jobs in electronics manufacturing, online retailing, Internet applications, and technology-related computer support.
Military Applications: Computers are used extensively by military personnel for communications and navigational purposes, as well as to control missiles and other weapons, identify terrorists, and perform other national security tasks.
Training and Certification: To update their computer skills, many employees take computer training classes or enroll in computer certification programs.
Accounting and Financial Management: Computers are used to create and keep track of customer invoices, manage accounts receivable and accounts payable activities, process payments, and produce financial statements.
Manufacturing: Computers are used to automate manufacturing functions and production processes. They also support the planning of production, obtaining components, scheduling operations, and controlling production.
Sales and Marketing: Computers are used for sales force automation, targeted marketing, and other sales-related activities.
Human Resources: Computers are used in human resource systems to support staffing, training and development, and compensation administration.
Customer Service: Computers are used in call center software and customer relationship management systems.
Enterprise Resource Planning (ERP): Computers are used in ERP systems, which integrate information systems across various functional areas of a business, such as finance and marketing.
Project Management: Software is used to manage resources so that tasks are completed as quickly and efficiently as possible.
Education
Distance Learning: Students can take classes from home or wherever they happen to be using distance learning technologies.
Classroom and Lab Access: Computers and Internet access are often available in the classroom and/or a computer lab for student use.
Campus Wireless Hotspots: Students can often access the Internet from anywhere on campus via a campus hotspot.
Specific Applications
Design and Engineering: Computers are used in computer-aided design (CAD) and computer-aided manufacturing (CAM) to automate design and manufacturing functions.
Scientific Research: Supercomputers are used for scientific research and to control critical government systems.
Multimedia: Computers are used for multimedia applications in various sectors including education, entertainment, corporate, and science and engineering.
Communication and Networking: Computers are used to share internet connections, applications, and other resources. They are also used to facilitate Voice over IP (VoIP), e-mail, video conferencing, messaging, and other communications applications, and for working collaboratively.
Artificial Intelligence (AI): AI applications include cognitive science, robotics, and natural interfaces. AI is applied to many applications in business operations and managerial decision making.
Cybersecurity: Computers are used for network security, including hardware and software firewalls, data and message security, and encryption and decryption.
Social Media and Digital Marketing: Computers are used for social media and digital marketing.
Internet of Things (IoT): Computers are also used in the Internet of Things.
Software Applications
General-purpose applications such as word processing, spreadsheet, database management, and graphics programs are used for home, education, business, and scientific purposes.
Application-specific software is designed to serve a specific purpose or carry out a clearly defined information processing task.
System software allows the computer to operate and runs application software, and includes the operating system.
Utility programs support the operation and management of a computer system.
This wide range of applications highlights the pervasive impact of computers on modern life, making them essential tools in almost every aspect of society.