Lifecycle phases do not necessarily happen in a linear order, and they can be intertwined in various ways. For example, when modifying a program, software developers may need to repeatedly edit, compile, install, and execute it on their own computers to ensure sufficient quality before it can be distributed to users; copies of the modified program are then downloaded, installed, and executed by users on their computers.
Phases
Edit time is when the source code of the program is being edited. This spans initial creation to any bug fix, refactoring, or addition of new features. Editing is typically performed by a person, but automated design tools and metaprogramming systems may also be used.
Compile time is when source code is translated into machine code by a compiler. Part of this involves language checking, such as ensuring proper use of the type system. The result of a successful compilation is an executable.
Link time connects all of the necessary machine code components of a program, including externals. It is very common for programs to use functions implemented by external libraries, all of which must be properly linked together. There are two types of linking. Static linking is when the connection is made by the compiler, which is always prior to execution. Dynamic linking, however, is performed by the operating system (OS) just before, or even during, execution.
Distribution time is the process of transferring a copy of a program to a user. The distribution format is typically an executable, but may also be source code, especially for a program written in an interpreted language. The means of distribution can be physical media such as a USB flash drive or a remote download via the Internet.
Installation time gets the distributed program ready for execution on the user's computer, which often includes storing the executable for future loading by the OS.
Load time is when the OS takes the program's executable from storage, such as a hard drive, and places it into active memory, in order to begin execution.
Run time is the execution phase, when the central processing unit executes the program's machine code instructions. Programs may run indefinitely. If execution terminates it will either be normal, expected behavior or an abnormality such as a crash.
Related Research Articles
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A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform.
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In computing, a linker or link editor is a computer system program that takes one or more object files and combines them into a single executable file, library file, or another "object" file.
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In computer science, an interpreter is a computer program that directly executes instructions written in a programming or scripting language, without requiring them previously to have been compiled into a machine language program. An interpreter generally uses one of the following strategies for program execution:
Parse the source code and perform its behavior directly;
Translate source code into some efficient intermediate representation or object code and immediately execute that;
Explicitly execute stored precompiled bytecode made by a compiler and matched with the interpreter's Virtual Machine.
In computing, cross-platform software is computer software that is designed to work in several computing platforms. Some cross-platform software requires a separate build for each platform, but some can be directly run on any platform without special preparation, being written in an interpreted language or compiled to portable bytecode for which the interpreters or run-time packages are common or standard components of all supported platforms.
In computer science, compile time describes the time window during which a language's statements are converted into binary instructions for the processor to execute. The term is used as an adjective to describe concepts related to the context of program compilation, as opposed to concepts related to the context of program execution (runtime). For example, compile-time requirements are programming language requirements that must be met by source code before compilation and compile-time properties are properties of the program that can be reasoned about during compilation. The actual length of time it takes to compile a program is usually referred to as compilation time.
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In computing, computer performance is the amount of useful work accomplished by a computer system. Outside of specific contexts, computer performance is estimated in terms of accuracy, efficiency and speed of executing computer program instructions. When it comes to high computer performance, one or more of the following factors might be involved:
The following outline is provided as an overview of and topical guide to the Perl programming language:
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