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How are these fundamentally different "things" on Windows?

Aren't all running things Processes?

It seems that every Application has an associated process that shuts it down if it is shut down. It looks like one process can manage more than one application instance. And Services, I'm not even sure what they are, exactly.

Are they not processes themselves?

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Both applications and services have processes associated with them.

An application is a program which you interact with on the desktop. This is what you spend almost all of your time using on the computer. Internet explorer, microsoft word, iTunes, skype - they are all applications.

A process is an instance of a particular executable (.exe program file) running. A given application may have several processes running simultaneously. For example, some modern browsers such as google chrome run several processes at once, with each tab actually being a separate instance/process of the same executable. In some cases, complicated applications may have multiple processes; for example, Visual Studio runs a separate process when it compiles code from when it displays the IDE. However, most often, a given application is running from a single process; for example, no matter how many microsoft word windows you have open, only a single instance of winword.exe is running.

A service is a process which runs in the background and does not interact with the desktop. In Windows, services almost always run as an instance of the svchost.exe process, the windows service host process; however there are sometimes exceptions to this.

Sometimes, processes may run in the background without interacting with the desktop, but without being installed as a service. Many device drivers with enhanced features do this. For example, a touchpad driver will usually have a process which runs when a user logs in and handles the special features of the touchpad, but isn't a service and doesn't show any windows to the user.

Sometimes an application may depend on a certain service. Printing from any program requires that the print spooler service be active. Installation packages (.msi installers) require that the windows installer service be running. Antivirus programs usually employ a service so they can continue running even when the user is not logged in.

Processes usually exit when an application is closed, however this is not always the case. Some programs, particularly download and backup programs, may continue to run in the background without displaying any windows. Antivirus is also an example of this - in addition to using a service, many antivirus applications run a process silently in the background which only displays an application to the user when action is required.

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    Then whats the difference between a silent process and windows service? Sorry I'm new! Aug 14, 2013 at 7:16
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    A Service will have more rights than a normal process as it runs as a Windows proces and not a User proces. Dec 14, 2016 at 16:14
  • @GillesLesire So, Services are akin to Drivers than? In that its run from the elevated Windows proc? So its effectively a middle link between UserSpace Application and a Driver? Aug 15, 2022 at 14:15
  • @ScienceDiscoverer i guess one way to see it is that services and everything else running in user mode is just this - some code running in user mode... The os schedules processes and their threads for running. What the conceptual task of the thread or process is, how it is classified ("app" or service), how long it runs etc is up to the designer of the code and almost anything imaginable works and exists. THE OS KERNEL DOES NOT CARE. This is particularly true in unix where there is not even a concept of service and traditionally not even a thread and process distinction from the kernel's pov.
    – masterxilo
    Oct 15, 2023 at 11:04
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Both applications and services are processes. Applications are meant to interact with a single user, whereas services work across the system, but don't interact with users directly.

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    Most Windows services run as svchost.exe, but I've not seen too many non-Windows services that do. It should be noted that Sysinternal's Process Explorer can be used to determine what services in the Services MMC console are hosted by a specific svchost.exe.
    – LawrenceC
    Mar 14, 2011 at 12:18
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A service is usually a background application that runs when windows starts up. usually it performs some task that installed applications or windows itself uses.

A stand alone application is just a normal program (a .exe). Stand alone usually refers to a single executable that can be run by itself.

Larger programs like Word, require many different files to run.

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