Instance (computer science)

For other uses, see Instance (disambiguation).

In computer science, an instance is an occurrence of a software element that is based on a type definition. When created, an occurrence is said to have been instantiated, and both the creation process and the result of creation are called instantiation.

Examples

Class instance

A class instance is an object-oriented programming (OOP) object created from a class. Each instance of a class shares a data layout but has its own memory allocation.

Computer instance

A computer instance is an occurrence of a virtual machine which typically includes storage, a virtual CPU.

Polygonal model

A computer graphics polygonal model can be instantiated in order to be drawn several times in different locations in a scene which can improve the performance of rendering since a portion of the work needed to display each instance is reused.

Program instance

In a POSIX-oriented operating system, program instance refers to an executing process. It is instantiated for a program via system calls such as fork() and exec(). Each executing process is an instance of a program which it has been instantiated from.^[1]

References

1. Bach, Maurice J. (1986). The Design of the UNIX Operating System. Prentice Hall. pp. 10, 24. ISBN 0-13-201799-7. Archived from the original on 2010-03-15.