Six MIT research boffins have demonstrated a system capable of recovering all data in the event of a crash that was previously constrained to high-end theory.

The team will October showcase the first albeit slow file system "mathematically guaranteed" to not lose data during crashes.

Authors Haogang Chen; Daniel Ziegler; Tej Chajed; Adam Chlipala; M. Frans Kaashoek, and Nickolai Zeldovich say the system lends itself to more efficient technology and could be applied to create more reliable file systems.

“What many people worry about is building these file systems to be reliable, both when they’re operating normally but also in the case of crashes, power failure, software bugs, hardware errors, what have you,” Zeldovich says in a statement.

“Making sure that the file system can recover from a crash at any point is tricky because there are so many different places that you could crash.

"You literally have to consider every instruction or every disk operation … and so empirically, people have found lots of bugs in file systems that have to do with crash recovery, and they keep finding them, even in very well tested file systems, because it’s just so hard to do.”

The researchers' achievement is in proving the file system's final code and not just schematics, a feat accomplished with a proof assistant tool.

The proofs are checked against the file system rather than "some whiteboard idealisation" that lacks formal connection to the code.

The team rewrote the system specifications about 10 times but spent the most energy on the definitions of and relations between system components.

“No one had done it,” Kaashoek says. “It’s not like you could look up a paper that says, ‘This is the way to do it.’ But now you can read our paper and presumably do it a lot faster.” ®