Page "Nibble" Paragraph 5

The nibble is used to describe the amount of memory used to store a digit of a number stored in packed decimal format within an IBM mainframe.

This technique is used to make computations faster and debugging easier.

An 8-bit byte is split in half and each nibble is used to store one digit.

The last nibble of the variable is reserved for the sign.

Thus a variable which can store up to nine digits would be " packed " into 5 bytes.

Ease of debugging resulted from the numbers being readable in a hex dump where two hex numbers are used to represent the value of a byte, as 16 × 16 = 2 < sup > 8 </ sup >.