Build the Installation Program Immediately

Begin developing the installation program immediately after you start developing your project. The installation program is the first part of your product that your users see. Too many products give a poor first impression, showing that the installation program was left to the last minute. By getting the installation program started as early as possible, you have sufficient time to test and debug it. If the installation program is done early, you can also incorporate it into your smoke test. This way, you're always testing it and your tests will be one step closer to simulating how the users will be running your program.

Earlier in the chapter, I recommended that you should build both release and debug versions of your product. You also need to have an installation program that allows you to install either version. Even though managed applications have the vaunted XCOPY installation, that's only for baby programs. Real-world managed applications are going to have to initialize databases, put assemblies in the global assembly cache, and handle other operations that just can't be done with a simple copy. Of course for native applications, don't forget that COM is still alive and kicking; COM needs so much stuff in the registry that it's almost impossible to properly use an application without running its installation program. By having a debug build installation program, developers can easily get a debug version on a machine so that they can quickly start debugging a problem.

One extra benefit of having the installation program done as early as possible is that others in your company can start testing your program that much sooner. With the installation program done, the technical support engineers can start using your program and providing you with feedback early enough in the cycle so that you can actually do something about the problems they find.