Fast-Access Storage

(also, zero-access memory), a section of the entire computer storage that has a capacity of a few tens or hundreds of machine words and whose access time is comparable to the time required to perform arithmetic or logical operations. A fast-access storage may be part of the main memory, or it may be a separate unit. It is used to accept and read back intermediate data and constants that are immediately used in the computation process. The fast-access storage is also used to store and modify the instructions in the part of the program being executed.