Volume Grafting
Volume grafting is a mechanism introduced in macOS 13 that mounts a disk image’s APFS contents as a subdirectory of an existing volume. This is...
Read more : Volume GraftingJoe T. Sylve, Ph.D. – Blog
Series
APFS Internals
A 27-part deep dive into the Apple File System covering on-disk structures, B-Trees, encryption, and more.
View the series : APFS InternalsPosts (Page 1 of 4)
Encryption Rolling
In our posts on Keybags, Wrapped Keys, and Decryption, we covered the static encryption architecture of APFS: how keys are...
Clonegroups
In our post on Data Streams, we discussed how APFS implements file cloning through shared extents and reference counting. While...
Transparent Compression (DECMPFS)
APFS supports transparent file compression through the DECMPFS (Decompression File System) framework, shared with HFS+. Compressed files appear normal to...
Hard Links and Siblings
In our post on Inode and Directory Records, we noted that a single inode may be referenced by more than...
EFI Jumpstart
APFS containers include an embedded EFI driver that allows UEFI firmware to boot from APFS partitions without requiring a built-in...
SpiceCrypt 3.0: QSPICE Support
SpiceCrypt 3.0.0 is out. When I introduced SpiceCrypt in March, it decrypted PSpice and LTspice model files so engineers could...
The Reaper
In our post on Containers, we introduced the Reaper as the subsystem responsible for garbage collection in APFS. The Reaper...
Space Manager
In our earlier post on Containers, we introduced the Space Manager as the subsystem responsible for tracking which blocks are...
Revisiting the APFS Series
Back in 2022 I started the APFS Advent Challenge: a daily run of posts dissecting the on-disk internals of Apple’s...