Start Values

There is a Start value for each Services subkey in the Registry key HKEY_LOCAL_MACHINE\SYSTEM\<control set>\Services\DriverName. It specifies the starting values for the device or service, as follows:

• 0x0 (Boot) = Loaded by boot loader (NTLDR or OSLOADER) before the Kernel is initialized. Disk device drivers are examples of device drivers that use this value.

• 0x1 (System) = Loaded by the I/O subsystem during Kernel initialization. The mouse device driver is an example of a device driver that uses this value.

• 0x2 (Auto load) = Loaded by Service Control Manager. To be loaded or started automatically for all startups, regardless of service type. The parallel port device driver is an example of a device driver with a value of auto load. The Alerter service is one of the services that uses this value.

• 0x3 (Load on demand) = Loaded by Service Control Manager only when explicitly instructed to do so. Available, regardless of type, but it is not be started until the user starts it (for example, by using the Devices option in Control Panel).

• 0x4 (Disabled) = Do not load. Windows NT sets device drivers to disabled when Service Control Manager should not load them, such as when the corresponding hardware is not installed. Having this value means that the device drivers are not loaded by Service Control Manager. File system drivers are the one exception to the Start value. They are loaded even if they have a start value of 4. If a device driver is accidentally disabled, reset this value by using the Services option in Control Panel.

Note

You can view the Start value of device drivers by using the Devices option in Control Panel.