Reliability on Windows CE 6.0
Watch Rob Hart demonstrating the Datalight flash file system on the Beagle Board with Windows CE 6.0
Posts Tagged ‘flash file system’
Reliance Nitro Makes an Impact
Last week one of our customers sent the following evaluation report in an email to Datalight support staff:
“Right now we are in the process of testing the impact of Reliance Nitro in our application. Apparently, we noticed some boost in the performance: faster write speed, significant speed increase of transaction point creation, faster read speed, and significantly faster directory read (we typically have 1000 files in the directory). So, in conclusion, the overall performance of the system is boosted quite significantly.”
Another real world example of how Reliance Nitro boosts performance in directories with a large number of files. To learn how Reliance Nitro does it, check out the whitepaper.
Reliance and Reliance Nitro
Ever since we announced our high performance file system Reliance Nitro, we have been getting questions on how it compares to the original Reliance file system. Below is a quick-reference table noting some of the differences between the two. For a more detailed comparison (including performance benchmarks), please contact us.
| Attributes | Reliance | Reliance Nitro | Recommendation |
| High performance on large number of files (100+) | √ | If your device stores a large number of files in a single directory, Nitro will perform much faster than Reliance. | |
| High performance on large files | √ | Nitro’s extent based design allows it to perform faster on larger files. For sake of this comparison, files can be considered large if they are 10+ times the block size of the device | |
| Frequent transaction points | √ | Nitro introduces a new structure called Delta transactions which speed up the time taken to conduct transaction points. Depending on how often you conduct transactions points, Nitro can provide significant advantage | |
| Random I/O performance most critical | √ | √ | Reliance’s block based design provides an advantage on random I/O on small files. On large files both Reliance and Nitro perform equally well on this metric |
| Sequential I/O performance most critical | √ | Nitro outperforms Reliance on sequential I/O due to its extent based design | |
| Support for Windows Mobile | √ | FlashFX Pro 4.0 for Windows Mobile enables a new discard interface that allows Nitro to have much faster write speeds on flash memory | |
| File-size limit | 32-bit | 64-bit | Nitro uses 64-bit variables for file size limits allowing for very large file sizes. |
| Read-only version | √ | Reliance currently provides a read-only version called Reliance Reader. Nitro currently does not provide a reader application – this is scheduled for v2 |
I HEART Reliance Nitro
With the release of our new file system this week, Reliance Nitro, we asked our Account Managers what they liked most about our new product. Their answers of course included reliability and high performance. Wes Johns and Phillip Allison were so excited they decided to make a video… watch the youtube video
Reliance Nitro Demo Video
We’re totally psyched about Reliance Nitro, our newest file system (yes, we’re file geeks), and we’re always on the lookout for opportunities to show off the performance and reliability attributes it adds to Windows Mobile and Windows CE. When we discovered the relatively-new Beagle Board, it occurred to us that a small, low-cost platform might be just the thing to demonstrate Nitro’s amazing benefits. As you’ve probably heard, the Beagle is making waves with its low cost (around $150) and diminutive size. It uses an OMAP 3530 processor and 256MB of NAND. Though they are most commonly used with Linux, we lucked out in having a partner (MPC Data) who has already developed a Windows CE BSP for it. After a few phone calls, the wizards at MPC Data were able to develop a slick video playback demo app, and presto, the Reliance Nitro Beagle Demo was born! Amateur videographers that we are (ok, REALLY amateur), we recently videotaped John Burnham, who has been working on this project on the Datalight side (and who is a really good sport, btw) showing what happens when power is interrupted during a file write and the extra reliability factor of Reliance Nitro on Windows CE. Be sure to check it out here.
File System Tuning using Dynamic Transaction Point Technology
Datalight Reliance includes unique technology called Dynamic Transaction Point ™ which provides the flexibility and control device manufacturers need to tune the performance of their device. It enables multiple configurations that can run simultaneously to provide scenario-specific performance optimization. To highlight this technology, we have added a section to Datalight’s website to describe some common embedded devices and the corresponding file system tuning attributes for each of them
Why Raw NAND Flash with Hardware-based ECC is the Way to Go
5 Reasons for Ditching Managed NAND
Everyone knows that NAND has challenges: from factory bad blocks and spontaneous bit failures to endurance limits, etc. That’s why a few years ago managed NAND (NAND flash plus an integrated controller) seemed to be the answer, offering the density of raw NAND, while mitigating many of its inherent limitations. What many device manufacturers may not realize is that the management hardware comes with significant costs, both in terms of dollars per part as well as design limitations. In the world of tradeoffs in which every system designer lives, there are solid technical reasons to consider using raw NAND and leaving the management to software instead. While there are clear commercial advantages for Datalight (as a provider of vendor-neutral software-based flash management) to advocate this approach, we also believe that there are strong technical reasons that flash silicon vendors would do well to embed ECC capabilities into their NAND flash devices rather than relying on ‘total hardware’ solutions such as eMMC or other complex and costly controllers. Beyond the benefits outline below, this approach would allow the flash manufacturers the ability to continue to differentiate their products from others in the industry.
1. Cost
The cost of managed NAND parts is coming down, but the stuff still sells at a premium over its raw NAND brethren.
2. Flash Optimization
There are many new features of NAND available to us today. Performance features such as cached reads, multi-plane operations, concurrency, and others are becoming invaluable to keep performance at the ever-increasing demands of portable media. The Open NAND Flash Interface (ONFI) has defined a standard method to query the capabilities and characteristics of NAND flash which can be put to use by both software and hardware systems. A software media manager offers the flexibility to take advantage of the most current flash memory features and put them to use efficiently, or to avoid certain features that may be unproven or problematic. A software solution will allow a developer to take full advantage of the media’s characteristics and features unburdened by the indirection or inability for the hardware to expose them.
