This is a great video that explains how flash memory works. Granted, the video is very technical but does work through the concept of reading and writing data to flash. So if you have the 17 minutes to use, I suggest giving this a watch. The video does cover SLC, MLC and TLC memory and how each of these technologies read and write with the different layers of a floating gate device like NAND.
As with any good project, there should always be a back up plan. The Curiosity for Mars is no different. The system has a B-Side computer in the event the A-Side computer went down…well guess what, it went down.
There is a theory that cosmic rays affected some of the flash memory on Curiosity causing the A-Side computer to shut down and reboot into Safe Mode.
JPL is currently backup up the A-Side data to the B-Side computer and should reboot by weeks end. Configuration and data transfer can take a while, then of course the verification process of everything done right.
“The hardware that we fly is radiation tolerant, but there’s a limit to how hardened it can be, you can still get high-energy particles that can cause the memory to be corrupted. It certainly is a possibility and that’s what we’re looking into.”
For updates please visit the NASA website.