Define the term Computer Architecture.

Computer architecture describes the attributes of a computer that a programmer can see and use. These are the instruction set, the number of bits used for data, the addressing modes, the registers and the way input and output is handled. It answers the question "what does the machine do?".

For example, whether a processor has a multiply instruction is an architectural decision. How that instruction is built with gates and circuits is not part of architecture. That is the job of computer organization. The same architecture can therefore be built with different organizations, as in the Intel x86 family over many years.