Installation Software - Types

Types

Attended installation

This is the most common form of installation. An installation process usually needs a user who attends it to make choices, such as accepting or declining an end-user license agreement (EULA), specifying preferences such as the installation location, supplying passwords or assisting in product activation. In graphical environments, installers that offer a wizard-based interface are common. Attended installers may ask users to help mitigate the errors. For instance, if the disk in which the computer program is be installed was full, the installer may ask the user to specify another target path.

Silent installation

Installation that does not display messages or windows during its progress. "Silent installation" is not the same as "unattended installation" (see below): All silent installations are unattended but not all unattended installations are silent. The reason behind a silent installation may be convenience or subterfuge. Malware is always installed silently.

Unattended installation

Installation that is performed without user interaction during its progress or with no user present at all. An unattended installation either does not require the user to supply anything or has received all necessary input prior to the start of installation. Such input may be in the form of command line switches or an answer file, a file that contains all the necessary parameters. Windows XP is an example of an operating system that can be installed with an answer file. In unattended installation, it is assumed that there is no user to help mitigate errors. For instance, if the installation medium was faulty, the installer should fail the installation, as there is no user to fix the fault or replace the medium. Unattended installers may record errors in a computer log for later review.

Headless installation

Installation performed without using a computer monitor connected. In attended forms of headless installation, another machine connects to the target machine (for instance, via a local area network) and takes over the display output. Since a headless installation does not need a user at the location of the target computer, unattended headless installers may be used to install a computer software on multiple machines at the same time.

Scheduled or automated installation

An installation process that runs on a preset time or when a predefined condition transpires, as opposed to an installation process that starts explicitly on a user's command. For instance, a system administrator willing to install a later version of a computer program that is being used can schedule that installation to occur when that program is not running. An operating system may automatically install a device driver for a device that the user connects. (See plug and play.) Malware may also be installed automatically. For example, the infamous Conficker was installed when the user plugged an infected device to his computer.

Clean installation

A clean installation is one that is done in the absence of any interfering elements such as old versions of the computer program being installed or leftovers from a previous installation. In particular, the clean installation of an operating system is an installation in which the target disk partition is erased before installation. Since the interfering elements are absent, a clean installation may succeed where an unclean installation may fail or may take significantly longer.

Network installation

An installation of a program from a shared network resource. This may simply be a copy of the original media but software publishers which offer site licenses for institutional customers may provide a version intended for installation over a network.