BeagleBone Black and an abrupt loss of power

Hi All,

I’m considering using a Beagle Bone Black for a project that I am working on. I have some basic experience working with a couple of different microcontrollers/computers but I really like the specs of the Beagle Bone Black. I love that it can run various Linux distributions and the hardware profile matches my project requirements pretty closely.

One concern that I have is regarding the Beagle Bone Black’s ability to tolerate a sudden loss of power. On many embedded Linux systems, if power is lost abruptly, the file system can become corrupt, and the device will not be able to boot, unless the file system is completely rebuilt.

Can the Beagle Bone Black tolerate an abrupt loss of power and not be bricked? Ideally, for my project, the device would be powered down properly, but I can think of instances where the board might lose power suddenly. I was wondering if I would have to worry about having the device get bricked if this happened.

Thanks in advance!
Tomaso

Hi All,

I'm considering using a Beagle Bone Black for a project that I am working on. I have some basic experience working with a couple of different microcontrollers/computers but I really like the specs of the Beagle Bone Black. I love that it can run various Linux distributions and the hardware profile matches my project requirements pretty closely.

One concern that I have is regarding the Beagle Bone Black's ability to tolerate a sudden loss of power. On many embedded Linux systems, if power is lost abruptly, the file system can become corrupt, and the device will not be able to boot, unless the file system is completely rebuilt.

With rotating media, journaling file systems such as ext3/4 handle sudden asynchronous power losses fine. The problem seems to be that flash sub systems such as SSD/eMMC contain internal controllers which handle wear leveling/bad-block management etc. Here the issue becomes worse as the file system has no knowledge of these internal processes. I have worked with native flash file systems such as UBIFS, but they also suffer from phenomena such as "unstable-bits" http://www.linux-mtd.infradead.org/doc/ubifs.html#L_unstable_bits.

For these reasons, I am in the process developing a cape which provides short term battery backup and intelligence to perform an orderly shutdown. Other features include an independent watchdog and POE supprt.

Can the Beagle Bone Black tolerate an abrupt loss of power and not be bricked? Ideally, for my project, the device would be powered down properly, but I can think of instances where the board might lose power suddenly. I was wondering if I would have to worry about having the device get bricked if this happened.

The BBB would not be "bricked", but any file systems on the eMMC/SD may be corrupted.

Thanks in advance!
Tomaso

HTH,

Dave.

Thanks Dave for your post. It was very helpful, especially the link to the unstable-bits article.

I have a follow-up question, if power is lost abruptly, does the unstable bits simply result in lost data, or does the file system become corrupted and could previously stored data get damaged? Or does are the results unpredictable?

I think I might have to build a shield or external circuit as you are considering doing, to provide continuous power to the unit in spite of fluctuations in the external power supply.

Thanks again for your help!

Tomaso

In my limited experience, the results are unpredictable. There was a commercial flash file system a few years ago (I think the name was FlashFX) but I could not get good answers as their system was “proprietary”.