Rather than using cron or launchd, many background services in macOS are now run using Centralized Task Scheduling (CTS). This is how it works.
DAS
Adds a new log view of background task scheduling and dispatch, greatly improves volume info, and fixes a rare crash.
It’s not very often that we see the birth of a whole new subsystem both in macOS and iOS, but RunningBoard is brand new with 10.15 and 13.
When you find one, bugs will necessarily be multiple. If you think you’ve found one, you can be fairly confident that you’ll find more. Four bugs in macOS for the price of one.
macOS doesn’t handle significant errors and failures well, burying them away in the log. It needs to report them to the user through a new sub-system.
Oils were king until the 1960s, when acrylic paints became readily available. How do they differ from oils, though?
How does the ‘Optimize Storage’ feature work? Indeed, does it work? A look at its confusions and a couple of bugs.
When does macOS decide to download new and changed items in iCloud Drive? This steps through the process from decision to completion.
How does macOS learn of changes which have taken place in iCloud Drive, such as the uploading of files from another system? Here the process is taken apart, and points of failure highlighted.
When you upload a file to iCloud Drive, the steps involved are complex. They’re outlined and diagrammed here, with pointers to how to diagnose and resolve problems.
The Eclectic Light Company 