YAFFS Debugging
YAFFS provides a debugging mechanism which can be controlled at runtime, or set at build time. This page descirbes the options available and how to use them, for when you need to do some troubleshooting.
YAFFS: the NAND-specific flash file system - Introductory Article
YAFFS stands for "yet another flash file system"(*). As far as I am aware, YAFFS is the only file system, under any operating system, that has been designed specifically for use with NAND flash. YAFFS is thus designed to work within the constraints of, and exploit the features of, NAND flash to maximise performance. YAFFS uses journaling, error correction and verification techniques tuned to the way NAND typically fails, to enhance robustness. The result is a file system that exploits low-cost NAND chips and is both fast and robust. YAFFS is highly portable and runs under Linux, ucLinux and Windows CE. YAFFS is an open source project.
Inner Space
Outside the Earth's atmosphere lie many kinds of radiation, some harmful to humans and some harmful to Silicon chips. Chips used in space have to treated carefully lest Cosmic Rays alter the states of the atoms in the chips. In digital electronics very small errors can have very grave consequences, so reliable storage of data is especially important.
“Almost 15 years …never seen a failure...”
The DDS range of digital data storage solutions from Tape Replacement Ltd deliver a modern, solid state data storage unit designed specifically to replace out-dated magnetic tape, magneto optical, disc hard-drive units such as those used within legacy telephone switching systems. This saves companies such as telcos, and ultimately their customers, millions of dollars in upgrade costs as well as improving overall system reliability and keeping functioning equipment from being dumped in landfills.
Yaffs in space!
NASA TESS Mission This Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky.
It is a project regularly using our Yaffs File System to store incoming data and preserve it, in the rigours of the space environment, before sending it back to Earth.
Yaffs for VxWorks
The purpose of this document is to describe the Yaffs-on-VxWorks wrapper and provide sufficient information to port Yaffs to the VxWorks BSP. It assumes a working knowledge of VxWorks.
It does not describe the inner workings of Yaffs, and study of other Yaffs documents is recommended. Documents shown below in Italics will be found at http://yaffs.net/documents . . .
The source and the definitive version of this document can be found in our git repository, together with other Yaffs documents.
Considerations in Choosing a Flash File System
Failures in an embedded File System in a product are much more serious to the user than failures in an office computer. Power failures and failures to cache data properly can be avoided by choosing a FFS specifically designed for reliability from the ground up.
Yaffs NAND flash failure mitigation
NAND flash is one of very few types of electronic device which are knowingly shipped with errors and are expected to generate further errors without causing system failure. This document describes the most important failure modes and how they may be addressed in software.
Running Yaffs Direct Tests
This provides a outline to the various tests that are incorporated into Yaffs Direct. Most of these tests were written as debug tools to test error response by various Yaffs functions. These and others can be used to check if Yaffs is working properly.
Yaffs Direct Interface
This describes the Yaffs Direct Interface (YDI), which allows Yaffs to be simply integrated with embedded systems, with or without an RTOS.