Dark Arts of Data Storage: What's Your Filesystem up to?

Accepted Session
Long Form
Scheduled: Tuesday, June 26, 2012 from 10:00 – 11:45am in B201


Ever wonder what happens to your data between the write() call and the disk drive? Or feel the need to scrape your bits off the drive after an accident? If so, this talk is for you! Come learn the dark art of how filesystems work.


Have you ever wondered how your software stack saves data to durable media? Or how the computer organizes data on the disk so that it can retrieve data at a later date? Have you ever needed to pry your data off of a storage device after it has borked itself, but not known how?

If you can answer ‘yes’ to any of those questions, then you might appreciate this talk. Data storage is the most important side-effect of your digital life, and yet most people regard it as somehow magical.

Far from being magical, this talk will begin with a short history of the evolution of filesystem design, to explain how we got to where we are today. In the second half of the talk, I will dig into the low level structure of a couple of well-known open source filesystems by discussing how to interpret the artifacts recorded on disk, how to pull data off of a broken volume, and how the design decisions affect your application programs.

Speaking experience

I've spoken at numerous Linux conferences (OLS in 2006, Linux Plumbers Conference in 2008, 2009, and 2011), and given numerous presentations to attorneys and executives at my three-lettered employer. This is a new talk, though I've presented the subject material many times before.


  • Head


    Darrick has been cranking out patches to the Linux kernel for the past twelve years. In that time he has worked on many areas of the kernel, most notably ext4, storage drivers, energy management, firmware hacking, and environmental sensors. He is now attempting to bring about the future of data storage, whether that means adapting existing filesystems to new kinds of storage, making versioning cheap, or teaching the computer how to automatically repair damage.

    Before that, Darrick mostly wrote software toys (compilers, interpreters, even operating systems) for fun, and nosed around inside a computer more than he admits. He has yet to find a computer that he can’t crash.

    Off-line, Darrick enjoys dancing, exploring exotic back-country with a camera, and belting out songs.