Windows service

In Windows NT operating systems, a Windows service is a computer program that usually operates in the background without user interaction. 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. They are similar in concept to a Unix daemon. 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. Service Control Manager is the Windows component in charge of starting and ending Windows services.

Administration

Installed services can be managed by "Services" applet include in the Windows Control Panel, Administrative Tools, Windows PowerShell or by several command line tools included in Microsoft Windows. Other Windows components such as MSConfig and Windows Task Manager (in Windows Vista and later) have limited Service management powers.

The "Services" applet, built upon Microsoft Management Console, enables users to:^[1]

• See a list of installed service along with service name, descriptions and configuration
• Start, stop, pause or restart services^[2]
• Specify service parameters when applicable
• Change the startup type. Acceptable startup types include:
  • Automatic: The service starts at system logon.
  • Automatic (Delayed): The service starts a short while after the system has finished starting up. This option was introduced in Windows Vista in an attempt to reduce the boot-to-desktop time. However, not all services support delayed start.
  • Manual: The service starts only when explicitly summoned.
  • Disabled: The service is disabled. It will not run.
• Change the user account context that the service operates in
• Configure recovery actions that should be taken if a service fails
• Inspect service dependencies, discovering which services or device drivers depend on a given service or upon which services or device drivers a given service depends
• Export the list of services as a text file or a CSV file
• Manage services on the local computer or on a remote computer over a network.^[1]

There are also two command-line interface programs included in many versions of Windows that can control or configure services. The most powerful one is sc.exe, which was formerly a part of the Windows Resource Kit.^[3] Starting with Windows Server 2003, not only can sc.exe do all that the “Services” applet did, but it can also install and uninstall services.^[4] The other one is net.exe, which can start, stop, pause or resume a service.^[2]

Also, the Windows PowerShell (introduced in Windows 7) can intrinsically manage Windows services via the following cmdlets:

• Get-Service^[5]
• New-Service^[6]
• Restart-Service^[7]
• Resume-Service^[8]
• Set-Service^[9]
• Start-Service^[10]
• Stop-Service^[11]
• Suspend-Service^[12]

In addition to these four, Windows also includes components that can partially manage certain aspects of services. 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.

Development

A Windows service can be created using development tools such as Microsoft Visual Studio or Embarcadero Delphi. In order to be a Windows service, a program needs to be written in such a way that it can handle start, stop, and pause messages from the Service Control Manager. The Service Control Manager is a component of Windows which is responsible for managing, starting and stopping services.

See also

Windows services

• Daftar/Tabel -- Microsoft Windows components § Services
• Windows Service Hardening

Concept

• Daemon (computer software)
• Operating system service management
  • FireDaemon
  • Service Control Manager
  • Service Management Facility
• Service Wrapper

References

Further reading

• "Services". Microsoft Developer Network. Microsoft. Retrieved 29 March 2013. 
• Savill, John (5 March 1999). "What are the ErrorControl, Start and Type values under the Services subkeys?". Windows IT Pro. Penton Media. Retrieved 29 March 2013.