Memory and storage

• Non-volatile memory will not be deleted when the power is switched off
• Volatile memory is only temporary and the contents are deleted when the power is switched off
• A denary number system uses 10 digits (0-9) to represent the value.
• A binary number system uses 2 digits (0 and 1) to represent the value.
• A hexadecimal number system uses 16 digits (0-9 and A-F) to represent the value.
• Characters of a similar type (upper case, lower case or numeric digits) run in a sequence within a character set
• How sound can be sampled and stored in a digital form

  To store this as a digital sequence a sample must be taken of the sound wave at set intervals. Using our wave from above we may say this is a sound wave over the period of 1 second so we can split that second down into smaller parts.
• Sample rate

  Number of samples taken in a second, measured in hertz (Hz)
• Bit depth

  The number of bits per sample, also known as the resolution
• Calculate sound file sizes

  Rate = sample rate

  Bit depth = sample resolution

  Time = number of seconds

  File size = rate*bit depth*time
• Compressing a file is when a file is encoded so it uses fewer bits than the original file format