226: Smooth Scrolling Is For Suckers

Normalization

John Siracusa explains the intricacies of APFS filename normalization and its implications for users. He highlights the introduction of native normalization in macOS High Sierra, where filenames are stored as provided but directory lookups use hashes of normalized versions. This ensures that even if a program uses different encoding, it can still find the correct file.

APFS on high Sierra has native normalization. What that means is file names are stored as provided by the program in the file system.

--- John Siracusa

John also mentions future updates for iOS that will incorporate runtime normalization, allowing for seamless file access across devices 1 2.

   

Conversion Challenges

The transition from HFS to APFS presents significant challenges, particularly in handling file compression and user experience. John Siracusa notes that Apple's engineers were surprised by how many iOS programs directly pass user input to file system APIs without proper normalization, leading to potential file access issues.

It's going to cause them to have to change the file system on every single iOS device at some point in the future.

--- John Siracusa

Casey Liss adds that Apple conducted trial runs of the APFS migration to ensure a smooth transition, highlighting the complexity and scale of this engineering feat 3 4.