Computer systems are an integral part of modern life, transforming work, communication, learning, and entertainment. They consist of intricate hardware and software components that collaborate to process information and accomplish various tasks.
The Abacus, invented by the Chinese 4000 years ago, was a wooden frame with metal rods and beads used for simple arithmetic calculations.
John Napier developed Napier's bones, which used 9 strips marked with numerals for multiplication and division, introducing the decimal point system.
Blaise Pascal's 1642 invention, the Pascaline, was the first mechanical calculator, consisting of gears and wheels.
Wilhelm Leibniz improved Pascal's device in 1673, creating the digital mechanical calculator known as the stepped reckoner using grooved wheels.
Charles Babbage's early 1820s invention, the Difference Engine, was a steam-powered calculating machine for basic computations.
Charles Babbage's Analytical Engine in 1830 was a mechanical computer that used punch cards, capable of solving complex mathematical problems and storing data.
Herman Hollerith's 1890 invention, the Tabulating Machine, based on punch cards, computed statistics and recorded data, leading to the creation of IBM in 1924.
In 1930, Vannevar Bush introduced the first electrical computer, the Differential Analyzer, using vacuum tubes for calculations at a rate of 25 per minute.
Howard Aiken's Mark I, a digital computer invented in 1944, could add eight-digit numbers and print results using punched cards; it was 50 feet long and weighed 5 tons.
First-generation computers used vacuum tubes, were slow, expensive, and huge, relied on punched cards, and had limited memory.
Transistors replaced vacuum tubes in second-generation computers, increasing speed, reliability, and reducing size and cost.
Third-generation computers used integrated circuits (ICs) instead of transistors, consuming less power and introducing keyboard and monitor interfaces.
Fourth-generation computers introduced microprocessors, becoming faster, smaller, and supporting advanced input/output devices, modern programming languages, and multimedia software.
Fifth-generation computers aim to understand natural languages and possess thinking capabilities, relying on Artificial Intelligence (AI) and enabling user commands in any language.
A system is a collection of interconnected components working together to achieve specific purposes, found in various aspects of life.
Used to provide data to the computer, including keyboards, mice, microphones, scanners, barcode readers, digital cameras, and touch screens.
The central part of a computer, including the motherboard, microprocessor (CPU), and registers.
Computer memory includes ROM, RAM, and cache memory, each with specific functions and retention properties.
Display text, graphics, and images, including monitors, printers, plotters, and speakers.
Data moves between components through buses, following an instruction cycle that fetches, decodes, executes, and stores data.
Explains how computer hardware and software work together, comprising a CPU, registers, ALU, control unit, and buses.
Memory is measured in bytes, with various units like kilobytes, megabytes, gigabytes, terabytes, petabytes, and exabytes.
Memory can be chip, magnetic, or optical, and memory retention power categorizes it as volatile or non-volatile.
Fast memory used in various devices like RAM, ROM, cache, and SSDs.
Uses magnetized mediums like hard disks and magnetic tapes to store data.
Stores data as pits and lands on optical disks like CDs, DVDs, and Blu-ray disks.
Requires power to retain data, examples include RAM, cache, and registers.
Retains data even without power, including ROM, flash memory, and storage devices like hard disks and optical disks.
Computer software is a collection of programs, data, and instructions enabling computers to perform tasks.
Programming languages instruct computers to perform tasks. Low-level languages (machine and assembly) are hardware-oriented, while high-level languages (e.g., C++, Java) are user-friendly. High-level languages can be procedural, structured, or object-oriented.
Involves exchanging data between devices or systems via networks. Key components include sender, message, medium, protocol, and receiver.
Modes include simplex (one-way), half-duplex (both ways, not simultaneously), and full-duplex (both ways simultaneously). Transmission can be asynchronous (variable timing) or synchronous (fixed timing).
Common devices include hubs, switches, routers, and gateways. Each serves specific roles in network communication.
Includes LANs (local), WANs (wide), MANs (metropolitan), and VPNs (virtual private). Defines the physical layout and connectivity of a network.
Topologies dictate how nodes are connected; options include bus, star, ring, and mesh. Each has unique features and limitations.
Standards (like OSI) establish rules for data transmission, ensuring compatibility and reliability in networks and systems.
The OSI model, developed by ISO, consists of seven layers that perform specific tasks in data communication, including Application, Presentation, Session, Transport, Network, Data Link, and Physical layers.
Various communication protocols, such as TCP/IP, HTTP, FTP, and SMTP, define how data is transmitted and received over networks.
The Internet is a global network of interconnected computer networks that has evolved from ARPANET to the modern era, facilitating communication, information exchange, and connectivity worldwide.
The Internet operates through a decentralized architecture, using packet-switching technology, protocols like TCP/IP, DNS for domain translation, and security measures to transmit and protect data.
The Internet offers global connectivity, vast information resources, real-time communication, e-commerce, education, business opportunities, entertainment, and innovation.
Concerns related to privacy, cybersecurity risks, information overload, digital addiction, the digital divide, online harassment, and health impacts are associated with the Internet.
The Internet is used for communication, information retrieval, e-commerce, social media, entertainment, education, business, research, and innovation.