Welcome to the Datalight White Paper Library

The following papers are available for download. Where noted, some papers require registration for access.

FlashFX Pro and Flash Memory Related Papers

Using Embedded Linux and Flash Memory to Build Responsive and Reliable Products: 7 Best Practices Every Developer Should Know (and the three trends behind them)

Published: [24 January 2008]
Audience: Business ; technical
Overview: There are three key trends driving new embedded designs. Individually, each one is making a positive contribution to the embedded market, but in combination these trends may be leading to a data reliability nightmare.
This paper describes the convergence of these trends: growth in adoption of Linux for embedded designs, flash memory usage, and the importance of data, and how they represent a triple-threat to embedded devices. Included is a list of 7 best practices for software designers concerned about the success of their products.
Embedded Linux and Flash Memory

Why is Wear-Leveling So Important?

Published: [6 December 2007]
Audience: Technical
Overview: How long does the lifespan of your device need to be? Six months? A year? Ten years? If your file system doesn’t monitor the high-use areas of your flash and move frequent file writes to lower-use areas, the life of your flash could be shortened dramatically. This paper provides an overview of how wear leveling technology works and gives real-world examples of expected lifespan for specific use cases

Flash Wear Leveling [06 Dec 2007]

Choosing NAND or NOR Flash Memory: Tradeoffs and Strategies

Published: [16 November 2005]
Audience: Technical
Overview: Consumer electronics and embedded software devices are using larger amounts of flash memory for nonvolatile storage than ever before. So what kind of flash memory should you use? The choice between using NAND and NOR Flash may not be a simple one for the complex embedded devices being developed today. While ever-larger media files are driving increased demand for inexpensive NAND, powerful new operating systems and intricate applications running on fast processors ask for the fast-executing code NOR can support.

Choosing NAND or NOR: Tradeoffs and Strategies [16 Nov 2005]

Data is the New Design Problem

Published: [12 September 2007]
Audience: Business
Overview: Data integrity has replaced performance as the top design consideration for device manufacturers. As the data carried by devices grows in both quantity and importance, the industry has been forced to take a step back and deal with reliability issues. This paper explores the shift in data criticality for devices and examines what is being done to balance the competing requirements of performance and data integrity.

Data is the New Design Problem [12 Sept 2007]

Data Storage Media Considerations: Flash vs. Mechanical

Published: [26 July 2006]
Audience: Business ; Technical
Overview: There are a number of variables to consider when weighing the data storage advantages and disadvantages of non-volatile flash memory and mechanical hard disk drives. Although the differences are sometimes obvious, it is the vast disparity between the two and the stable similarities bridging them together that keep this battle interesting. Hardware manufacturers continue to mold new mediums that carry bits, while software experts overcome the limitations that keep each data storage media type from gaining market dominance.

Data Storage Media Considerations: Flash vs. Mechanical [17 Sept 2007]

Future of NAND Flash Memory

Published: [18 December 2005]
Overview: From MP3 players to picture phones to portable computer drives, millions of people now carry around devices capable of storing large amounts of data. It’s no wonder NAND flash memory has become the preferred nonvolatile data format for portable consumer electronic devices. Features such as high density, low cost, fast write times, and a long re-write life expectancy make NAND especially well suited for media applications in which large files of sequential data need to be loaded into memory quickly and repeatedly.

Factors Affecting Flash Memory Performance

Published: [21 February 2006]
Audience: Technical
Overview: The read, write and erase timing characteristics of flash hardware specifications are useful for comparing different products, but don’t tell the whole story about what you will get from your real-world devices. When Flash memory is incorporated into a system, the performance of the system depends on a number of factors. One key factor that can reduce the effective performance of flash memory involves the shared bus topology of your system. Optimal flash performance depends on the speed and availability of the bus that connects the flash to the system. Also critical are the manner in which the operating system handles interrupts and whether the flash device is connected to the system’s interrupt architecture.

Factors Affecting Flash Memory Performance [21 Feb 2006]

Overview of NAND Flash Memory Controllers

Published: [26 May 2006]
Audience: Technical
Overview: NAND Flash is a form of non-volatile memory introduced by Toshiba and Samsung in 1989. Its benefits include high storage density, fast access times, low power requirements and excellent shock resistance. MP3 players, high-end cell phones, and digital cameras are fueling expectations that NAND will overtake NOR in a number of markets. Integrating NAND into a system design presents key technical challenges. To simplify system designs, many processors are now including NAND controllers. This paper is an overview of this important technology.

Overview of NAND Flash Memory Controllers [27 Aug 2007]

NAND and NOR Convergence

Published: [29 January 2007]
Audience: Business ; Technical
Overview: NAND and NOR technologies each have distinct advantages for developers. Furthermore, there is a growing trend toward designing systems using both NAND and NOR arrays. New technologies such as Samsung OneNAND™ and Spansion OrNAND™ seek to offer the benefits of NOR and NAND within a single solution, while integrated NAND controllers simplify system design. This paper will examine NAND and NOR flash technologies, their advantages and disadvantages, then look at how these technologies are converging.

NAND and NOR Convergence [29 Jan 2007]

Managing Resident Flash Memory

Published: [16 February 2006]
Audience: Technical
Overview: This paper outlines how a flash memory management solution can increase data integrity and device reliability. Flash memory provides non-volatile, reliable, low power, low cost, and high-density storage for devices. Although flash memory has numerous characteristics that make it ideal for embedded applications, it also has features that require special attention.

Technology Comparison: SLC and MLC Flash

Published: [18 January 2007]
Audience: Technical
Overview: It is possible to double the capacity of flash memory within the same die by allowing multiple charges per cell. Increasing capacity in this manner has trade offs that need to be known by developers. This paper is an introduction into Single Level Cell (SLC) and Multi Level Cell (MLC) flash technologies highlighting the basic functions and benefits of each.

