The last time you installed or removed a computer program there’s a good chance you used Windows Installer.
Windows Installer is a utility provided by Microsoft that manages an application’s installation and removal. It also allows for making modifications and repair of an application. It can be used as a command line utility as well as a service for managing the installation and removal of applications on the Microsoft Windows operating system.
Some of the advantages to Windows Installer include the set of consistent installation rules, better management of shared components and dynamic configuration and control.
Windows Installer is native to the Windows 2000, Windows ME and all later versions. It can be used in older versions of Windows such as Windows 95, Windows 98 and Windows NT by installing the appropriate Windows Installer service for the version you are working with.
For computers running Windows 95 or Windows NT 4.X, gaining the install on demand support of Windows Installer requires Windows Desktop Update. Unfortunately this is a pain if Windows Internet Explorer 5 or above is already installed because Windows Desktop Update is only available in Explorer 4.01 SP 1 with Active Desktop. This requires uninstalling Explorer 5 or above, installing Explorer 4, and then installing Windows Desktop Update. Finally after that is complete you must reinstall Internet Explorer 5 or above.
Windows Desktop Update is integrated into Windows 98 and above so no action is needed for computers using those operating systems.
Windows Installer enables user to easily install and configure software and applications. Software developers who take advantage of Windows Installer can advertise features without installing them, allow users to install products on demand and customize the installation.
Windows Installer allows developers to add a “rollback” feature to their software installation process. The rollback script that Windows Installer generates saves a copy of all files that were deleted during installation and keeps the files in a hidden system directory. Once the installation has successfully completed, the files are deleted. If the installation fails, Windows Installer automatically “rolls back” the installation and restores the system to its previous state.
Automatic rollback is the default choice of Windows Installer. Developers can disable automatic rollback if they wish.
Using the Control Panel to add and remove programs is a handy feature for many users. Developers can add configure Windows Installer so that the program can be used in the Add and Remove Programs section of the Control Panel. Depending on how the developer wants this to be handled, the software can be located in the Add and Remove Programs folder per user, per machine or not listed at all.
Another neat feature of Windows Installer is the ability to advertise the availability of a program without actually installing it. For an advertised but not installed program, only the interfaces for loading and launching the program are actually shown. For example, the Start menu will contain the shortcut and icons may be located on the desktop. When a user clicks the shortcut, the program installs on demand with Windows Installer.
The Windows Installer is familiar to users of the Windows operating system. Developers who choose Windows Installer understand the advantages for consistency in the Windows OS environment. The next time you install or remove a program from your computer, see if you can recognize the Windows Installer at work.