1.2 memory and storage

• What are computer characters made up of?

  Numbers and alpha characters
• How are alpha characters ordered?

  Logically, with A lower than B
• What does ASCII stand for?

  American Standard Code for Information Interchange
• How is each character represented in ASCII?

  By a unique binary code
• How long is an ASCII code?

  8 bits (1 byte)
• What does using 2 bytes for a code allow?

  Many more possibilities for characters
• Why can ASCII accommodate languages like Arabic?

  It can represent thousands of characters
• Why must sound be encoded for computers?

  Computers only understand binary data
• How is sound broken down for encoding?

  Into thousands of samples per second
• What unit measures sound sampling?

  Hertz (Hz)
• What is the relationship between samples and sound clarity?

  More samples lead to clearer sound
• What does bit depth refer to in sound?

  Space needed for each sample
• How does higher bit depth affect sound quality?

  Higher quality but requires more space
• What does longer audio duration require?

  More storage space
• How is each pixel represented in images?

  As a series of points in binary
• How are shapes stored in images?

  As colors represented by specific codes
• What does image resolution refer to?

  Number of pixels in the image
• What happens to storage space with higher resolution images?

  More pixels require more space
• What does colour depth indicate?

  Number of bits used for colors
• How many colors can 1 bit represent?

  2 colors
• What does a higher colour space depth provide?

  More realistic colors but needs more space
• What is the purpose of encoding compression?

  To reduce space needed for storage
• What must happen to compressed data before use?

  It must be decompressed
• What is lossless compression?

  Compresses data without losing information
• What is a key feature of lossless compression?

  Original data can always be recreated
• Can all files be compressed using lossless methods?

  No, not all files can be compressed
• What is lossy compression?

  Compresses data with some loss of information
• Where is lossy compression typically used?

  In audio files where loss is acceptable
• What is a downside of lossy compression?

  Produces smaller files but poorer accuracy
• What is binary?

  A number system made of 1s and 0s
• Why do computers use binary?

  Because CPUs contain transistors that are on/off
• What is hexadecimal?

  A base 16 number system using 0-9 and A-F
• Why is hexadecimal used?

  To simplify long binary strings
• How many hex digits are in a nibble?

  1 hex digit per nibble
• What factors should be considered when choosing storage media?

  Capacity, speed, portability, durability, reliability, cost
• What does capacity refer to in storage media?

  How much data it can hold
• Why is speed important in storage media?

  For quick data access in live situations
• What does portability refer to in storage media?

  Ease of moving the media between devices
• What does durability refer to in storage media?

  How long the media is expected to last
• What does reliability refer to in storage media?

  How easily damaged the media is