An instruction set architecture (ISA) is an abstract model of a computer, also referred to as computer architecture.A realization of an ISA is called an implementation.An ISA permits multiple implementations that may vary in performance, physical size, and monetary cost (among other things); because the ISA serves as the interface between software and hardware.

In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer.A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an implementation.. In general, an ISA defines the supported instructions, data types, registers, the hardware support for managing main memory, …