Here are several good reasons that Big Sur will need more storage space than previous versions of macOS.
dual-boot
Are you an early adopter, or a cautious delayer? Here’s some advice about the forthcoming upgrade to Catalina to help you decide.
When you can’t install what the App Store offers: solutions for downloading and installing older versions of macOS for use with Catalina.
Want one external drive from which you can boot two (or more) different versions of macOS? Here’s how to make it.
Adding volumes in APFS is quick and simple. But why would you ever want to add a container to a disk? An exploration of their differences, and when containers are useful.
A post-mortem analysis on attempts to make my iMac dual-boot between Sierra and High Sierra. Can it be done in safety?
You might want to read these tips before installing the first release of High Sierra. They could save you a lot of pain.
The Eclectic Light Company 