Any system administrator tired of different methods of program installation, probably, looks closely at Microsoft Software Installer (MSI). Developing the product Microsoft company brought order to the process of software installation and made it consistent and stable.

Windows Installer was developed between 1995 and 1998 and had the Darwin code name at the beginning. The recent versions were named Microsoft Installer with .msi default file extension of the installation package. The very first version of the Installer was released at 1999.

Windows Installer was a significant step forward relative to the previous Microsoft installer - Setup API (ACME Setup): it included a GUI framework, an uninstall support and a possibility to go back to any point of the installation process (including the rollback during uninstall), a correct work with access rights in Windows and other opportunities, so that this product was a strong alternative to the installation packages available on the market.

A MSI file contains database spreadsheets which describe the application. In many cases, the MSI file also includes some program files. This makes the installation process more flexible. During the installation the users can select parts of the application they want to install to their systems. The installation package includes such components as registry parameters and COM (Component Object Model) objects.

The main advantage of MSI is the standardization of the software installation process: it sends to the past proprietary installation formats. Other advantages of MSI are listed below:

• The WIS service (Windows Installer Service) performs the installation of applications on the basis of transactions. This means that it monitors added, replaced, deleted files and registry settings. If a fatal error occurs during the installation, MSI allows you to cancel the process in order to avoid a malfunction of the system with a half-installed components.
• Using the MSI together with the Active Directory service it's possible to link it to a group policy, enabling end users to install applications to their desktop systems even without permissions to modify the file system and registry. In this case the installation request goes to the WIS service which practically proceeds with the installation. As the installation package has been approved by the administrator, for example, by the link to the AD group policy, the installation process will run smoothly.
• The MSI format gives a possibility to configure and customize the installation process through the MSI-transform creation. MSI-transform is a file with .mst extension containing the instructions for the WIS service concerning the MSI installation. This file indicates the package options that should be installed, the place where the package should be located or sets responses for dialog boxes. It's more convenient to create a MSI- transform than modify the original MSI package. Moreover it's possible to create different transformations for one MSI file.
• Software developers, who use the MSI format, can profit the advanced features of MSI, such as self-healing after a crash or determination of the application options, installed with the first launch. But these opportunities require the use of MSI programming interfaces.

We offers to corporate customers a MSI package with its popular viewer to download.

MSI supports some public properties, which you can use by command line or Group Policy installation

• MAIN_APP_FOLDER - path to destination folder
• USERNAME - user name (from license information)
• EMAIL - e-mail (from license information)
• KEY - key (from license information)
• SHORTCUT_DESKTOP - add shortcut to the users desktop (if you don't want to add shortcut, use SHORTCUT_DESKTOP="" in command line)
• SHORTCUT_PROGRAMMENU - add shortcut to the Start menu
• DEF_VIEWER_EXT - files extensions divided by semicolon - list of extension for which STDU Viewer as default application.