In computer science, an instance is an occurrence of a
software
Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications.
The history of software is closely tied to the development of digital comput ...
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: An object-oriented programming (OOP)
object created from a
class
Class, Classes, or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used d ...
. Each instance of a class shares a data layout but has its own memory allocation.
; Computer instance: An occurrence of a
virtual machine
In computing, a virtual machine (VM) is the virtualization or emulator, emulation of a computer system. Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve ...
which typically includes storage, a virtual
CPU.
; Polygonal model: In
computer graphics
Computer graphics deals with generating images and art with the aid of computers. Computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. ...
, it 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, it refers to an executing
process
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic.
Things called a process include:
Business and management
* Business process, activities that produce a specific s ...
. 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.
References
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Object (computer science)