Leveraging Processor-supplied SRAM to Facilitate OneNAND Bootloaders

Published: [31 May 2006]
Audience: Technical
Overview: NAND flash memory densities for device-resident memory are increasing - and the price decreasing - with designers desiring to remove NOR flash devices from their design, and instead boot their processors from less expensive NAND. Due to the architecture of NAND flash memory devices, NAND flash cannot be used to boot processors unless the processor or the system contains some additional enabling logic. In the case of Samsung OneNAND™, this logic resides within the OneNAND part itself. Common OneNAND parts, such as the KFG1G16Q2A, supply a 1KB BootRAM buffer that automatically load from the internal NAND array at power on.

Leveraging Processor SRAM for OneNAND bootloaders [31 May 2006]

Reliance and File System Related Papers

File System Considerations in a Multi-Core RTOS Environment

Published: [18 January 2007]
Audience: Technical
Overview: Multi-core processing is rapidly becoming a necessity in embedded computing as demand for high density storage and a smaller footprint drives manufacturers to turn to MLC NAND in droves. With multi-core configurations consisting of dual core CPUs that share all local board resources, embedded single board computers are able to offset performance hits, meanwhile an extra CPU is supplied without duplicating any peripheral hardware. Since Flash memory is available with large storage capacity, using Flash to store a file system has become increasingly popular with embedded software to log large amounts of data or store complete sets of maps.

File System Considerations in a Multicore RTOS Environment [18 Jan 2007]

Fault Tolerance in a FAT File System

Published: [31 January 2006]
Audience: Business; Technical
Overview: Because of its large installed base, the FAT file system is sometimes considered a de-facto file system standard. This makes the FAT file system attractive for portable applications that need to exchange information with PC systems. However, the FAT file system was not designed to meet requirements of embedded systems such as reliability, data structure overhead and expandability. Probably the most significant shortcoming of the FAT file system is its lack of fault tolerance.

Fault Tolerance in a FAT File System [31 Jan 2006]

Journaling vs. Transactional File Systems

Published: [01 October 2007]
Audience: Technical
Overview: As end-user expectations rise and embedded devices get more complex, reliable file management will become more of a commonplace requirement. The file systems available in most embedded operating systems were not specifically designed with the needs of the embedded marketplace in mind, but instead evolved out of solutions developed for desktop and server environments. These file systems have significant shortcomings in embedded devices as they were not designed for use in an environment where power loss may occur. This white paper looks at the limitations of file systems in embedded devices, and then reviews two different solutions—journaling and transactional file systems— and the key differences between them.

Journaling vs. Transactional File Systems [01 Oct 2007]

Overview of Reliance Concepts, Metadata, and Operations

Published: [17 May 2005]
Audience: Technical
Overview: Data requirements for embedded systems today have grown exponentially over the last several years, and managing that data has been handled with the same file systems as used on desktop computers. Desktop file systems are not designed to take into account the harsh environments, power instability, or unattended continual use of embedded systems. Data loss on these systems causes either reduced functionality or complete loss in functionality for the embedded device. Datalight’s Reliance file system is designed to provide the high performance to enable a reliable and robust embedded device. This paper provides an overview of the general concepts and meta data used in the Reliance file system.

Overview Reliance Concepts Meta Data and Operation[17 May 2005]

Head to Head Reliance vs. TFAT

Published: [31 January 2006]
Audience: Business; Technical
Overview: For applications requiring fault tolerance there are currently two options available for Windows CE: Microsoft TFAT and Datalight Reliance. Datalight Reliance was designed from the ground up, to ensure data recovery in the event of power loss. TFAT however, must be modified to add additional transaction functions, such as the ability to transact on file write operations.

Performance Comparison: Reliance and VxWorks dosFs

Published: [8 June 2005]
Audience: Business; Technical
Overview: This paper characterizes the performance of the Datalight Reliance file system and the Wind River VxWorks 6.0 dosFs file system with and without a transactional layer. Each file system used the VxWorks 6.0 ATA block device driver interfacing to a Western Digital 40 GB hard drive in a 1.8 Ghz Pentium Celeron system. The performance tests consist of both sequential and random I/O, as well as a comparison of boot times.

Optimizing Reliance Performance Cache

Published: [27 August 2007]
Audience: Business; Technical
Overview: Reliance includes its own internal logical block cache. Generally, the larger the cache size, the better file system performance. However, since the cache uses system memory, setting an unnecessarily large cache size may be detrimental to overall system performance. Since performance tuning depends largely on application behavior, Reliance ensures design flexibility with its configuration sizes which can be adjusted to meeting specific application needs.

Optimizing Reliance Performance - Cache Config [21 dec 2006]

Reliance Return on Investment Analysis Guide

Published: [05 Oct 2007]
Audience: Business
Overview: Datalight Reliance can solve two problems facing embedded manufacturers today. First, Reliance can reduce warranty expenses associated with product field failure and returns. Secondly, Reliance can increase customer satisfaction by eliminating the end-user experience of losing data. This Guide enables embedded device manufacturers to analyze their potential return on investment from purchasing Datalight Reliance.

Reliance Return on Investment Analysis Guide [05 Oct 2007]

Transactional File System Performance Characteristics: Reliance and dosFs

Published: [8 June 2005]
Audience: Technical
Overview: This white paper explains the characteristics of two reliable “fail safe” file system options for VxWorks; Datalight Reliance™ and Wind River VxWorks 6.x dosFs. The key finding is both Reliance and dosFs with a transactional layer offer a fail safe file system. However, Datalight Reliance, in most cases, offers higher performance then dosFs with transactional layer.
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