A-level OCR CS 1.1.3

• Examples of input devices:

  • Keyboard: Used to enter text into a computer
  • Webcam: A camera used by a computer to take photos and record videos
  • Magnetic stripe reader: Used to read data from magnetic stripes on cards like credit and debit cards
  • Barcode reader: Used in supermarket checkouts and access control systems to read information from printed labels and cards
• Examples of output devices:

  • Speakers: Used to output sound from a computer
  • Printers: Used to output information from a computer onto paper
  • Projector: Used to project video content from a computer onto a screen
• Some devices can be both input and output devices, like a touch screen that outputs information visually and acts as a device for touch input
• Important considerations when purchasing an input device:

  • Speed and accuracy of input
  • Ability to transfer data at faster rates or record information in greater detail
  • Cost and relevance for the task
• Optical storage:

  • Read from and written to using lasers
  • Binary information represented by reflecting or scattering laser light on spiral tracks
  • CDs: Compact discs using optical technology to store small quantities of information, commonly used for audio files, text, and digital images
  • DVDs: Digital versatile discs with higher storage capacity than CDs, suited for digital videos
  • Blu-Ray: Advanced discs with more storage capacity than DVDs, useful for high-resolution films
• Magnetic storage:

  • Represents binary information using polarised and unpolarised magnetic states
  • Hard Disk Drives (HDD): High-capacity storage devices rotating magnetic platters under a read/write head
  • Magnetic tape: Stores information magnetically, used in cassette tapes
  • Floppy Disks: Thin magnetic disks enclosed in plastic, portable for exchanging small amounts of data
• Flash storage:

  • Uses silicon semiconductors to store electrical charge in high or low states
  • NAND and NOR logic gates used to represent binary values
  • Solid State Drives (SSDs): Popular form of data storage with no moving parts, high data transfer rates, and resistance to damage from movement
  • Flash memory is non-volatile and can be erased and reprogrammed electronically
• Primary storage devices:

  • RAM (Random Access Memory): Fast main memory used to store data and programs currently in use, volatile and temporary storage
  • ROM (Read Only Memory): Non-modifiable memory used for fixed sequences of instructions, non-volatile and retains data even when powered off
• Virtual storage:

  • Storing information remotely for access by any computer with access to the same system
  • Examples include cloud storage services like Google Drive and Microsoft OneDrive
  • Virtual storage is an abstraction of multiple drives acting as one, convenient but limited by network speed and costs