Module 7

• Computers and devices use both storage and memory to access and save data and information
• Memory


  Electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processing the data into information
• Storage


  Long-term, permanent access to data and information
• Storage medium


  Nonvolatile, the location where a computer keeps data, information, programs, and applications
• Cloud storage


  Keeps information on servers on the Internet
• Storage device


  Hardware that records and/or retrieves items to and from storage media
• Writing


  Process of transferring data, instructions, and information from memory to a storage medium
• Reading


  Process of transferring data, instructions, and information from a storage medium into memory
• Capacity


  Number of bytes (characters) a storage medium can hold
• Storage terms


  • Kilobyte (KB)
  • Megabyte (MB)
  • Gigabyte (GB)
  • Terabyte (TB)
  • Petabyte (PB)
  • Exabyte (EB)
  • Zettabyte (ZB)
  • Yottabyte (YB)
• Access time


  Amount of time it takes for a storage device to locate an item on a storage medium, and the time required to deliver an item from memory to the processor
• Transfer rate


  Speed with which data, instructions, and information transfer to and from a device
• Hard drives


  • Most common storage medium
  • Can store data either magnetically or using solid-state storage
  • Files stored on internal hard drive cannot be accessed on other devices

  
• Magnetic hard disk drives (HDDs)


  Greater storage capacity and less expensive than solid-state equivalents
• Hard disk


  Storage device that contains one or more inflexible, circular platters that use magnetic particles to store data, instructions, and information

  
• Platter


  • Made of aluminum, glass, or ceramic with a thin coating of alloy material that allows items to be recorded magnetically on its surface
• Longitudinal recording


  Aligns the magnetic particles horizontally around the surface of the disk
• Perpendicular recording


  Aligns the magnetic particles vertically or perpendicular to the disk's surface
• Density


  Number of bits in an area on a storage medium, higher density means more storage capacity
• Formatting


  Process of dividing the disk into tracks and sectors
• Track


  One of the series of concentric circles on one of the surfaces of a magnetic hard disk platter
• Sector


  Individual block of data or a segment of a track
• Hard disk


  • Multiple platters, each with two read/write heads, one for each side
  • Hard disk head actuator connects to arms that move the read/write heads to the correct location on the platter
• Hard disk operation


  • Platters rotate at a high rate of speed to allow nearly instant access to all tracks and sectors
  • Spinning motion creates a cushion of air between the platter and its read/write head
• External hard drive


  • Separate, free-standing storage device that connects with a cable to a USB port or other port on any device
• SSD (solid-state drive)


  Flash memory storage device, consists entirely of electronic components and contains no moving parts
• Memory card


  • Removable flash memory storage device that enables mobile users to easily transport digital content to and from mobile devices and computers
• USB flash drive


  • Removable storage device for folders and files that plug in a USB port on a computer
• Optical media


  • CDs
  • DVDs
  • Blu-ray discs (BDs)
• Optical disc


  Type of storage medium that consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

  
• Optical media


  CDs, DVDs, and Blu-ray discs (BDs), but their use as storage media is declining
• Optical disc


  A type of storage medium that consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

  
• Optical disc formats


  • CD-ROM (read-only)
  • CD-R (recordable)
  • CD-RW (rewritable)
  • DVD-ROM (read-only)
  • DVD-R, DVD+R (recordable)
  • DVD-RW, DVD+RW, and DVD+RAM (rewritable)
  • Higher capacity disc than DVD
• HDD


  Hard Disk Drive, a storage device

  
• SSD


  Solid State Drive, a storage device
• Home and business users choose cloud computing for accessibility, cost saving, space saving, and scalability
• Cloud computing


  Consists of a front end and a back end, connected to each other through a network
• Front end

  Includes the hardware and software with which a user interacts to access the cloud
• Back end


  Consists of the servers and storage devices that manage and store the resources accessed by users
• Cloud computing allows companies to outsource, or contract to third-party providers, elements of their information technology infrastructure