µC/OS RTOS and Stacks

Transactional File System

File system for decision-quality data at the edge of the IoT

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What is Datalight Reliance Edge?


Datalight Reliance Edge™ is a transactional file system that protects critical system and user data from corruption specifically for systems where power loss may occur.

This module is available for purchase separately from µC/OS.


Reliable RTOS Embedded File System

Reliance Edge is a file system offering for Micrium customers who do not need FAT compatibility. It is the only file system designed to capture and preserve decision-quality data with deterministic behavior required by today’s autonomous systems.

Reliance Edge can be configured to meet the specific needs of your application by reducing complexity, optimizing resource use, and maximizing performance. Whether your application requires a single log file, a pre-defined set of files with fixed names, or complete flexibility to modify file hierarchy during runtime, Reliance Edge has easy to understand options. Datalight’s POSIX-like API option makes integration straightforward and Reliance Edge has the configuration flexibility to fit into even the tiniest of systems.

This module is available for purchase separately.


  • Offers data protection from unexpected loss due to power failure or other system interruption when FAT compatibility is not required
  • Ideal for resource-constrained environments; can be configured to use as little as 4 KB of RAM, 12 KB of code
  • True transactional architecture ensures rock-solid meta and user data reliability; live data is never overwritten
  • Atomic transaction model protects both user data and meta data from corruption
  • Fast, consistent mount times; disks always in known good state
  • Pre-ported to μC/OS RTOS
  • Monitors metadata to detect inconsistencies and provide early warning of imminent media failure and data inconsistencies
  • Ships as source code that is MISRA C:2012 compliant; MISRA C:2012 Design Assurance Package available to commercial licensees
  • Open-source version available for evaluation and personal use
  • Commercial-use license for those who cannot comply with GPL v2 restrictions or require warranty and support guarantees


Target Configuration Typically a 16- or 32-bit microcontroller; with or without an RTOS; as little as 4 KB RAM (config. dependent).
Development System Windows host; 40 MB of disk space for Reliance Edge.
Supported Media eMMC, NAND, NOR, SD/MMC, RAM.
RAM Required 4 KB to 19 KB (depending on configuration).
Maximum Volume Size 7.3 GB at 512 byte block size to 256 TB (terabytes) at 64 KB block size.
Max File Name Length Configurable at compile time, typically between 6 and 40 bytes in length.
Path Name Length No fixed limit. Individual name length defined at compile time.

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