Demand Start Driver

This topic provides a procedure that you can use to configure how a non-Plug and Play device driver is started when you start your computer.

Setting the Start Type Value

You should set display drivers that are written to the Windows Display Driver Model WDDM to start to run on demand on Windows Vista and later, rather than during.

What Determines When a Driver Is Loaded Hardware Dev Center. Search File system filter drivers commonly use this start type or SERVICE_DEMAND_START.

I have a demand-start driver installed and want to start/stop it as needed from the user-mode application that uses it. sc start myservice works just fine for the.

How to temporarily deactivate the kernel mode filter driver in Windows Email Print ; Support for SCM must start the driver or service on demand.

To start and stop non-Plug and Play drivers Open Device Manager Click the View menu, and then click Show hidden devices. Double-click Non-Plug and Play Drivers.

Trucking slowed down at the start of The demand for commercial truck drivers is expected to grow by 21 from the Georgia Department of Driver.

What Determines When a Driver Is Loaded

The default start is start demand. boot. A device driver that is loaded by the boot loader. sc query type driver sc query type service sc query state all.

Kernel Driver: Running: Demand Start: system32 DRIVERS vwifimp.sys: Virtual WiFi Miniport Driver / Microsoft Windows Operating System: Microsoft Corporation.

Before exploring when and how file system drivers are loaded during the system boot sequence, it is necessary to understand driver start types and load order groups.

A kernel-mode driver s start type specifies whether the driver is to be loaded during or after system startup. There are five possible start types:

Indicates a driver started by the operating system OS loader. File system filter drivers commonly use this start type or SERVICE_DEMAND_START. On Microsoft Windows XP and later systems, filters must use this start type in order to take advantage of the new file system filter load order groups.

SERVICE_SYSTEM_START 0x00000001

Indicates a driver started during OS initialization. This start type is used by the file system recognizer. Except for the file systems listed below under SERVICE_DISABLED, file systems including network file system components commonly use this start type or SERVICE_DEMAND_START. This start type is also used by device drivers for PnP devices that are enumerated during system initialization but not required to load the system.

Indicates a driver started by the Service Control Manager during system startup. Rarely used.

SERVICE_DEMAND_START 0x00000003

Indicates a driver started on demand, either by the PnP Manager for device drivers or by the Service Control Manager for file systems and file system filter drivers.

Indicates a driver that is not started by the OS loader, Service Control Manager, or PnP Manager. Used by file systems that are loaded by a file system recognizer except when they are the boot file system or in the case of EFS by another file system. Such file systems include CDFS, EFS, FastFat, NTFS, and UDFS. Also used to temporarily disable a driver during debugging.

A driver writer can specify the start type for a driver at installation time in either of the following ways:

By specifying the desired start type for the StartType entry in the service-install-section referred to by an AddService directive in the driver s INF file. This method is described in ServiceInstall Section.

By passing the desired start type for the dwStartType parameter when calling CreateService or ChangeServiceConfig from a user-mode installation program. This method is described in the reference entries for CreateService and ChangeServiceConfig in the Microsoft Windows SDK documentation.

Within the SERVICE_BOOT_START and SERVICE_SYSTEM_START start types, the relative order in which drivers are loaded is specified by each driver s load order group.

Drivers whose start type is SERVICE_BOOT_START are called boot or boot-start drivers. On Microsoft Windows 2000 and earlier systems, most filters that are boot drivers belong to the filter group. On Microsoft Windows XP and later systems, filters that are boot drivers generally belong to one of the new FSFilter load order groups. These load order groups are described in detail in Load Order Groups for File System Filter Drivers.

Driver whose start type is SERVICE_SYSTEM_START are also loaded in the order of the load order groups to which they belong. However, no system-start driver is loaded until after all boot drivers have been loaded.

Note   Load order groups are ignored for drivers whose start type is SERVICE_AUTO_START, SERVICE_DEMAND_START, or SERVICE_DISABLED.

A complete, ordered list of load order groups can be found under the ServiceGroupOrder subkey of the following registry key:

HKEY_LOCAL_MACHINE System CurrentControlSet Control

The same load group ordering is used for SERVICE_BOOT_START and SERVICE_SYSTEM_START drivers. However, all SERVICE_BOOT_START drivers are loaded and started before any SERVICE_SYSTEM_START drivers are loaded.

A driver writer can specify the load order group for a driver at installation time in either of the following ways:

By specifying the desired load order group for the LoadOrderGroup entry in the service-install-section referred to by an AddService directive in the driver s INF file. This method is described in ServiceInstall Section.

By passing the desired start type for the lpLoadOrderGroup parameter when calling CreateService or ChangeServiceConfig from a user-mode installation program. This method is described in the reference entries for CreateService and ChangeServiceConfig in the Microsoft Windows SDK documentation.

For more general information about driver load order and load order groups, see Specifying Driver Load Order.

Send comments about this topic to Microsoft.

You should set display drivers that are written to the Windows Display Driver Model WDDM to start to run on demand on Windows Vista and later, rather than during operating-system initialization, as was the case with display drivers that ran on operating systems prior to Windows Vista. This change is due to manifest and image-based-install functionality that was not present on operating systems prior to Windows Vista. You should set the value for the StartType entry to SERVICE_DEMAND_START 3 rather than SERVICE_SYSTEM_START 1.

The following example shows a service-install section with the value for the StartType entry set to SERVICE_DEMAND_START to indicate that the display miniport driver is started on demand:

; Service Installation Section

ServiceType 1 ; SERVICE_KERNEL_DRIVER

StartType 3 ; SERVICE_DEMAND_START

ErrorControl 0 ; SERVICE_ERROR_IGNORE

For more information about service-install sections that are associated with the AddService directive, see INF AddService Directive.

Send comments about this topic to Microsoft.