File System Driver Registry Settings (Windows Embedded CE 6.0)

  • Article

1/6/2010

File system drivers (FSDs) can be loaded in two different ways. FSD can be auto-loaded by the file system on boot, or loaded in response in response to mounting a storage device that is discovered during startup or after media insertion.

When a file system is loaded, its configuration settings are found in the registry. To control how an FSD loads, set registry values according to your preferred means of loading.

  • Auto-loaded
    Auto-loaded FSDs are mounted during the boot sequence. Auto-load settings are located at HKEY_LOCAL_MACHINE\System\StorageManager\AutoLoad\<MyAutoLoadFSD>
    For more information, see Autoload Settings.
  • Loaded in response to mounting a storage device
    If an FSD is loaded in response to a storage device being mounted, the FSD loads in response to the type of the partition being mounted.
    Settings for partition type are located in the partition table definition at
    HKEY_LOCAL_MACHINE\System\StorageManager\PartitionTable
    For more information, see Partition Manager.

The following table shows the values you can set for an FSD.

Value Name Required? Description

Dll:REG_SZ

Yes

Provides the name of the FSD DLL to be loaded.

Util: REG_SZ

No

Describes the name of a utility/helper DLL that provides functions such as format, scan, and defrag for the file system.

Order:REG_DWORD

No

Specifies the order in which this FSD should be loaded, relative to other automatically loaded file systems in the same phase of startup. Lower order numbers cause the FSD to load earlier. If this value is not specified, the FSD loads last.

BootPhase:REG_DWORD

No

Specifies the phase of startup in which to load the driver. Possible values are 0, 1, and 2. If no phase is specified, the driver is loaded during phase 1.

An FSD loaded during phases 0 or 1 must also set the registry value LoadFlags to 1.

LoadFlags:REG_DWORD

No

Specifies whether the FSD should be loaded synchronously or asynchronously.

If set to 1, the FSD is loaded synchronously. If an FSD is loaded during phases 0 or 1, LoadFlags must also be set to 1 to load synchronously.

If set to 0, the FSD is loaded asynchronously.

Paging:REG_DWORD

No

Specifies whether the FSD supports demand paging for memory-mapped files. Paging is supported by default.

Additional file system–specific registry values are placed under this same key. These values can be read by the FSD using the FSDMGR_ registry helper functions.

Auto-Loaded File Systems

Auto-loaded file systems are unified file systems that do not use an underlying disk driver to read and write sectors. A good example of an auto-loaded file system is a network file system driver, which relies on network protocols to perform I/O, rather than using a disk. Another example might be a unified flash file system in which flash I/O routines are statically built into the FSD.

Registry value settings drive the installation of auto-loaded file systems during the boot sequence. The following example shows a typical auto-load registry key:

[HKEY_LOCAL_MACHINE\System\StorageManager\AutoLoad\MyAutoLoadFSD]
   "Dll"="MyAutoLoadFSD.DLL"
   "Util"="MyAutoLoadFSDUtility.DLL"
   "Order"=dword:0
   "BootPhase"=dword:1
   "LoadFlags"=dword:1
   "Paging"=dword:1

File Systems Loaded in Response to Mounting

If an FSD is loaded in response to to the fact that a storage device is mounted, the FSD actually loads in response to the type of the partition being mounted. The partition type is a single byte value that is specified when the partition is created.

The PartitionTable registry value under the StorageManager key specifies the mapping between a partition type and a file system. For more information, see Partition Manager.

See Also

Concepts

Installable File System Drivers
File Systems Registry Settings Overview
Storage Management