ServiceStartConstants

When and how the SCM starts a service. Assigned to ServiceManager.InstallStartMode at configuration time; the value is captured into the SCM database by ServiceManager.Install and can be changed afterwards through the Services control-panel applet or sc.exe config.

Constant	Value	Description
tbServiceStartBoot	0	Started by the boot loader at OS boot. Kernel drivers only — not applicable to twinBASIC services.
tbServiceStartDriverSystem	1	Started by Ntldr / Winload during system initialisation. Kernel drivers only.
tbServiceStartAuto	2	Automatically started by the SCM at system boot, before any user logs in. The typical setting for a background service that should always be running.
tbServiceStartOnDemand	3	Started by the SCM only when something explicitly requests it (control-panel applet, sc.exe start, Services.LaunchService, or a service that lists it in DependentServices). The default for new ServiceManager instances.
tbServiceStartDisabled	4	The service cannot be started until an administrator changes its start mode. Use this to deactivate a service without uninstalling it.

For user-mode twinBASIC services, the only three values that matter in practice are tbServiceStartAuto, tbServiceStartOnDemand, and tbServiceStartDisabled.