3. Visibility/Flexibility
Software (in general) is easily inspected and validated. Features such as wear-leveling move data around the flash device to optimize its life expectancy. Without the ability to inspect source code, a managed NAND solution makes it difficult to validate wear-leveling operation and/or characterize its effect on performance and reliability. Hardware implementations are often generalized to suit a majority of use cases, while a software solution is easily tailored to the specific use case during development.
4. Performance
Speaking of use cases, there are many system features that are not available to hardware that may make a generalized hardware solution less advantageous to a specific use case. For example, system idle time can be used to improve the media performance by scheduling background cache operations and compaction to occur then. Coordination between the file system and flash media manager can further optimize operations by freeing space when it will no longer be needed and having the media manager code cache certain regions of the flash where meta data might be held. Migrating flash management features to hardware removes this ability to coordinate with other components of the software stack, such as file systems.
5. Reliability
Lest you think we believe that everything is better left to software, consider error detection and correction (EDC). Error rates are increasing substantially as flash manufacturers push the limits of physics. Errors can be introduced externally by heat or other radiation, during writes or reads of data, and even to data that was successfully written at a different time. Historically SLC NAND flash required only a single bit error detection and correction (a hamming code is usually sufficient), while MLC parts require minimally four bit EDC. As the die sizes continue to shrink, error rates will continue to increase, even for SLC flash.
Calculating the codes to detect and correct such errors is getting increasingly complex and solving such a solution in software for higher-bit EDCs (above 4-bit) is time consuming and often unacceptably slow. Hardware ECC is a necessary requirement for systems with high EDC requirements and where performance is a concern.
Many of the processors on the market today are incorporating EDC in their NAND controllers. Choosing one of these processors (e.g. TI OMAP 35xx) in combination with raw NAND flash and software management can give you the high-performance EDC to handle next generation flash while maintaining the design flexibility that a software manager provides.
Flash manufacturers have much to gain by adding ECC code into their NAND flash parts. They know better than anyone what kind of ECC is necessary for a specific part and by adding just that one piece of hardware to their offerings, rather than the jack of all trades, master of none approach of complete flash management, they will better serve the markets.
In short, features should reside where they can be handled most efficiently; ECCs belong in hardware, other flash management functions belong in software. While managed NAND certainly has its place and its appeal in the market, we believe the best combination of value, performance and flexibility lies in using a combination of raw NAND and hardware with built-in ECC capabilities.
Migrating from mDOC: Options, Challenges and Benefits
SanDisk recently announced that it is end-of-lifing several flash parts in the mDOC family and OEMs who were using these parts in their devices are now looking at viable alternatives. In order to help these affected customers make informed decision, we have published a new whitepaper on options for migrating from Sandisk mDOC flash family.
The paper is available at http://www.datalight.com/mdocwhitepaper/
Reliance Transactional File system demo
Demonstrating how system software work in a visual manner is an interesting problem, especially in embedded space. There is no UI or visual effects to WOW the audience. To evaluate the value system software components bring to an embedded design, the customer usually needs to configure our software on his embedded development board. This provides for comprehensive evaluation but can be a significant effort. . We run into this very often at Datalight since our primary products (FlashFX Pro and Reliance) are system level embedded software. One way we have attempted to demonstrate our software is to make a full-functional version of our software run on user’s desktop PC. This allows the customer to run the software without any special hardware in matter of minutes and understand the core working of our software. Once they believe there is value, the can request source code access and try it on the actual embedded hardware.
The first demonstration that we have built is for Datalight Reliance. This demo is available to all users who are registered for MyDatalight account. The video below shows how you can use this software on any Windows PC and understand how Reliance unique transactional design allows for 100% reliability against data corruption and how Dynamic Transaction Point technology allows developers to tune their file system even while the device is running.
Datalight Flash File System Boosts Performance for Devices Built with MontaVista Linux
Bothell, Wash., – August 12, 2008 – Datalight announced today that it has released new versions of Reliance™ and FlashFX® Pro, with pre-configured support for MontaVista® Linux®. The new install experience includes simplified integration within MontaVista DevRocket, an Eclipse-based IDE that streamlines common embedded development tasks. Dropped into DevRocket, Datalight products build as kernel loadable modules that work with a project’s OS image. Sample bootstrap code is also supplied for developers who need to integrate the products into a boot loader.
“Developers choose MontaVista Linux for faster time-to-market, integration, and stable, fully tested code. We are pleased that Datalight has extended these benefits at the flash memory file system level, and to provide embedded Linux developers with added performance and reliability,” said Dan Cauchy, Senior Director of Market Development, MontaVista Software.
Other upgrades include a read-only version of Reliance inside the Datalight Loader. This small footprint version permits a bootloader to load an OS image directly from a reliance partition. Devices benefit from risk-free “in-place OS upgrades” enabled by the application-controlled transaction point feature of Reliance. The new versions also feature enhancements in reliability, as well as support for a wide range of new flash parts. FlashFX Pro now supports Spansion NS-P, Samsung FlexOneNAND, Micron 55nm flash parts, and all CFI-compliant NOR parts. The Datalight flash file system solution is comprised of the Reliance file system and FlashFX Pro intelligent flash media manager. Reliance was designed from the ground up for high reliability applications. Dynamic Transaction Point™ technology provides 100% immunity from file corruption, even after unexpected system interruption. Embedded applications can benefit from faster boot times that remain consistent for the life of the product, regardless of disk size.
FlashFX Pro features pre-written support for over 200 flash parts, works with virtually any NAND controller, and features wear leveling, bad block management, and garbage compaction for unrivaled performance. Datalight flash file system products are also available on other operating systems and integrated development environments.