What is instruction set of computer?

Answer 1

The instruction set of a computer is the collection of commands that its Central Processing Unit (CPU) can carry out natively. These are the things that the processor inherently knows how to do if asked.

Answer 2

A computer's instruction set is typically defined by the built-in central processing unit's machine language, a set of typically primitive instructions for simple operations such as read and writing of data from and to memory, simple arithmetic and basic comparisons.

Most computer programs are written using a higher level language (which is translated into the machine language by a software development tool's compiler and assembler). The higher level language provides much more complex operations, for example as complex as matrix arithmetic.

Higher level programming languages are mostly standardized (or follow a quasi-standard), so that a given computer's particular set of machine language becomes increasingly irrelevant to software developers.

Answer 3

Commonly, an instruction set is a list of commands ready to be executed directly by CPU.