Datasheet: Reliance Edge

Tiny, power fail-safe filesystem for IoT edge devices

Tuxera Reliance™ Edge is the only file system designed to capture and preserve decision-quality data with deterministic
behavior required by today’s autonomous systems. Reliance Edge is a transactional file system that protects critical system
and user data from corruption, specifically for systems where power loss may occur. Tuxera’s unique file system works with abroad array of storage media including: e•MMC , SD/MMC, NVRAM, USB mass storage, and SATA disks and has been portedto many RTOSs, including FreeRTOS, SafeRTOS, μC/OS, ARM mbed, and MQX, as well as INTEGRITY, eMCOS, and AWS.
Reliance Edge continues the legacy of file system products in the Reliance family that have shipped in hundreds of millions ofdevices and is supported by Tuxera’s award-winning support organization.
Reliance Edge can be configured to meet the specific needs of your application by reducing complexity, optimizing resourceuse, 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 options that are easy to understand. Datastorage experts at Tuxera can help you make the most of them. Our POSIX-like API option makes integration straightforward
and Reliance Edge has the configuration flexibility to fit into even the tiniest of systems.

FEATURESCONFIGURATION OPTIONS
Full POSIX

Small POSIX

FSEssentials

Metadata fail-safety•••

File data fail-safety•••

Never overwrites live data•••

Transaction controls•••

Metadata CRC•••API setPOSIX-like

POSIX-like *Constrained

Number of files

Variable

Variable

Fixed

Number of volumes

Multiple

Multiple

Multiple

Maximum stack depth

824744556

Buffers (minimum)

1265Thread-safe•••

File referencesNames

Names

Numbers

Code size (ROM)17.6 KB

16.7 KB

10.6 KB

RAM requirement

8.4 KB

5.3 KB

3.9 KB* not including rename

1 |Datasheet: Reliance Edge

Ultimate control with determinism

PACKAGE COMPARISON

Reliance Edge configuration options allow developers

Itemcomplete control over which features are included, allowing

Source code

you to make the file system fit your specific use case precisely

Utilities

as you need it. Regardless of how it’s configured, Reliance
Edge’s key file system operations are deterministic, providing
unprecedented predictability.

Open-source package

Commercial package••

Configuration utility••

Formatter•••

Checker••

Full POSIX Configuration:

Image builder

This configuration includes a full POSIX-like file system API,

Image copier

including path-based file access, file handles, directory

Tests

operations (including atomic rename), transactions, and file

Disk full tests•system formatter. Configuration options with support for up

API tests

to ten tasks, ten open file handles, 512‑byte block size, and•fs stress test

twelve buffers (the minimum for this configuration) were used

Small POSIX Configuration:

Detailed comments•

Reference manual

available•••

ReadmeA reduced RAM option is illustrated by the Small POSIX
remaining POSIX-like APIs. The number of buffers used in•Documentation

to determine code size and RAM requirement.

configuration, which excludes rename but includes all•1•
1

Can be downloaded for no charge from Tuxera website

this configuration was reduced to the new minimum of six,

Better reliability for a better user experience

which reduces the RAM requirement. Configuration options

Device reliability means different things to different people.

were otherwise the same as the Full POSIX configuration.

Lack of reliability can have consequences ranging from a

FSEssentials Configuration:

failed mission due to lost or corrupted data, warranty returns
due to program corruption, or a frustrating user experience

This configuration includes the full FSE API, which supports– the enemy of customer loyalty. Because Reliance Edge isread, write and truncate on numbered files, as well asa copy-on-write transactional file system, live data is nevertransactions. Configuration options of 512‑byte block size

overwritten. This makes the system extremely fault tolerant

and twelve buffers (the minimum for this configuration) wereeven after an unexpected system shutdown caused by power

used to determine code size and RAM requirement.

loss or component failure. True transactional architecture

Fast, consistent mount times

designed into Reliance Edge ensures rock-solid datareliability as Reliance Edge maintains complete metadata andIn cases where power failure may occur, Reliance Edge has

file data integrity, while providing the performance neededa definite mount time advantage. There is no need to replay

to create an optimal user experience. Dynamic Transaction

a journal or perform any other file system checks—Reliance

Point™ technology gives developers complete compile-timeEdge always keeps the disk in a known good state.

and run-time control.

REQUIREMENTS
Target configuration

Typically a 32-bit microcontroller; with or without an RTOS; as little as 4 KB RAM (config. dependent)

Development system

Linux or Windows host; 40 MB of disk space for Reliance Edge

Supported media

e.MMC, SD/MMC, CF cards, RAM, NVRAM, USB Mass Storage, or HDD

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

2 |Datasheet: Reliance Edge

Our Software Test team uses multiple tools to verify basic

Write performance

functionality via API tests, along with reliability via power
fail simulation. Designed for maximum portability, Relianceusing various implementations of GCC, including Atmel
Studio 6.2.

Random2000
KB / second

Edge is also tested on FreeRTOS and Microsoft Windows

Sequential

2500

1500
1000
500

Uncompromising performance

0Raw

Reliance Edge has strong read and write performance,compared to FatFs and FAT SL on FreeRTOS. What is evenmore impressive is that this comparative advantage exists
even though Reliance Edge is preventing data loss frompower interruption while the native file systems are not.

with a Sitara AM3358BZCZ100 ARM Cortex-A8 processor, using a 16GB SanDisk class-10 microSD
card as the storage media on a 2GB partition.

