Remember HFS? How about HFS+? You can be forgiven if you don’t remember what HFS stands for. It’s Apple’s proprietary file system (HFS) and dates back to the last century. Get ready to say goodbye to HFS+ as it’s ready to be replaced with something from the future.
It serves as the primary file system of OS X. HFS+ was developed to replace the Hierarchical File System (HFS) as the primary file system used in Macintosh computers (or other systems running Mac OS). It is also one of the formats used by the iPod digital music player. HFS Plus is also referred to as Mac OS Extended (or, erroneously, “HFS Extended”), where its predecessor, HFS, is also referred to as Mac OS Standard (or, erroneously, as “HFS Standard”).
HFS+ has been around forever but has outlived itself by years. But changing file systems is no easy task but the time is now, or soon, so get ready for a replacement called Apple File System that likely will make its way to every device.
Apple didn’t mention it during the WWDC show but digging around in developer documents I found more details.
The Apple File System (APFS) is the next-generation file system designed to scale from an Apple Watch to a Mac Pro. APFS is optimized for Flash/SSD storage, and engineered with encryption as a primary feature. Learn about APFS benefits versus HFS+ and how to make sure your file system code is compatible.
In essence, APFS is the way Apple wants to manage files on current and future devices, which are more SSD flash drives than traditional hard disk drives. From the APFS Guide:
Space Sharing allows multiple file systems to share the same underlying free space on a physical volume. Unlike rigid partitioning schemes, which pre-allocate a fixed amount of space for each file system, APFS volumes can grow and shrink without volume repartitioning.
Each volume in an APFS container reports the same available disk space, which is equal to the total available disk space of the container. For example, for an APFS container with a capacity of 100GB that contains volume A, which uses 10GB, and volume B, which uses 20GB, the free space reported for both volumes A and B is 70GB (100GB – 10GB – 20GB).
That might be one of my favorite features in APFS. For now, resizing a volume using OS X requires some thought and consideration, but APFS makes that much easier to manage.
The Guide itself appears to be a work in progress as Apple says more details will be provided in a future developer’s release. I look forward to Snapshots which appears to be one of the number of features borrowed from Sun’s once promising ZFS.
The features of ZFS include protection against data corruption, support for high storage capacities, efficient data compression, integration of the concepts of filesystem and volume management, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, RAID-Z and native NFSv4 ACLs.
Remember Sun and ZFS?
Apple’s WWDC keynote events cover highlights that are beneficial to the developer community and device users, but scratch the surface a bit and you’ll find tidbits like Apple File System which point to the future.