GCSE Computing/Representation of Data in Computer Systems

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Section 2.1.4 Representation of data in computer systems[edit | edit source]

Topics[edit | edit source]

Units[edit | edit source]

  • (a) Define the terms
  • bit,
  • nibble,
  • byte,
  • kilobyte,
  • megabyte,
  • gigabyte,
  • terabyte.

(b) understand that data needs to be converted into a binary format to be processed by a computer.

  • (c) Convert positive denary whole numbers (0-255) into 8-bit binary numbers and vice versa
  • (d) Add two 8-bit binary integers and explain overflow errors which may occur
  • (e) convert positive denary whole numbers (0-255) into 2-digit hexadecimal numbers and vice versa
  • (f) convert between binary and hexadecimal equivalents of the same number
  • (g) explain the use of hexadecimal numbers to represent binary numbers.

Character[edit | edit source]

Candidates should be able to:

  • (h) explain the use of binary codes to represent characters
  • (i) explain the term character set
  • (j) describe with examples (for example ASCII and Unicode) the relationship between the number of bits per character in a character set and the number of characters which can be represented.

Images[edit | edit source]

Candidates should be able to:

  • (k) explain the representation of an image as a series of pixels represented in binary
  • (l) explain the need for metadata to be included in the file such as height, width and colour depth
  • (m) discuss the effect of colour depth and resolution on the size of an image file.

Sound[edit | edit source]

Candidates should be able to:

  • (n) explain how sound can be sampled and stored in digital form
  • (o) explain how sampling intervals and other considerations affect the size of a sound file and

the quality of its playback.

Instructions[edit | edit source]

(p) explain how instructions are coded as bit patterns (q) explain how the computer distinguishes between instructions and data