Editing Installation (computer programs) (section)

==Zero-install and portable applications==
As mentioned earlier, some computer programs need no installation. This was once usual for many programs which run on [[DOS]], the [[classic Mac OS]], [[Atari TOS]] and [[AmigaOS]]. As computing environments grew more complex and fixed [[hard drive]]s replaced [[floppy disks]], the need for tangible installation presented itself. For example [[Commodore International|Commodore]] released the [[Installer (programming language)|Installer]] for [[Amiga]].

The modern applications that can be run without going through formal process of installation and, in particular, do not require modifications of the [[operating system]], are sometimes referred to as '''zero-install'''.{{sfn|Eicher|2011|p=5}} Zero-install can be achieved through multiple means:
* a standard solution is to collect the application and its components together, copy them to a fixed [[Directory (computing)|directory]], and run from there.{{sfn|Oliveira|Martín-Rodríguez|2006|p=6}} In the case of [[Windows OS]] this approach is occasionally referred to as an "[[xcopy]] deployment";{{sfn|Eicher|2011|p=5}}
* a browser-based approach.

The [[Linux]] distribution [[GoboLinux]] takes a similar approach (each applications gets its own directory structure), but still introduces the side-effects of the traditional Linux installation to maintain the [[backward compatibility]] with the standard Linux directory layout. Isolation of the OS from any changes required by the application can also be achieved through the [[application virtualization]] tools, like [[VMware ThinApp]], [[Microsoft App-V]], InstallFree Bridge.{{sfn|Eicher|2011|p=11}}

A class of modern applications that do not need installation and are located on a detachable storage device are known as ''[[portable application]]s'', as they may be moved around onto different computers and run. Similarly, there are ''live operating systems'', which do not need installation and can be run directly from a [[bootable]] [[Compact Disc|CD]], [[DVD]], [[USB flash drive]] or loaded over the network as with [[thin client]]s. Examples are [[AmigaOS]] 4.0, various [[Linux distribution]]s, [[MorphOS]] or Mac OS versions 1.0 through 9.0. (See [[live CD]] and [[live USB]].) Finally, [[web application]]s, which run inside a [[web browser]], do not need installation.