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Registry Settings for FATFS Disk Caching (Windows Embedded CE 6.0)

1/6/2010

Registry settings control disk cache behavior for file allocation table (FAT) file systems (FATFS).

You can place the following values at the following locations in the registry:

  • Root file system key
    Settings made at the root key of the file system registry, HKEY_LOCAL_MACHINE\System\StorageManager\FATFS, apply to every mounted instance of FATFS unless explicitly overridden by a setting at a lower level. These setting apply to FATFS for all profiles.
  • Profile-specific settings
    Settings made at the Profiles registry subkey, HKEY_LOCAL_MACHINE\System\StorageManager\Profile\<MyProfileName>\FATFS, apply only to devices that report the profile <MyProfileName>.

The following table shows the registry settings.

Registry value/type Applies to Description

BitmapCacheSize: REG_DWORD

Transaction-safe extended file allocation table (TexFAT)

Set to the size of the bitmap cache, in number of sectors.

If set to 0 (zero), FATFS determines the best cache size to use.

For more information, see CacheSize Registry Subkey.

CacheDLL: REG_SZ

FAT, TexFAT

Specifies the name of the disk cache library, such as diskcache.dll.

CacheSize: REG_DWORD

Obsolete

This value is obsolete.

Do not use in Windows CE 5.0 and Windows Embedded CE 6.0.

Replace with FatCacheSize or DataCacheSize.

Indicates the size of the disk cache, in number of sectors.

DataCacheSize: REG_DWORD

FAT, TexFAT

Indicates the size of the data cache, in number of sectors. If set to 0 (zero), FATFS determines the best cache size to use.

For more information, see CacheSize Registry Subkey.

EnableBitmapCacheWarm: REG_DWORD

TexFAT

Set to 1 to enable pre-warming of the bitmap cache.

EnableCache: REG_DWORD

FAT, TexFAT, extended FAT (exFAT)

Set to 1 to enable caching. Zero (0) disables caching.

EnableDataCacheWarm: REG_DWORD

FAT, TexFAT

Set to 1 to enable pre-warming of the data cache. That is, on initialization, the cache is pre-loaded to capacity with data.

EnableFatCacheWarm: REG_DWORD

FAT, TexFAT

Set to 1 to enable pre-warming of the FAT cache. That is, on initialization, the cache is pre-loaded to capacity with data.

EnableWriteBack: REG_DWORD

FAT, TexFAT

Set to 1 to enable a write-back cache. Set to zero to use a write-through cache.

This setting applies only to Windows CE 5.0 and later.

FatCacheSize: REG_DWORD

FAT, TexFAT

Set to the size of the FAT cache, in number of sectors.

If set to 0 (zero), FATFS determines the best cache size to use.

For more information, see CacheSize Registry Subkey.

LazyWriterThreadPrio256: REG_DWORD

FAT, TexFAT

Specifies the priority of the lazy write-back thread.

Note

When you enable pre-warming of the FAT or data cache, you trade longer startup times for quicker cache access when fully booted. To determine the settings that offer the best performance for your device, experiment with different values for EnableFatCacheWarm and EnableDataCacheWarm.

See Also

Reference

CacheSize Registry Subkey

Concepts

FAT File System Registry Settings
Disk Cache Management