The Microsoft System Center Configuration Manager 2007 software distribution functionality allows system administrators to create packages for distributing software to client computers. A package generally represents a software application that will be installed on a client computer, but it might also contain individual files, updates, or even an individual command.
Using packages, your administrator can deliver, install, and configure software to meet the individual needs of you and your client computer. This is done using programs, which identify the actions that must occur on your computer once the package is received. Each program defines the client platform and environment within which the package can run, and includes any and all commands or files needed.
After programs have been defined for a package, the administrator creates an advertisement, which is sent to the client. The client user can then decide whether or not to download and run the program that's being advertised. In some cases, however, it's necessary for an administrator to create an assigned program, which is mandatory and must be installed on the client computer. Assigned programs are usually things like service packs, virus detection software, and other software that must be installed on the client because of network policy or security concerns. In most cases, when an assigned (mandatory) program is advertised, you will have the opportunity to download and run the program when it's convenient to you, but if it hasn't been done by a specific time set by the administrator, the program will automatically be run.