1.1.3 Input, Output and Storage

• Topics covered

  • Input, Output and Storage Devices
  • The Use of Storage
• Input device


  One used to put data and information into a computer
• Output device


  One used to send information from the computer
• Output devices

  • Speakers
  • Printers
  • Projector
• Touch screen

  Outputs information in a visual way like a monitor and acts as a device for touch input
• Important things to consider when purchasing an input device include the speed and accuracy of input, transfer rates, recording detail, cost, and relevance
• Methods of storing information

  • Optical
  • Magnetic
  • Flash
• Optical devices

  Read from and written to using lasers, binary information represented by portions of the disc which either reflect or scatter the incident laser light
• Optical devices

  • CDs
  • DVDs
  • Blu-Ray
• CDs use optical technology to store small quantities of information, commonly used for audio files, text, and digital images. They are portable but easily damaged by scratches, have limited storage capacity, and relatively slow transfer speeds
• DVDs have a higher storage capacity than CDs, making them suited to storing digital videos which require more storage space than audio files or photos
• Blu-ray discs have more than five times as much storage than traditional DVDs, making them useful for storing high-resolution films
• Magnetic devices represent binary information using magnets
• Types of files that require more storage space

  • Videos
  • Audio files
  • Photos
• Blu-Ray

  • Advancement over DVDs, more than five times as much storage than traditional DVDs, useful for storing high-resolution films
• Magnetic storage devices

  • Represent binary information using two magnetic states: polarised and unpolarised
  • Can represent 1 and 0, allowing any information to be represented in binary form
• Common types of magnetic storage

  • Hard disk drives
  • Magnetic tape
• Hard Disk Drives (HDD)

  • Typically have high capacities between 500GB and 5TB
  • Work by rotating magnetic platters at high speeds under a read/write head on an actuating arm
  • Most HDDs have multiple platters stacked on top of each other to maximise storage capacity
  • Disadvantages include slow data transfer speeds and susceptibility to damage from movement
• Magnetic Tape

  • First used to record computer data in the 1950s
  • Popular storage medium until the 1980s
  • Tape was a bulky way to store data
  • Technology superseded by more modern technology like ROM cartridges
• Floppy Disks

  • Comprise a thin magnetic disk enclosed in plastic
  • Incredibly portable and popular for exchanging small amounts of data
  • Typical storage capacity of 1MB, some later versions had up to 200MB
• Flash storage

  • Fast and compact
  • Uses silicon semiconductors forming logic gates NAND and NOR to store electrical charge in high or low states
  • Information is stored in blocks, which are combined to form pages
• Preferred logic gate for storing small quantities of data

  NOR
• Preferred technology for larger files like photos and videos

  NAND
• Flash memory

  • Can be erased and reprogrammed electronically
  • Non-volatile, stores data even when power is lost
  • Good replacement for HDDs with improved performance
• Solid State Drives (SSDs)

  • Extremely light and portable
  • No moving parts, making them more resistant to damage
  • High data transfer rates
  • Good replacement for HDDs with improved performance
• SSDs

  • Reprogrammable electronically
  • Non-volatile, stores data even when power is lost
• Flash memory is similar to RAM but differs in that RAM is volatile while flash memory retains its information
• Flash memory is more expensive per gigabyte than other data storage methods like magnetic and optical
• RAM (Random Access Memory)

  • Type of fast main memory used to store data and programs currently in use
  • Higher access speeds than flash memory
  • More expensive per gigabyte than secondary storage devices
• RAM

  • Volatile, loses information when power is lost
  • Used for temporary storage while the computer is running
• ROM (Read Only Memory)

  • Cannot be modified once programmed
  • Useful for storing fixed sequences of instructions like a computer's startup routine
  • Non-volatile, retains data even when the computer is powered off
• Virtual storage is the name given to storing information remotely for access by any computer with access to the same system
• Virtual storage

  • Cloud storage services like Google Drive and Microsoft OneDrive
  • Networked storage used in offices and schools
• Virtual storage

  • Abstraction of multiple drives acting like one
  • Convenient to access and share
  • Information stored in the cloud is actually stored on multiple hard drives or SSDs formatted to act as a single piece of storage
• Increasing internet speeds


  Virtual storage is becoming a more popular method of storage
• Virtual storage

  Disadvantages include limitations of a user's network speed and high costs
• Explain why virtual storage is well-suited for storing backups.(3 marks)

  • Stored away from the computer so in case of disaster the data is not damaged
  • Can be accessed from elsewhere
  • No physical space needed for backup hardware