Tuxera Reliance Edge™ is the only embedded file system designed to capture and preserve decision-quality data with deterministic behavior required by today’s autonomous systems. A transactional file system, Reliance Edge protects critical system and user data from corruption, especially for systems where power loss may occur. When paired with a flash translation layer flash driver like FlashFX Tera, Reliance Edge delivers the functionality of a complete flash file system.

Why choose Tuxera Reliance Edge


Protect critical data

Reliance Edge is a copy-on-write transactional file system, meaning live data is never overwritten. This makes the system extremely power fail-safe. True transactional architecture ensures complete metadata and file data integrity. Dynamic Transaction Point™ technology gives developers complete compile-time and run-time control.

Uncompromising performance

Our software provides substantially faster overall performance compared to alternatives. Tuxera’s general-purpose file system I/O testing showed Reliance Edge to have a significantly higher performance in all read tests, as well as nearly all write tests. Our FSIOTest measures a variety of file I/O types, working with virtually any file system, and is included with Reliance Edge.

Ultimate control with determinism

Our configuration options allow developers complete control over which features are included, providing ultimate customizability – allowing our file system to fit your specific use case just the way you need it. Regardless of how it’s configured, its key file system operations are deterministic, providing unprecedented predictability.

Small footprint fits anywhere

Our file system is small and portable, ideal for resource-constrained embedded systems like microcontrollers. It can be configured to use as little as 4 KB of RAM, and has only 12 KB of code.

Fast mount time

After power loss or a system crash, the system must recover rapidly to keep the data stream flowing. In these so-called "dirty" situations, no need to rely on replaying a journal or performing any other file system checks. Reliance Edge ensures your decision-quality data is safe, while mount times are lightning fast.

Award winning support

Tuxera’s team of file system experts will support you all the way from evaluation to implementation, going above and beyond to ensure your project performs flawlessly and on schedule. Our annual support subscriptions for Reliance Edge are available with a choice of service level options, so you can select the right degree of support that suits your needs.

Watch our demo on
power fail-safety for Reliance Edge

Technical data and resources

Transactional design

Never overwrites live data. Once data is written, it’s always in a determinate state.

Tree-based metadata

Mounts quickly and consistently after unexpected shutdown/power loss.

MISRA C:2012 compliant

Source code ships compliant. MISRA C:2012 Design Assurance Package available to commercial licensees.

Small footprint

Ideal for resource-constrained environments. Configurable to use as little as 4 KB of RAM with 12 KB of code.

Supported block device drivers

Works with a broad array of storage media including: HDD, eMMC, SD/MMC, NVRAM, USB mass storage, and SATA (or PATA) disks.

Atomic writes

Metadata never points to wrong user data.


Reliance Edge Developer's Guide



One small step to a reliable file system


Flexible configuration options

Tuxera Reliance Edge has three main options for file system configuration. Each thread-safe option is also completely power fail-safe, preserving file system structure and user data in the case of a power interruption. Flexible transaction point configuration is available for each option. Key file system operations are deterministic, providing unprecedented predictability.

  • API set
  • Number of files
  • Number of volumes
  • Maximum stack depth
  • Buffers (minimum)
  • File references
  • Code size (ROM)
  • RAM requirement


Includes path-based file access, file handles, and atomic directory operations (including rename).

  • POSIX-like
  • Variable
  • Multiple
  • 824
  • 12
  • Names
  • 17.6 KB
  • 8.4 KB


Contains the same POSIX-like APIs Full, but excludes rename.

  • POSIX-like (not including rename)
  • Variable
  • Multiple
  • 744
  • 6
  • Names
  • 16.7 KB
  • 5.3 KB


Supports read, write and truncate on files referred to by a number, which is configured at compile time.

  • Constrained
  • Fixed
  • Multiple
  • 556
  • 5
  • Numbers
  • 10.6 KB
  • 3.9 KB

When to use Tuxera Reliance Edge

With a small footprint and rock-solid power fail-safety, Reliance Edge is the ideal choice when you need to manage and store mission-critical data, without straining CPU and memory usage of microcontrollers, small IoT devices, handhelds, and data-critical embedded systems used in automotive and avionics.

Automotive embedded systems

Mobile and handheld devices

Industrial applications

Aerospace and Defense

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Medical appliances

Networking and telecommunications

Available ports for Tuxera Reliance Edge


Reliance Edge is an official FreeRTOS component that brings best-in-class fail safety to real-time operating systems across industries.


Reliance Edge for INTEGRITY provides the highest levels of performance and reliability in industries that require certification – automotive, aerospace, defense, industrial, and medical.

ARM Mbed

Keep the RAM and CPU requirements of your IoT projects to a minimum using Reliance Edge for ARM Mbed, specifically engineered to support ARM Cortex-M microcontrollers.


Add full reliability to NXP processors running MQX, thanks to Reliance Edge transactional behavior that’s configurable at runtime.

Other RTOS

Reliance Edge is provided in full source code and can be ported to many RTOS environments. Connect our porting kit to an OS layer and a block device to deliver a fail-safe file system.


Works in harmony with SAFERTOS® to protect and preserve data in real-time and safety-critical applications.


Protect data from unexpected loss due to power failure or other system interruption, with our Reliance Edge port for Micrium µC/OS.

Power-failsafe file system for resource-constrained systems

Get Tuxera Reliance Edge

For software evaluations, pricing quotes, and more inquiries on Tuxera Reliance Edge file system, get in touch with us.

Pricing and evaluations

FAT is a trademark of Microsoft. SD is a trademark of SD Association. Green Hills and INTEGRITY are registered trademarks of Green Hills Software. FreeRTOS is a trademark of Amazon Web Services, Inc. Micrium is a registered trademark of Micrium, a subsidiary of Silicon Labs. MicroC/OS is currently maintained by Micrium, Inc. ARM and Mbed are trademarks or registered trademarks of Arm Limited (or its subsidiaries) in the US and/or elsewhere. Freescale and MQX are trademarks of Freescale Semiconductor, Inc.