Essentials of Computer Organization and Architecture, 5th Edition

2.6   CHARACTER CODES

We have seen how digital computers use the binary system to represent and manipulate numeric values. We have yet to consider how these internal values can be converted to a form that is meaningful to humans. The manner in which this is done depends on both the coding system used by the computer and how the values are stored and retrieved.

2.6.1   Binary-Coded Decimal

For many applications, we need the exact binary equivalent of the decimal system, which means we need an encoding for individual decimal digits. This is precisely the case in many business applications that deal with money—we can’t afford the rounding errors that occur when we convert real numbers to floating point during financial transactions!

Binary-coded ...