CurrentControlSet\Services Subkey Entries

The Services subkeys under the following registry path contain parameters
for the device drivers, file system drivers, and Win32 service drivers:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

The name of each Services subkey is the name of the service, which is also
the root of the name of the file from which the service is loaded. For
example, for the serial mouse, the service name and Services subkey name is
Sermouse. The file from which this is loaded is:

SystemRoot\SYSTEM32\DRIVERS\SERMOUSE.SYS.

All service names are defined under:

     HKEY_LOCAL_MACHINE\SOFTWARE.

The names of the Windows NT built-in network services such as the Alerter
and Browser services are defined under the Microsoft\Windows
NT\CurrentVersion subkey in the Software area of the Registry.

Each Services key can have additional subkeys. Many services have a Linkage
subkey, which provides data for binding network components, as described in
"Linkage Subkey Entries for Network Components," in the article "Network
Adapter Cards Entries, PART 1." Many services also have a Parameters subkey
that contains entries defined by the service with values for configuring
the specific service.

Values for Parameters subkeys and other service-specific entries are
described in these articles:

Network Adapter Cards Entries
Device Drivers Entries
Network Services Entries

The following standard value entries appear for each Services subkey:

ErrorControl     REG_DWORD     Error constant
Specifies the level of error control for the service as follows:

Error Control  Meaning
Level

0x3 (Critical) Fail the attempted system startup.
               If the startup is not using the
               LastKnownGood control set, switch to
               LastKnownGood. If the startup attempt
               is using LastKnownGood, run a bug-check
               routine.

0x2 (Severe)   If the startup is not using the
               LastKnownGood control set, switch to
               LastKnownGood. If the startup attempt
               is using LastKnownGood, continue on
               in case of error.

0x1 (Normal)   If the driver fails to load or initialize,
               startup should proceed, but display a
               warning.

0x0 (Ignore)   If the driver fails to load or initialize,
               start up proceeds. No warning is displayed.

Group     REG_SZ     Group name
Specifies the name of the group of which the particular service is a
member.
Default: (null)

DependOnGroup     REG_MULTI_SZ     Group name
Specifies zero or more group names. If one or more groups is listed, at
least one service from the named group must be loaded before this service
is loaded.
Default: (empty)

DependOnService     REG_MULTI_SZ     Service name
Specifies zero or more Services subkey names. If a service is listed here,
that named service must be loaded before this service is loaded.
Default: (empty)

ImagePath     REG_DWORD     Path and filename
Specifies a path name. For adapters, this value is ignored.
Default: For a driver:

     systemroot\SYSTEM32\DRIVERS\driverName.SYS

For a service:

     systemroot\SYSTEM32\serviceName.EXE

(where driverName or serviceName is the same as the related Services subkey
name)

ObjectName     REG_DWORD     Object name
Specifies an object name. If Type specifies a WIN32 Service, this name is
the account name that the service will use to log on when the service runs.
If Type specifies a Kernel driver or file system driver, this name is the
Windows NT driver object name that the I/O Manager uses to load the device
driver.
Default: subkeyName

Start     REG_DWORD     Start constant
Specifies the starting values for the service as follows:

START TYPE     LOADER     MEANING

0x0            Kernel     Represents a part of the
(Boot)                    driver stack for the boot
                          (startup) volume and must
                          therefore be loaded by the
                          Boot Loader.

0x1            I/O        Represents a driver to be loaded
(System)       subsystem  at Kernel initialization.

0x2            Service    To be loaded or started
(Auto load)    Control    automatically for all startups,
               Manager    regardless of service type.

0x3            Service    Available, regardless of type,
(Load on       Control    but will not be started until
demand)        Manager    the user starts it (for example,
                          by using the Devices icon in
                          Control Panel).

0x4            Service    NOT TO BE STARTED UNDER ANY
(disabled)     Control    CONDITIONS.
               Manager

The Start value is ignored for adapters. If Type is a Win32 Service value
(as described below), the Start value must specify an Auto, Demand, or
Disabled value.

Tag     REG_DWORD
Specifies a load order within a given group. The value of Tag specifies a
number that is unique within the group of which the service is a member.
The related GroupName entry under the Control\GroupOrderList subkey
specifies a list of tags, in load order.

For example, the following services that are members of the Primary Disk
group could have these values: Tag=4 for the Abiosdsk subkey, Tag=2 for
Atdisk, Tag=1 for Cpqarray, and Tag=3 for Floppy. The value for Primary
Disk under the GroupOrderList subkey will use these Tag values to specify
the defined order for loading these services. As another example, each SCSI
miniport service has a unique Tag value that is used as an identifier in
the SCSI miniport value under the GroupOrderList subkey to define which
SCSI adapter to load first.

Type     REG_DWORD     Type constant

Specifies the type of service as follows:

Service Type   Description

0x1            A Kernel device driver.

0x2            File system driver, which is also
               a Kernel device driver.

0x4            A set of arguments for an adapter.

0x10           A Win32 program that can be started
               by the Service Controller and that
               obeys the service control protocol.
               This type of Win32 service runs in
               a process by itself.

0x20           A Win32 service that can share a process
               with other Win32 services.


For example, when you start Windows NT, the Boot Loader scans the Registry
for drivers with a Start value of 0 (which indicates that these drivers
should be loaded but not initialized before the Kernel) and a Type value of
0x1 (which indicates a Kernel device driver such as a hard disk or other
low-level hardware device driver). The drivers are then loaded into memory
in the order specified as the List value in
CurrentControlSet\Control\ServiceGroupOrder.