Why XProtect Remediator scans can report BadPluginServiceSignature status_code 31 and abort, and why you don’t need to do anything about it.
CTS
What can you do when your Time Machine backups stop running regularly? Or another background activity has gone missing?
While macOS uses DAS-CTS to schedule hundreds of background activities, third-parties normally use launchd. Comes with a full diagram explaining DAS-CTS.
How running a background task takes a tiny fraction of second, although the task itself takes seconds or minutes, and why it’s run on E cores.
How macOS schedules tasks like making automatic Time Machine backups, from property list to transactions between DAS and CTS.
The story of how Mac OS X went from cron, to launchd, and ended up with Duet Activity Scheduler, to schedule background activities like backups.
Although there doesn’t appear to be any straightforward way to run command tools or scripts only on Efficiency cores, there are ways and means.
Prior to 10.4, Mac OS X used cron, then scheduling became part of the job of launchd. Later Apple added a new subsystem, Duet Activity Scheduler, which continues to evolve.
How the start of Time Machine backups to APFS volumes is scheduled and dispatched, and a fascinating Secure Backup Daemon.
How Time Machine has changed since it appeared in 2007, and how backing up to APFS volumes is different now it’s available in Big Sur.
The Eclectic Light Company 