Software Installation and Maintenance

Windows Installer

Windows 2000 uses Windows Installer technology, which uses the following components to install, manage, and maintain software:

An operating system service that performs the installation, modification, and removal of the software in accordance with the information in a Windows Installer package.
The Windows Installer package (an .msi file), which is a database containing information that describes the installed state of the application.
An application programming interface (API) that allows applications to interact with Windows Installer to install or remove additional features of the application after the initial installation is complete.

Note

Windows Installer is a base service of the Windows operating system; therefore, it is available with Windows 2000, Microsoft® Windows NT® version 4.0, Microsoft® Windows® 98, and Microsoft® Windows® 95.

Windows Installer works by managing the state of the installation. Because Windows Installer knows the state of the software, it can ensure that the software is installed correctly. If there is a problem during installation, Windows Installer can roll back the installation, ensuring the computer is left in a working (known good) state. The management of state also allows you to modify the installation, adding or removing features after installation. Because Software Installation uses Windows Installer, users can take advantage of self-repairing applications. Windows Installer notes when a program file is missing and immediately reinstalls the damaged or missing files thereby fixing the application. And finally, using the state of installation to manage the installation also allows for complete removal of the software when it is no longer needed.

For more information about Windows Installer, see "Windows Installer Technology" later in this chapter.