Sparse files are now common among databases, disk images, and virtual machines. How they work in APFS, how they’re created, and how they can explode.
HFS+
Classic TM backed up HFS+ to HFS+; current TM backs up APFS to APFS. But what if you want to back up a mixture of APFS and HFS+ volumes?
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.
From the GPT division of storage space, through APFS containers, down to individual volumes, an account of how APFS works.
Introduced in iOS 10.3 on 27 March 2017, then in macOS 10.13 six months later. It ups and downs, and where it still has further to go.
B+trees, directory records, directory and file names and Unicode normalisation, and whatever happened to the promise of fast directory sizing?
First released 16 years ago, it was destined for Time Capsules, and relied on hard links in HFS+. It soon used APFS snapshots, and now uses them as the basis for its backups.
Disk errors threaten your data: how to detect them, how to use First Aid in Disk Utility, how to use fsck, and what to do with the disk afterward.
Where to look for file metadata in the Finder, and how you can customise it, in spite of its apparent confusion. And how APFS takes care of extended attributes for you.
How does copy on write work, and how do clones grow apart? What effect do they have on the use of space and performance?
The Eclectic Light Company 