‘I have detailed Files’  (The ‘T800’ in Terminator II)

JesFs – Jo’s Embedded Serial File System V1.5

Definitely files will be on of the most important key topics in the upcoming IoT. Because files separate functionality and data.

Just think of very simple things like language data: on a “very small” Embedded Device (not something “big” like an Embedded Linux, but something that can run with small batteries for years): it is commonly integrated “somewhere in the code”. Difficult to change! But if the language data is in files, changes are easy. Same for graphics, setups, everything… It even allows to change the firmware on the Embedded Device from many different sources!

Think of Embedded Devices, that even can get their latest firmware by themselves! E.g. over WiFi, Mobile Internet, Bluetooth, … Suddenly all options are open! And if you have concerns about the security: don’t worry: problem already solved, as you’ll see later..

The main problem for “very small devices” – until now – was the “File System”: everybody knows “FAT”, “NTFS”, … but have you ever thought of a file system on a small chip? Or even inside of a CPU?

No problem, with the right Software. This is why I wrote “JesFs – Jo’s Embedded Serial File System“:

My daily work ist the IoT. Because I did not find any really practical solution, I decided to create my own one.

“Robustness”, “Security” and “Small Footprint” were my design constraints.

JesFs was designed for use in the “Real World”. For use with standard Serial NOR-Flash memories, like the M25R-Series, used on TI’s CC13xx/CC26xx Launchpads or the nRF52840-DK from Nordic and which is available up to 16 MB, or even more…

Some Basics about JesFs:

• Ultra-Small RAM and code footprint: can be used on the smallest MCUs with only 8kByte program memory or less (like the famous MSP430-series, almost all kind of 32-Bit ARM cores (M0, M3, M4, ….)). Only 200 Bytes of RAM are sufficient!
• Completely Open Source (GPL v3) and written in Standard C.
• Works with Serial NOR-Flash from 8kByte to 16MByte (opt. up to 2GByte), but could also be used with CPU-internal NOR-Flash.
• Works hand-in-hand with the Ultra-Small JesFsBoot Secure bootloader (requires less than 8kB on standard ARM cores, including an AES-128 encryption engine for reliable Over-the-Air-Updates (“OTA”)).
• Includes optimised Wear Leveling (for maximum life of the memory).
• Very Fast Data transfer (e.g. reading files: 3.7MB/sec on nRF52840).
• A special mode was added to allow millions of write cycles, especially for data collection, event reports and journaling aplications.
• JesFs is persistent: no data loss on power loss.
• Designed for (almost) all situations, where NOR memories could be used (the ones where only blocks can be deleted (0->1) and only 0 written.
• Strictly taylored to Ultra-Low-Power Embedded Systems.
• Designed to use the advantage of an underlying RTOS, but can also be used standalone.
• Sample applications for the nRF52840-DK, Launchpads CC13xx/26xx and others
• Well documented and easy to use with an intuitive API

Find the JesFs_Test-Application (C Source and Manual) on GitHub