Microsoft® Windows® 2000 Security Handbook

What Is a Service?

A Windows 2000 service is an executable image that runs as a background task. Services are controlled by the Service Control Manager (SCM) and, for the most part, are independent of the user (or lack thereof) sitting at the console. Services can automatically start at the time of system boot, a user (using a number of tools) can manually start them, or some other program can start them programmatically.

Note

You'll notice my use of the term "for the most part" when I said that services are independent of any interactive user sessions. It is possible for a service to draw user-interface objects and interact with the console. However, it is widely considered poor programming practice to implement services that have a user interface ...