How the resource forks of Classic Mac OS became extended attributes in Mac OS X 10.4, then flourished. How clone files handle xattrs, and which are used by APFS itself.
APFS
If the Finder’s Get Info dialog may report inaccurate total file size, does that mean the folder sizes are also incorrect? And does this affect volumes too?
How to obtain and read entries in the Unified log made by APFS. Their structure, and a guide to their identification and occurrence.
Classic Mac OS could give the size of data and resource forks. High Sierra ignored extended attributes, and Sonoma tries to add them, but only includes some.
Union mounts let you merge the contents of two volumes without copying any files. Do they work as expected in Sonoma’s APFS, though?
Other file systems, with an outline of vfs and vnodes used by the kernel, and how they’re important in checking code signatures.
This reference covers fsck_apfs, diskutil information, diskutil apfs, conversion of HFS+ to APFS, mount_apfs, and newfs_apfs.
Overview of clone files, dataless files, sparse files, symbolic links, and firmlinks, and how used and free space is accounted for in APFS.
Keybags, wrapping keys, VEKs and KEKs all explained. Did you realise how Recovery Keys are implemented? Or how the SSV protects against read errors?
What’s in an APFS snapshot, and how the stages in its life-cycle work, from creation, through mounting and unmounting, to deletion and cleanup.
The Eclectic Light Company 