Technical data

Glossary
accumulator: A register that accumulates data for arithmetic or logic
operations.
ALU: Arithmetic Logic Unit, a subset of the operation instruction function unit
that performs arithmetic and logical operations, usually in binary form.
Amdahl’s Law: A mathematical equation that states that a system is
dominated by its slowest process.
arithmetic exception: A software error that occurs while performing an
arithmetic or floating point operation.
array: Elements or data arranged in rows and columns.
array processor: A vector processor consisting of auxiliary hardware attached
to a host CPU. It is typically attached by an I/O bus and is treated by the
host as a foreign I/O device. Also called an attached vector processor.
asynchronous: Pertaining to events that are scheduled without any specific
time reference; not synchronized to a master clock. For example, while
performing arithmetic operations, the vector processor operates by an
asynchronous schedule to that of the scalar processor, which is free to
perform other operations.
benchmark: A program used to evaluate the performance of a computer for a
given application.
cache miss: The case when the processor cannot find an item in the cache
that it needs to perform an operation; also called a cache fault. When this
happens, the item is fetched from main memory at the slower main memory
speed.
chaining: A form of instruction overlap that uses a special hardware path
to load the output of one function unit directly into the input of a second
function unit, as well as into the destination register of the first instruction.
concurrent: Occurring during the same interval of time; may or may not be
simultaneous.
Glossary–1