itc

• Elements of a computer system include: Hardware, Software, and Peopleware
• Data processing follows the IPO model:

  • Input (Data) is raw facts like texts, numbers, images, and sounds
  • Output (Information) is processed data that is more meaningful to the user
• Hardware is the physical component of a computer system, consisting of tangible physical parts and related devices
• Main units of a computer:

  • Input devices are used to send data to a computer for processing
  • Output devices send data from a computer to another device or user
  • Main storage
  • Processor interprets and carries out basic instructions that operate a computer
• Processor components:

  • Control Unit directs flow of instructions and data within the CPU
  • Arithmetic Logic Unit (ALU) performs arithmetic and logical calculations
  • Registers temporarily hold data and instructions
  • System Clock controls timing of computer operations
• Types of memory:

  • Random Access Memory (RAM) stores data and instructions for processing; volatile
  • Read Only Memory (ROM) contains stored instructions for routine operations; nonvolatile
  • Cache Memory is a high-speed hold area for frequently used information
  • Complementary Metal-Oxide Semiconductor (CMOS) provides information every time the computer is turned on
• Second or Auxiliary Storage Devices:

  • Data is stored permanently
  • Reasons for using auxiliary storage: primary storage limitations and volatility of data in primary storage
  • Types of storage devices: Magnetic Tape, Magnetic Disk, Optical Disc, Solid State Drives
• Peopleware refers to the human role in Information Technology
• IT Group Job Descriptions:

  • Management Computer Group plans and directs computer operations and data processing needs
  • Systems and Procedures Analysts develop computer applications and design tools
  • Computer Engineers test and develop computer components and systems
  • Programming Group writes, tests, and maintains detailed programs
  • Computer Operators set up and ensure proper computer operations
  • Data Encoders prepare and encode documents
  • Librarians catalogue, store, and secure storage media
• Peopleware Specializations:

  • Cyber, System, and Network Security and Forensics
  • Data Analytics and Data Science
  • Data and Database Administrator
  • Software Development
  • Web Design and Application Development
  • Networking, Information, and Communication Technology
• Software consists of instructions or programs that the computer follows
• Two categories of software:

  • System Software
  • Application Software
• System Software controls or maintains the operations of the computer and its devices, serving as the interface between the user, application software, and computer hardware
• Types of System Software:

  • Operating Software
  • Function of OS includes Boot Operation, Monitor Performance, Control Network, Administer Security, Provide File System
• Types of User Interfaces:

  • Command-line Interface
  • Menu-Driven Interface
  • Graphical User Interface (GUI)
• Application Software allows users to perform tasks directly benefiting them, classified into Packaged and Custom software
• Application Software Categories:

  • Business
  • Accounting
  • Graphics and Multimedia
  • Home Personal Educational
  • Communications
• Programming Languages are used to write software, starting from Low Level
• Programming Languages:
• Low Level Languages:

  • Machine Language (1st generation)
  • Assembly Language (2nd generation)
• Procedural Languages (3rd generation)
• Object Oriented Programming Languages
• Software forms:

  • Open-Source Software: provided for use, modification, and redistribution without restrictions from the copyright holder
  • Shareware: copyrighted software distributed at no cost for a trial period
  • Freeware: copyrighted software provided at no cost by an individual or company that retains all rights to the software, distributed to expand the market share of a "premium" product
  • Public-Domain Software: software with no ownership such as copyright, trademark, or patent, can be modified, distributed, or sold without attribution
• Data Communications History:
• Johann Carl Friedrich Gauss (1777-1855):

  • German mathematician and physicist
  • Contributions to mathematics and sciences, including number theory, geometry, probability theory, and electromagnetism
• 1753: Proposal for a communication line between villages with 26 parallel wires representing each letter of the alphabet
• 1833: Carl Friedrich Gauss developed a system based on a 5x5 matrix representing 25 letters for sending messages in a single wire
• Samuel Finley Breese Morse (1791-1872):

  • American painter and inventor
  • Contributed to the invention of a single-wire telegraph system
  • Invented the telegraph in 1834, using binary coded electrical signals and Morse code
• 1840: Morse secured an American patent for the telegraph

  • 1844: First telegraph line established between Baltimore and Washington D.C.
  • Alexander Graham Bell (1847-1922):
  • Scottish-born American inventor, scientist, and engineer
  • Credited with inventing and patenting the first practical telephone in 1875
• Samuel Finley Breese Morse (1874-1937):

  • Italian inventor and radio pioneer
  • Guglielmo Marconi (1874-1937):
  • Italian inventor and electrical engineer
  • Succeeded in sending radio telegraph messages in 1899
• Network:
• Computer Network: two or more interconnected computers for sharing resources like databases and backup devices
• Elements of Computer Network:

  • Protocols: rules and agreements on network operation
  • Data and Messages: information transmitted in the network
  • Communications Medium: interconnects devices
  • Devices: computers, routers, switches, hubs, bridges
• Classification by Geographic Scope:

  • Personal Area Network (PAN)
  • Local Area Network: confined to one building or cluster of buildings, privately owned
  • Metropolitan Area Network: located within a city, use telecom or network service providers
  • Wide Area Network: located outside buildings, may span cities or countries
  • Global Area Network: computers in different countries worldwide
• Network Model:

  • Server: provides resources, data, services to clients
  • Client: makes requests to the server
• Two Basic Network Models:

  • Peer to Peer: all computers share resources
  • Dedicated Client/Server: one or more computers act as servers, others as clients
• Network Topology:

  • Physical Topology: physical layout of computers
  • Logical Topology: describes how data flows through the network
• Most Basic Topologies:

  • Point to Point: two stations connected
  • Multipoint: three or more stations connected
  • Physical Mesh, Star, Bus, Ring, Tree, Hybrid topologies
• The Internet:
• Internet: network of computer networks, worldwide communication network using common protocols

  • J.C.R. Licklider (1915-1990): American Psychologist and Computer Scientist