topic 2

• System unit


  A case that contains electronic components of the computer used to process data
• Computer


  An electronic device that processes data into information
• Mobile device


  An electronic device that a user can walk around with
• Personal computer


  A device that is intended to be used by one person
• Desktop PC


  • Designed to be stationary on a desk
  • Utilizes peripheral devices for interaction, such as a keyboard and mouse for input, and display devices like a monitor, projector, or television
• Laptops


  • A thin, lightweight mobile computer with a screen in its lid and a keyboard in its base
  • Designed to fit on the lap and to be portable
  • All other functionalities are integrated on one unit
• Tablet/Tablet PC


  • Usually smaller than a laptop but larger than a smartphone
  • Thin, lightweight mobile computer that has a touch screen
  • Tablet PC has a detachable keyboard
  • Tablet PC may use a stylus pen
  • Useful in meetings and or in transit
• Handheld computers


  • A computer small enough to fit in one hand
  • Communicates wirelessly with other devices or computers
  • Many handhelds are industry specific and serve the needs of mobile employees, such as parcel delivery people or warehouse employees
• Servers


  • A computer dedicated to providing one or more services to other computers or devices on a network
  • Services provided by servers include storing content and controlling access to hardware, software and other resources on a network
• Types of servers


  • Rack server
  • Blade server
  • Tower server
  • Virtual servers
  • Server farm
  • Mainframe server
• Virtual servers


  • Uses software to configure and emulate physical servers
• Server farm


  • A network of servers together in a single location
  • Makes it possible to combine the power of multiple servers
• Mainframe server


  • A large expensive, powerful server that can handle hundreds or thousands of connected users simultaneously
• Terminals


  • Designed for a specific purpose
  • Examples: POS - Point of Sale, ATM - Automated Teller Machine, SSK - Self Service Kiosk
  • Contains a host computer which processes input
  • Input might be touch, keyboard/brail keyboard/voice
  • Limited capabilities
  • Screen usually small
• Supercomputer


  • Has internally large storage capacity and computing speed
  • Fastest computer in the world because supercomputer has ten thousand processors which can do millions and billion calculations per second
  • IBM Sequoia Petascale Blue Gene/Q supercomputer has a speed of 20.13 PFLOPS
  • Built with the purpose of nuclear weapons, astronomy, energy, human genome, and climate change
  • Costs 250 million dollars
  • One petaFLOPS is equal to 1,000,000,000,000,000 (one quadrillion) FLOPS - floating point operations per second is a measure of computer performance
• Cloud computing


  • Refers to an environment of servers that house and provide access to resources users access through the internet
  • Resources include email messages, schedules, music, photos, videos, games, websites, programs, web apps, servers, storage, and more
  • Provides accessibility, cost savings, space savings, and scalability
• Mobile devices


  • Smartphones are portable with multiple apps and functionalities, touch screen, integrated with a digital camera, multimedia player etc, and connected to the internet
  • Wearables
• Ports


  The point at which a peripheral device attaches to or communicates with a computer or mobile device so that the peripheral device can send data to or receive information from the computer or mobile device
• Hardware protection measures


  • Physical access controls
  • Alarm system
  • Physical security devices
  • Security or device-tracking app
  • Require identification
• Reasons for hardware failure

  • Aging hardware
  • Random events such as electrical power problems
  • Errors in programs or apps
• Electrical faults


  • Undervoltage
  • Overvoltage
  • Power surge
• Surge protector


  Protects against power surges
• Uninterruptible Power Supply (UPS)


  Protects against power failures
• Health hazards


  • Repetitive strain injury (RSI)
  • Computer vision syndrome (CVS)
  • Technology addiction
• Ergonomics


  An applied science devoted to incorporating comfort, efficiency, and safety into the design of items in the workplace
• Motherboard


  The main circuit board on which all other electronic components, ports and sockets are connected to
• Processor/Central Processing Unit (CPU)


  • Carries out and interprets basic instructions that operate a computer
  • Most devices connected to the computer communicate with the CPU to carry out a task
  • A multi-core processor is a single chip with two or more separate processor cores
• Machine cycle


  1. Fetching - obtaining a program or application instruction or data item from memory

  2. Decoding - translating the instruction into signals the computer can execute

  3. Executing - carrying out the commands

  4. Storing - writing the results to memory
• Registers


  Small, high speed storage locations in the processor
• System clock


  • A small quartz crystal circuit that controls the timing of all computer operations
  • Each tick equates to a clock cycle
  • Processors today are typically superscalar, which means they can execute more than one instruction per clock cycle
  • The pace of the system clock is called clock speed
• Heat sink


  • A small ceramic or metal component with fins on its surface that absorbs and disperses heat produced by electrical components, such as the processor
• Liquid cooling technology


  Uses continuous flow of fluid(s), such as water and glycol, to transfer heated fluid away from the processor to a radiator-type grill, which cools the liquid, and then returns the cooled fluid to the processor
• Cooling pads


  Rests below a laptop and protects the computer from overheating and also the user's lap from excessive heat
• Bit


  The smallest unit of data
• Byte


  A series of bits that represents data
• Categories of items stored in memory

  • Operating System and other programs that control or maintain the computer and its devices
  • Applications that carry out specific tasks
  • Data being processed by the applications and the resulting information
• Volatile memory


  Loses its content when the computer's power is turned off
• Non-volatile memory


  Does not lose its contents when power is removed from the computer
• Random Access Memory (RAM)

  • Also called main memory
  • When the computer is powered on, certain operating system files are loaded from storage devices onto RAM
  • Dynamic RAM (DRAM) chips must be reenergized constantly or they lose their contents
  • Static RAM (SRAM) chips are faster and more reliable than any variation of DRAM chips
• Cache memory


  Helps speed the process of the computer by storing frequently used instructions and data