Remember this is for the 8088 chip, other platforms vary greatly when defining what a "byte" is - so you can imagine what else varies!

Starting from smallest to largest:

  • bit can hold one value either 1 or 0.
  • nibble can hold 4 bits.
  • byte can hold 2 nibbles. See also: octet
  • word can hold 2 bytes.
  • double word (dword) can hold 2 words.
  • quad word can hold 4 words.
  • ten bytes can hold 10 surprise surprise bytes.
Source: Teach yourself ... Assembler by Mark Goodwin ISBN: 1-55828-063-4


Erratum: I appear to have given the wrong chip number it's turns out this reference was for the 8088)! This is not mission critical to the defintions since the major difference (8086 and 8088) was their bus size 16 and 8bits respectively. I only wanted to clarify things. Also one last thing, the types after "word" maybe specifc to the domain of the Microsoft (MASM) and Borland (TASM) assemblers!

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