Read performance

I/O test (FSIOTest), which measures a variety of file I/O types

6000
KB / second

7000

included with Reliance Edge.

3000
2000

block size since reading and writing in chunks of this size0

advantage offered by Reliance Edge is particularly
meaningful when the write sizes are smaller than the blocksize.

Raw

Reliance Edge - unified

with a Sitara AM3358BZCZ100 ARM Cortex-A8 processor, using a 16GB SanDisk class-10 microSD
card as the storage media on a 2GB partition.

Faster writes

Reliance Edge was configured to transact on fsync, file close,Reliance Edge

FAT entries to improve performance. FAT SL does not havethat option, and overall performance suffered as a result.

FatFS

FAT SL2
MB / second“fast seek” feature was enabled, which caches many of theReliance Edge - client-server

Figure 2. These performance numbers for all of these tests were gathered on a BeagleBone Black

2.5

disk full and volume dismount. For the Fat Fs file system, theRandom

4000

1000

in IoT devices, I/O sizes are often small, so the performance

Sequential

5000

Each file system was configured to use a 4096 byte
provides the best performance. In the real world, especially

Reliance Edge - client-server

Figure 1. These performance numbers for all of these tests were gathered on a BeagleBone BlackThe test used here was Tuxera’s general purpose file system
and works with virtually any file system. Tuxera FSIOTest is

Reliance Edge - unified

1.5
10.5
0512

1024

2048

4096

Integrity checking guards against data
corruption due to media failure

Figure 3. These performance numbers for all of these tests were gathered on a BeagleBone Black

Advanced instrumentation enables fast, precise diagnosis

card as the storage media on a 2GB partition.

of errors within the storage subsystem. Finding thewith a Sitara AM3358BZCZ100 ARM Cortex-A8 processor, using a 16GB SanDisk class-10 microSD

consuming part of the development process, which canSmart transaction model guarantees
integrity

delay market availability for many weeks. At the heart ofThe design of Reliance Edge provides both system and data

Tuxera’s file system diagnostics are full metadata CRCs

integrity with or without atomic sector writes. Most modern(Cyclic Redundancy Checks), which enable developers tomedia support this feature, which guarantees the sector

continuously monitor reliability in any embedded system.

being written will contain either completely written new data

Unlike basic file systems such as FAT, Reliance Edge isor the original values. Reliance Edge provides stronger error

capable of monitoring metadata to detect and provide early

checks at mount time if atomic sector writes are available. In

warning of imminent media failure and data inconsistencies.

cases where this feature is not available, data integrity is also

source of these storage media failures is normally a time-3 |Datasheet: Reliance Edge

guaranteed thanks to proprietary transaction technology.

Discards

Software integration and licensing

In the commercially-licensed version, discards provide

Tuxera provides Integration and Optimization Services

significant performance benefits and create less flash wear,

to create a custom binary module tuned for your project.

which extends flash lifetime. This is achieved by enabling theAffordable runtime distribution licensing can be structured

disk to perform compactions more efficiently. File systems

to fit your project budget. Commercially-licensed projects

using the flash memory driver, FlashFX Tera, experience even

include a comprehensive Developer’s Guide, API reference,

greater performance improvements, making it the perfectand validation utilities.

complement to Reliance Edge.

Open-source licensing

Simple architecture enables faster
implementation

A version of Reliance Edge is available as an open-source

The Reliance Edge RTOS services API is designed to be

be used, modified, evaluated, and distributed without

easy to implement for any RTOS, even a simple scheduler

charge, provided the user adheres to v2 of the GNU

loop.

documentation

General Public License (GPL) and does not remove theprovides a searchable reference to every library function

copyright notice. Please note that certain Reliance Edgeand configuration, leaving the developer free to concentrate

features are only available in the commercially-licensed

on a superior application for the customers. It is far quicker

version. See comparison chart on page 2.

Ourcomprehensive

developer

to utilize the fully tested Reliance Edge file system than towrite a custom data storage that is both power fail safe andwell tested.

project for evaluation and personal use. That version may

Commercial licensing
Businesses and individuals that, for commercial or otherreasons cannot comply with the terms of the GPL v2 license,

Data exchangeability

must obtain a commercial license before incorporating

If the media used with Reliance Edge is removable, such asa USB drive or a SD card, data on that media can be copied

Reliance Edge for distribution in any form.

to and from a Windows-based computer using the Reliance

Professional technical support

Edge Image Copier/Image Builder command line utilities.

Tuxera’s award-winning technical support has a strong

A FUSE version of Reliance Edge is also available on Linux.

commitment to making your devices work reliably, fromtesting to implementation. Tuxera regularly goes above andbeyond to make sure your project performs flawlessly.
Annual support subscriptions are available with a choiceof service level options that provide reliable access to
responsive Tuxera file system experts ensuring your project
stays on schedule.

Let us ensure your embedded storage remains responsive and stable.
Get in touch with us at sales@tuxera.com

Tuxera Inc. Global HQ
Westendintie 102160 EspooFinland
www.tuxera.com

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