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Joe T. Sylve, Ph.D.

Digital Forensic Researcher and Educator

Joe T. Sylve, Ph.D. – Blog

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Clonegroups

In our post on Data Streams, we discussed how APFS implements file cloning through shared extents and reference counting. While j_phys_ext_val_t reference counts and j_dstream_id_val_t...

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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 Internals

Posts (Page 1 of 4)

Transparent Compression (DECMPFS)

APFS supports transparent file compression through the DECMPFS (Decompression File System) framework, shared with HFS+. Compressed files appear normal to...

APFS Internals · Part 17

Hard Links and Siblings

In our post on Inode and Directory Records, we noted that a single inode may be referenced by more than...

APFS Internals · Part 15

EFI Jumpstart

APFS containers include an embedded EFI driver that allows UEFI firmware to boot from APFS partitions without requiring a built-in...

APFS Internals · Part 11

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...

Security research

The Reaper

In our post on Containers, we introduced the Reaper as the subsystem responsible for garbage collection in APFS. The Reaper...

APFS Internals · Part 10

Space Manager

In our earlier post on Containers, we introduced the Space Manager as the subsystem responsible for tracking which blocks are...

APFS Internals · Part 9

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...

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