Fundamentally simple: a preserved copy of a volume at a moment in time. How its size can only increase with time, how they’re managed, what they’re used for, and the tools for using them.
APFS
It makes a big difference whether an app, file or folder is in the System or Data volume, or maybe somewhere else. Here’s how to tell accurately, rather than according to one of the Finder’s illusions.
How to read a UUID to determine whether it’s supposed to be random, or has a specific meaning. Where you’ll find them, and whether you’ll ever see two the same.
Add another volume to your Mac’s internal SSD and try to eject it. All hell breaks loose as the Finder wants to eject the whole disk, it seems. Probably a 6-year old bug.
A survey of support for APFS, HFS+, FAT and ExFAT, NTFS, ZFS, Linux file systems, and MacFUSE with its potential for file systems running in user-space.
Trim enables an SSD to erase pages of unused memory so they’re ready for reuse. It saves time, and greatly improves write performance. How to the best out of Trim.
Study how the four key timestamps of a file change when you create, edit, preview the file, using Dropera.
Two confounding factors to take into account when interpreting timestamps on files: what updates the Last opened time, and access via QuickLook.
First Aid in Disk Utility, or fsck_apfs in Terminal, have given warnings or errors with id numbers. How do you work out which file or folder that refers to?
First Aid in Disk Utility, or running fsck_apfs in Terminal, return warnings or errors on one of your Mac’s volumes. Here’s what to do next.
The Eclectic Light Company 