Computer History

• A computer is a device that can accept input, process this input to produce meaningful output
• Analog computers measure quantities that are continuous and can't be counted, while digital computers handle information that can be counted and perform repetitive arithmetic operations and logical comparisons
• Hybrid computers combine the measuring capabilities of analog computers with the logical and control capabilities of digital computers
• Computer categories based on physical size include microcomputers, minicomputers, mainframe computers, and supercomputers
• Special purpose computers are designed to operate on a restricted class of problems and are dedicated to one function only, while general-purpose computers are programmed to do many different kinds of tasks and can have software installed for many different users
• Capabilities of computers include speed, reliability, accuracy, and memory capability
• Speed in computers allows processing to be accomplished in billionths of a second, and electronic components in modern computers are very reliable and seldom fail
• Errors do not occur in computer-based information systems and can be traced to program logic error or procedural error, and computers can store enormous amounts of data and keep that data readily available for processing
• Computers cannot think alone or independently, are subject to occasional breakdown or malfunction, and have no feelings
• Earliest computing tools include sand tables, abacus, Napier Bones, and slide rules
• Sand tables consist of three grooves in the sand with a maximum of 10 pebbles in each groove
• An abacus consists of sliding beads arranged on a rack, with the upper part containing two beads and the lower part containing five beads per wire
• Napier Bones, invented by John Napier in 1614, enabled fast multiplication, especially for single-digit numbers
• A slide rule is a ruler with a sliding central strip marked with logarithmic scales, used for rapid calculations, especially in science and engineering
• Computer generations are characterized by remarkable improvements from the previous generations, from the abacus to modern computers, continuously evolving and reaching unimaginable heights of innovations in technologies
• The mechanical era of computers includes inventions like Pascaline by Blaise Pascal, Stepped Reckoner by Gottfried Wilhelm von Leibniz, Jacquard Loom by Joseph Marie Jacquard, Difference Engine and Analytical Engine by Charles Babbage, and Hollerith's Tabulating Machine by Herman Hollerith
• Howard Aiken developed MARK-I, capable of performing arithmetic operations and table reference, under the sponsorship of IBM
• First-generation computers in the vacuum tubes era were large, expensive to operate, used vacuum tubes for circuitry, and magnetic drums for memory
• First-generation computers were based on vacuum tube technology, very large, non-portable, slow, expensive to operate, unreliable, and prone to frequent hardware failures
• Examples of first-generation computers include ABC Computer, Colossus, and John Von Neumann machine
• First-generation computers:

  • Examples: ABC Computer, Colossus, John Von Neumann machine, ENIAC, EDVAC, EDSAC, UNIVAC
  • Characteristics: very large, nonportable, slow, expensive to operate, unreliable, prone to hardware failures, required constant maintenance
• Second-generation computers:

  • Transition: transistors replaced vacuum tubes
  • Use of magnetic cores for random memory and magnetic disks for secondary storage
  • Characteristics: smaller, faster, cheaper, energy-efficient, more reliable, typically contained 10,000 transistors
• Third-generation computers:

  • Development: integrated circuits replaced individually wired transistors
  • Use of small-scale integration (SSI) and medium scale integrated (MSI) circuits
  • Introduction of operating systems like UNIX and programming languages like BASIC
• Fourth-generation computers:

  • Characteristic: microprocessor-based systems
  • Development of the Internet, graphical user interfaces (GUIs), mouse, hand-held devices
  • Examples: Altair 8800, Apple II, CRAY-I, Apple Lisa
  • Characteristics: microprocessor circuits containing millions of transistors, reduced size, cost, increased speed, interconnection of computers for better communication and resource sharing
• Fifth-generation computers:

  • Characteristics: use of superconductors, true artificial intelligence, optical disks, voice recognition, imitation of human reasoning, translation of modern language
  • Mega Chips: Fifth-generation computers will use super large-scale integrated (SLSI) chips
  • Parallel Processing: to access several instructions at one time and work on them simultaneously
  • Artificial Intelligence (AI): simulates and reproduces human behavior including thinking, speaking, and reasoning