In a move designed to eliminate potential data loss in file system applications, Micrium, a leading provider of high quality embedded software components, announced the addition of a critical journaling feature to the file allocation table (FAT) version of its uC/FS File System software. The new feature addresses a significant gap in FAT file systems data security, as it ensures that the FAT itself will be able to restart following a power failure. The addition of journaling builds on uC/FS’ strong failsafe capabilities for media drivers that were introduced earlier this year.
“Offering an embedded file system that renders FAT failsafe offers a tremendous level of reassurance to developers and consumers, as multimedia storage devices increasingly move to flash memory, and enlarge their on-board storage capacities,” said Jean Labrosse, president and CEO of Micrium. “FAT itself is not failsafe, so even in FAT file systems with fail-safe media drivers, there are cases when the file system can be corrupted. Journaling is the answer to this problem, and uC/FS is the only FAT-based embedded file system currently bringing this differentiating capability to the marketplace.”
Journaling is an extension to uC/FS that makes the file system layer failsafe, by ensuring that the file system logs all changes to a journal before committing them to the main file system. Since data can be lost in either the file system layer (FAT or EFS) or in the driver layer if, for example, an unexpected reset occurs, or write access is interrupted due to power failure, the entire system is failsafe only if both layers are failsafe. Adding journaling to the file system layer guarantees a file system that is always in a consistent state.
The journaling layer prevents corruption by caching every write access. All changes to the file system are stored in a journal, and the data stored in the journal is copied into the file system only if the file system layer operation has been finished without interruption. This procedure guarantees the consistency of the file system, because an interruption of the copy process will not lead to data loss as the interrupted copy process will be restarted after a restart of the target.
uC/FS’ FAT version supports the file system standard found on all PCs, allowing for data to be moved easily between embedded devices and the PC. uC/FS is provided as full source code and offers a low, one-time fee and no royalties on deployed products.
To learn more about uC/FS’ failsafe capabilities please visit Micrium at the Freescale Technology Forum, Pedestal 1113, June 16-19 in Orlando, Fla.
- Supports FAT and FAT-Free (EFS) file system structures
- Works with any RTOS, but does not require one
- FAT features include: long filenames, multiple volumes, media error handling, mix of media, check disk and multiple media drivers, journaling
- Flash drivers are failsafe and include multiple volumes, wear-leveling, directories, bad block management and ECC algorithms
- Media drivers include: NOR Flash Driver, NAND Flash Driver (including Atmel’s DataFlash Driver), Secure Digital Driver (including High Capacity SD), Compact Flash Driver and RAM Disk
- Available Windows simulation for development, including a Windows driver to allow use of the PC drives
Micrium provides high-quality embedded software components by way of engineer-friendly source code, unsurpassed documentation and customer support. The company’s world-renowned real-time operating system, uC/OS-II, features the highest-quality source code available for today’s embedded market. Micrium’s products consistently shorten time-to-market throughout all product development cycles.