1.1.1 Data

• What is meant by analogue data?

  Analogue data is data represented in a physical way.
• What is meant by digital data?

  Digital data is represented as a combination of 1s and 0s.
• What is the relationship between analogue and digital data?

  Analogue data can be converted into digital data through sampling.
• What are examples of analogue data?

  • Grooves in a vinyl record
  • Shadows on a sundial
  • Vocal waves when speaking
  • Sound emitted from acoustic instruments
• How is analogue data stored on vinyl records?

  Analogue data is stored via grooves that represent continuous vibrations.
• What is the process called that converts analogue sound to digital data?

  The process is called sampling.
• What is the typical sampling frequency used on most audio CDs?

  44,000 times per second, or 44 kHz.
• What happens to audio files when they are compressed?

  Data is removed to reduce the size of the audio files.
• What is an analogue-to-digital (A/D) converter?

  An A/D converter is an electronic circuit that converts continuous signals into discrete digital numbers.
• What is a digital-to-analogue (D/A) converter?

  A D/A converter converts a digital signal into an analogue signal.
• What are the advantages of digital data?

  • Requires less physical space for storage
  • Easier to search and sort files
  • Allows for file copies and movement
  • Can be compressed for faster uploading/downloading
• What are the disadvantages of digital data?

  • Risk of losing files without proper organization
  • Potential loss of files due to hardware failure
  • Slow connections can hinder cloud storage access
• What are the advantages of analogue data?

  • No loss of data quality as it is continuous
  • Captures all nuances of the measured data
• What are the disadvantages of analogue data?

  • Quality can decline when copied or transferred
  • More physical space required for storage
• What is the effect of sampling rate on digital data quality?

  The higher the sampling rate, the better the quality of the sound recorded.
• What is a raster graphic?

  A raster graphic is a matrix data structure representing a grid of pixels.
• What is a bitmap image?

  A bitmap image is composed of many tiny parts called pixels.
• How is colour depth represented in a bitmap image?

  Colour depth is represented by how much red, green, and blue (RGB) is required for each pixel.
• What is the relationship between pixels per inch (PPI) and image quality?

  The more pixels per inch, the higher the resolution of the picture.
• What are the advantages of vector graphics?

  • Can be scaled without loss of quality
  • Use less storage space compared to raster graphics
• How are moving images recorded?

  Moving images are recorded by taking a quick series of images called frames.
• What types of moving image formats are mentioned?

  GIF, MOV, and MP4.
• What are the advantages of digital data storage?

  • Quick searching and sorting of files
  • Ability to create copies and move files
  • Data compression for space-saving
• What are the disadvantages of digital data storage?

  • Risk of losing files without proper organization
  • Potential loss of files due to hardware failure
  • Slow connections can hinder cloud storage access
• What are the advantages of data retrieval?

  • Quick searching through stored files
  • Sorting files by various criteria
  • Ability to create copies and move files
• What are the disadvantages of data retrieval?

  • Risk of losing files without proper organization
  • Potential loss of files due to hardware failure
  • Slow connections can hinder cloud storage access
• What are the advantages of data effectiveness?

  • Data can be compressed for less space
  • Faster uploading/downloading of files
  • Warning given before overwriting files
• What are the disadvantages of data effectiveness?

  • Fragmentation can increase access time
  • Files can be split across storage media
• What could happen if hardware fails?

  All the files could be lost.
• What issues can arise when using cloud storage?

  A slow connection or connection failure could cause delays or failures in storing data.
• What are the advantages and disadvantages of data compression?

  Advantages:

  • Compresses data to take up less space.
  • Allows faster uploading/downloading of files.
  • Retains quality while reducing file size.
  • Provides warnings before overwriting files.
  • Improves access time through defragmentation.

  
  

  Disadvantages:

  • Fragmentation can increase access time.
• What are the advantages and disadvantages of security measures for files?

  Advantages:

  • Password protection for files and folders.
  • Encryption of files for security.
  • Altering file properties to prevent changes.
  • RAID configurations protect against data loss.

  
  

  Disadvantages:

  • Digital data is susceptible to unauthorized access.
  • Cloud storage can be vulnerable without secure passwords.
  • Individuals can fall victim to attacks like social engineering.
• What are the advantages and disadvantages of accessibility in data storage?


  Advantages:

  • Specialist devices convert text data for users with alternative requirements.
  • Screen readers output text as audio.
  • Refreshable Braille displays convert text into Braille.
  • Device settings can be adjusted for accessibility.

  
  

  Disadvantages:

  • Not all programs work with accessible devices.
  • Accessible devices are often more expensive.
• What are the advantages and disadvantages of the ability to grow based on needs in data storage?


  Advantages:

  • Variable-sized files optimize storage space.
  • NAS devices allow for adding more storage as needed.
  • Cloud storage can be expanded by paying for more space.

  
  

  Disadvantages:

  • Variable-sized files are harder to design and manipulate.
  • Increasing NAS costs as storage needs grow.
  • Cloud storage costs increase with capacity.
• What is the difference between lossy and lossless compression?


  Lossless Compression:

  • Data can be decompressed without loss.
  • Preferred for critical data like text documents.

  
  

  Lossy Compression:

  • Discards some data to reduce file size.
  • Commonly used for multimedia data.
• How is lossless compression illustrated with a word-processed document?


  By replacing common strings with tokens to reduce size without losing data.
• What is the compression ratio formula?


  Compression ratio = Original file size ÷ Compressed file size
• What happens to image quality during lossy compression?


  Quality deteriorates as more data is discarded.
• What is the typical cost comparison of different storage types?

  Optical storage is cheap, magnetic is fairly cheap, and solid-state is expensive.
• What are the advantages and disadvantages of control in data storage?


  Advantages:

  • Set access level rights for different users.
  • Different file properties can be assigned.

  
  

  Disadvantages:

  • Appointing a systems manager can be costly.