What is a Windows service?

Winndows service is a program that can be started with the Windows operating system. It runs in the background and generally does not interact with users. It cannot be run by double-clicking, similar to the Unix daemon processes. It will not stop when the user logs out.

Windows Services are composed of three parts: 1. A service executable file; 2. one Service Control Program (SCP); 3. the Service Control Manager (SCM) is responsible for creating service key values under HKLM "system" CurrentControlSet "services. You can use SCP to control the startup, stop, and suspension of a service. SCP calls the service program through SCM.

Window standard EXE executable programs usually have a user interface, console or GUI, which is usually started or stopped by users.

3. What is the maximum memory size that a single process can access on windows?
Windows uses a virtual addressing system. The system maps the available memory addresses of the program to the actual addresses in the hardware memory. These tasks are fully managed in the Windows background, the actual result is that each process on a 32-bit processor can use 4 GB of memory-no matter how much hard disk space on the computer (this value will be larger on a 64-bit processor ). This 4 GB memory actually contains all the parts of the program ------ including executable code, all the DLL loaded by the code, and the program
The content of all variables used during running. This 4 GB memory is called virtual address space or virtual memory.