Mike Bombich is the founder and president of Bombich Software, the developer of Carbon Copy Cloner. That’s a backup app for the Mac that has saved the day for many users. He’s a former Apple employee.

In this timely post-WWDC show, Mike joins me to explain the structure of APFS drives and the new read-only System files in macOS Catalina. He explained new features of volumes in macOS 10.15, especially how the System is isolated from the Data volume (which contains /Users). He also explained the new firmlinks that tie these two volumes together, making them appear as one. Finally, Mike explained how Carbon Copy Cloner external drives can no longer be HFS+ in Catalina but must become APFS.