Windows service

Component of the Microsoft Windows operating system
In Windows NT operating systems, a Windows service is a computer program that operates in the background. Windows services can be configured to start when the operating system is started and run in the background as long as Windows is running. Alternatively, they can be started manually or by an event. Windows NT operating systems include numerous services which run in context of three user accounts: System, Network Service and Local Service. These Windows components are often associated with Host Process for Windows Services. Because Windows services operate in the context of their own dedicated user accounts, they can operate when a user is not logged on. Prior to Windows Vista, services installed as an "interactive service" could interact with Windows desktop and show a graphical user interface. In Windows Vista, however, interactive services are deprecated and may not operate properly, as a result of Windows Service hardening.

The command line tool to manage Windows services is sc. exe. It is available for all versions of Windows NT. This utility is included with Windows XP and later and also in ReactOS. The sc command's scope of management is restricted to the local computer. However, starting with Windows Server 2003, not only can sc do all that the Services snap in does, but it can also install and uninstall services. The ReactOS version was developed by Ged Murphy and is licensed under the GPL. + sc sub commands Name Description Windows support ReactOS support query Show service status ✔ ✔ queryex Show extended service info (e. g. pid, flags) ✔ ✔ start Start a service ✔ ✔ pause Pause a service ✔ ✔ interrogate Send an INTERROGATE control request to a service ✔ ✔ continue Continue a service ✔ ✔ stop Stop a service ✔ ✔ config permanently change the service configuration ✔ ✔ description Change a service description ✔ ✔ failure Change the actions taken by a service upon failure ✔ ✔ failureflag ✔ sidtype ✔ privs ✔ managedaccount ✔ qc Show the service config (e. g. dependencies, full path etc.) ✔ ✔ qdescription Query a service description ✔ ✔ qfailure ✔ qfailureflag ✔ qsidtype ✔ qprivs ✔ qtriggerinfo ✔ qpreferrednode ✔ qmanagedaccount ✔ qprotection ✔ quserservice ✔ delete Delete a service ✔ ✔ create Create a service ✔ ✔ control Send a control to a service ✔ ✔ sdshow Display a service's security descriptor using SDDL ✔ ✔ sdset Sets a service's security descriptor using SDDL ✔ ✔ showsid ✔ triggerinfo ✔ preferrednode ✔ GetDisplayName Show the service DisplayName ✔ ✔ GetKeyName Show the service ServiceKeyName ✔ ✔ EnumDepend Show the service Dependencies ✔ ✔ boot ✔ Lock ✔ QueryLock ✔

Windows also includes components that can do a subset of what the snap in, Sc. exe and PowerShell do. The net command can start, stop, pause or resume a Windows service. In Windows Vista and later, Windows Task Manager can show a list of installed services and start or stop them. MSConfig can enable or disable (see startup type description above) Windows services.

Windows services are installed and removed via *. INF setup scripts by SetupAPI; an installed service can be started immediately following its installation, and a running service can be stopped before its deinstallation.

For a program to run as a Windows service, the program needs to be written to handle service start, stop, and pause messages from the Service Control Manager (SCM) through the System Services API. SCM is the Windows component responsible for managing service processes.

The Windows Resource Kit for Windows NT 3.51, Windows NT 4.0 and Windows 2000 provides tools to control the use and registration of services: SrvAny. exe acts as a service wrapper to handle the interface expected of a service (e. g. handle service start and respond sometime later with service started or service failed) and allow any executable or script to be configured as a service. Sc. exe allows new services to be installed, started, stopped and uninstalled.