Windows Services
The following is a list of various types of information related to Windows Services that were compiled from various resources around the Web by AdvancedSetup
Many articles being from Microsoft knowledge base articles and forum posts so that a comprehensive presentation of knowledge about Windows Services would be available in a single resource.
Though not able to verify all information it is believed to be generally accurate.
Windows Services are one of the key components of Windows that allows the Windows Operating System to function. Though technically possible to run Windows without services it would not run well or be easily managed. Microsoft Windows services, formerly known as NT services, enable you to create long-running executable applications that run in their own Windows sessions.
They allow applications to run with or without a specific user logged onto the system. They can run under different local or network credentials to perform various tasks.
Start Wikipedia quoted
Service Control Manager (SCM) is a special system process under Windows NT family of operating systems, which starts, stops and interacts with Windows service processes. It is located in %SystemRoot%\System32\services.exe executable. Service processes interact with SCM through a well-defined API, and the same API interface is used internally by the interactive Windows service management tools such as the MMC snap-in Services.msc and the command-line Service Control utility sc.exe.
Implementation
The SCM executable, Services.exe, runs as a Windows console program, and is launched by the Wininit process early during the system startup. Its main function, SvcCtrlMain(), launches all the services configured for automatic startup. First an internal database of installed services is initialized by reading the following two registry keys: