John Siracusa and Dan Benjamin talk more about file systems: the origins of Btrfs, how file systems might change in the new age of SSDs, the possibility of a Grand Unification of storage and memory subsystems, and why snapshots, clones, block-level diffs, and deduplication are awesome features of ZFS that would make Time Machine a lot better than it is today. The show ends with John's predictions for the new iPad, which we all assume will be announced at the Apple press event next week.