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How to Configure a FAT File System

Other versions of this page are also available for the following:

Windows Mobile Not SupportedWindows Embedded CE Supported

8/28/2008

In the process of developing an OS design, you must provide file access and memory management for your design by configuring FAT file system support.

For Windows Embedded CE:

You can configure the FAT File System either alone, as an Extended FAT File System (exFAT) or as a Transaction-Safe Extended FAT File System (TexFAT).

If you choose to configure the FAT file system alone, it does not impact run-time image performance, but it has more limited capacity than an exFAT system. In addition, a FAT file system alone is not a transaction-safe file system such as TexFAT and can be corrupted if a write operation is interrupted.

To remedy this, you can configure a FAT file system as exFAT, or as exFAT with TexFAT to support the optional additional features of those systems. You can further customize your FAT, exFAT, or TexFAT file system by editing the file system settings in the Common.reg file for your OS design.**

For Windows Mobile:

Procedure

For Windows Embedded CE

Step Topic

1. Create an OS design.

Creating an OS Design with the Windows Embedded CE OS Design Wizard

2. Familiarize yourself with the benefits of FAT, exFAT, and TexFAT file systems, and choose one as your file system.

FAT File System

Extended FAT File System

Transaction-Safe Extended FAT File System

3. If you want to force FAT to always perform a write-through operation, regardless of the parameters sent to CreateFile, set the ForceWriteThrough registry value to 1 in the Common.reg file for your OS design.

FAT File System Registry Settings

4. If you want to enable disk caching, set the EnableCache value in the Common.reg file to 1.

In addition, choose an appropriate size for each cache.

FAT File System Registry Settings

5. If you want to use exFAT, set FormatExfat to 1 in Common.reg.

Extended FAT File System

6. If you have chosen to use TFAT and you want data to always be transacted, set TransactData to 1 in the Common.reg file.

Transacting data has a negative affect on performance

FAT File System Registry Settings

7. If you have chosen to use TFAT and are using a file system block driver that does not perform atomic write operations, set NonatomicSector to 1 in the Common.reg file.

FAT File System Registry Settings

8. Build your run-time image.

If your run-time image builds with no errors, you have successfully configured your FAT file system.

Building a Run-Time Image

See Also

Concepts

FAT File System
Transaction-Safe Extended FAT File System
FAT File System Registry Settings

Other Resources

Transaction-Safe FAT File System