Advertising—also known as install-on-demand—is a feature of the Windows Installer technology that announces the availability of an application without actually having the application installed on the PC. Announcing the application is performed by using a couple different methods. First, the application can be designated to be installed completely on specified computers, and second, it can be configured to appear as an icon in the computer’s START | Programs menu and installed when the end user attempts to access the application. Advertising can be used for an entire application or for individual features such as a spellchecker or clip art.
There are two types of advertising: assigning and publishing.
Assigning. Assigning makes an application available, and it appears to a user as if it has been installed without it actually having been installed. The application’s icon shows up in the START | Programs folder and can be installed when the end user attempts to execute the application’s program. Assigning (as opposed to publishing) an application forces it to be automatically installed for all specified accounts or for a single user.
Publishing. Publishing an application advertises it to the members of a group specified in the Group Policy setting by adding the application to the list of available programs in Add/Remove Programs. The next time the members of the group open Add/Remove Programs, they have the option to install the new applications.
Group Policy allows only specific file formats to be distributed through the software distribution mechanism. These file types are based on the Microsoft Windows Installer technology, which is a groundbreaking service that allows applications to be managed automatically. In the past, applications followed no known standard for installing and caused problems for other applications and other functions of the operating system. For example, there are a number of applications that rely on specific versions of system files to operate correctly. An installation would install its own required version without any regard to existing files. This procedure would break other applications and also cause the operating system to stop functioning properly. And when the application was uninstalled, those same share files would be removed even if other applications required their existence.
Group Policy uses MSI files for distribution to clients. The Windows Installer service recognizes the following file types:
MSI. An MSI file is a database that contains the installation information of an application. All information about that installation is contained within the database, such as registry modifications, file installs, file registrations, user interface, and installation options.
Transform. A transform is a collection of changes applied to an installation. By applying a transform to a base installation package, the installer can add or replace data in the installation database. The installer can apply transforms only during an installation. This allows an organization to modify how an application is installed so that the default installation contains different options than what the CD-based installation would contain.
Note: Non-MSI programs can be published only to users and are installed by using their existing Setup programs. To publish a non-MSI application, you must first create a ZAP (Zero Administration for Windows—ZAW—downlevel applications package) file. The ZAP file is a reference file that Active Directory uses to create non-MSI publications. Because non-MSI programs use their existing Setup programs, these programs lose the ability to take advantage of the following MSI features:
Elevated privileges for installation
Installation on the first use of the software
Installation of a feature on the first use of the feature
Rollback support for an unsuccessful operation (install, modify, repair, or removal)
Software resiliency (missing or corrupted applications files or library files)
For more information about ZAP files, see http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnexnt00/html/ewn0085.asp.
Group Policy Example: Distributing Office XP
You can use Group Policy Objects (GPOs) to assign Office XP programs to users or computers in Active Directory. When users first log on to their computers after you’ve assigned the Office XP programs, the programs are made available to the users.
You can use Group Policy to deploy and manage Office XP programs by using a GPO. After you set a policy for Office XP programs, they’re applied automatically.
Assigning Office XP to users ensures that they’ll have access to the same Office XP programs and features no matter which computer they log on to. Once you’ve assigned Office XP to users, information about the software is displayed on the users’ desktop or Start menu the first time they log on. Clicking a shortcut starts the Windows Installer service, which then automatically installs the program according to policy settings.
For more information about performing this operation, see the article, “Use IntelliMirror in Windows 2000 to Deploy Office XP Programs by Using a Group Policy Object” (http://support.microsoft.com/default.aspx?scid=kb;en-us;312972&sd=tech).
Windows Server 2003 Group Policy
In conjunction with Windows Server 2003, Microsoft is releasing a new Group Policy management solution that unifies management of Group Policy. The Microsoft Group Policy Management Console (GPMC) provides a single solution for managing all Group Policy-related tasks. GPMC lets administrators manage Group Policy for multiple domains and sites within a given forest, all in a simplified user interface with drag-and-drop support. Highlights include new functionality such as backup, restore, import, copy, and reporting of GPOs. These operations are fully scriptable, which lets administrators customize and automate management. Together, these advantages make Group Policy much easier to use and help you manage your enterprise more cost-effectively.
In addition to the new console to improve management of Group Policy, Microsoft has improved specific areas in relation to software distribution. Although the additions don’t represent a full rewrite of Group Policy, they do signify some improvements. Windows Server 2003 offers:
Improved behavior. Windows Server 2003 includes a full install at Logon option. This improvement forces a full installation of an application and helps avoid the risk of needing to fault-in a component while not online.
Security. The option Remove previous installs of this product from computers, if the product was not installed by Group Policy-based Software Installation is no longer present. Now previously installed versions are always completely removed before any attempts are made to install software.
New feature. Administrators can now specify or customize the Support URL that appears with an application in the Add/Remove Programs Control Panel applet.