Units Of Information

4.5.3 (6 questions). Public Notes: AQA's A Level Computer Science

Define bit.

The fundamental unit of information: 0 or 1.

Define byte.

A set of 8 bits.

Define nibble.

A set of 4 bits.

How many numbers can unsigned 7 bit binary represent.

  1. 2^7 = 128 numbers.
  3. 128 combinations of a set of 1s or 0s.

Write the series of values for binary prefixes: kibi, mebi, gibi, tebi.

  • Binary is base 2.
  • Therefore exponent increases in powers of ten.
kibi: 2^10, mebi: 2^20, gibi: 2^30, tebi 2^40

Write the series of values for decimal prefixes: kilo, mega, giga, tera

  • Decimal is base 10.
  • Therefore exponent increases in powers of three.
kilo: 10^3, mega: 10^6, giga: 10^9, tera: 10^12