Embedded Software Insight
In this article, we discuss 4 popular NOR file systems, commonly used in bare metal and RTOS-based embedded systems: LittleFS, Yaffs, FileX and TSFS. We provide a brief description of each file system and compare their performance, RAM consumption and other specific advantages and limitations. Of course, there are other file systems and storage solutions … Read more
This article discusses the performance limitations of the FAT file system with a focus on SD Card. After a brief refresher on FAT fundamentals, we show how FAT predictably achieves high access performances in the absence of fragmentation, but how fragmentation can build up until performances suddenly collapse. We conclude with a few important recommendations about the use of the FAT file system on embedded flash memory.
In this article, we explain how flash file systems achieve native support for raw flash devices. We compare flash file systems to a common alternative, which is the combination of a block device file system (e.g., FAT) with a flash translation layer (FTL), and we make the case that the native approach is a better overall solution.
In this article, we discuss the impact of real-time requirements on embedded file system performances and RAM usage. We show how to calculate the amount of buffering needed to absorb a hypothetical sequence of write accesses of varying duration. We show how RAM usage, write access time and average throughput are interdependent under our real-time assumption.
In this particular article, we show how the maximum average write throughput on a given flash device varies with the amount of stored data. We provide a simple performance model that can be used for setting realistic performance expectations, comparing file system performances, and questioning application requirements with minimal assumptions regarding the actual workload or file system implementation.
In this article, we cover five aspects of embedded file systems that you should have in mind when deciding which one to choose, five essentials that you can’t ignore. This is by no means a complete guide to embedded file systems but it covers enough to avoid common mistakes, particularly among application engineers who have little prior experience with embedded file systems.
QSPI NAND is a memory technology specifically designed as a direct alternative to its popular cousin, QSPI NOR. But what exactly is QSPI NAND? How does it compare to QSPI NOR? How does it compare to parallel NAND? This is what this article is all about.
In-depth comparison between NOR and NAND covering aspects of NOR and NAND flash technologies that, in our view, are too often ignored including the impact of the application requirements on the choice of Flash technology.
Let’s explore and compare two different paradigms of flash management commonly used throughout the industry: managed flash and unmanaged flash. Managed flash devices include SD cards, USB flash drives, eMMC and UFS modules — also SSDs, but those are less often seen in embedded systems. These are all NAND-based devices.
This article is the first of an introduction series about flash memory with a focus on embedded systems designs using an embedded file system. A high-level introduction shall we say. Not the kind that takes you straight to the electron and drags you through the depths of quantum physics. No. The purpose of this series … Read more