Can someone explain to me the new Apple partitioning?

[MacBH928]

I know there is a disk then that disk can be partitioned into other "partitions" . In the new APFS system I am completely confused I am not sure what is going on. There is Volume, partition, disk, and container? Can any one clear the confusion here what is going on?

I made a bootable copy of Catalina using Super Duper software. I got 2 partitions, one called Macintosh HD and the other is Macintosh HD-Data. What is the "data" one ? Also I do not see a recovery partition? How do I get it back?

 

[sgtaylor5]

With Catalina, the APFS container has been split into two APFS volumes: System and Data. To you, the System is Read Only and Data is Read/Write. They appear as one volume to the user, due to a new kind of symbolic link called a firmlink. This feature is macOS specific.

With Big Sur, Monterey and above, the System Read Only volume has been cryptographically signed and locked, then an APFS snapshot of that System volume is mounted, and that's what you see when you boot.

The only way to see which applications are where is to use the Terminal.

This is where my Books application is (came with the OS): "/System/Applications/Books.app" ; can't be touched at all.
This is where my Corona app is (I installed it): "/Applications/Corona.app" ; this can be manipulated by me. But, because of a firmlink, the Applications folder (one each on two different volumes) looks like one folder to the user.

The Recovery partition isn't visible by the user in any way, not even by Disk Utility.

 

[MacBH928]

With Catalina, the APFS container has been split into two APFS volumes: System and Data. To you, the System is Read Only and Data is Read/Write. They appear as one volume to the user, due to a new kind of symbolic link called a firmlink. This feature is macOS specific.

With Big Sur, Monterey and above, the System Read Only volume has been cryptographically signed and locked, then an APFS snapshot of that System volume is mounted, and that's what you see when you boot.

The only way to see which applications are where is to use the Terminal.

This is where my Books application is (came with the OS): "/System/Applications/Books.app" ; can't be touched at all.
This is where my Corona app is (I installed it): "/Applications/Corona.app" ; this can be manipulated by me. But, because of a firmlink, the Applications folder (one each on two different volumes) looks like one folder to the user.

The Recovery partition isn't visible by the user in any way, not even by Disk Utility.

great explaination, thanks 👏🏼

So the container is like a partition now and inside it are 2 volumes. So if I can't write to the system volume, who gets to write to it?

 

[sgtaylor5]

great explaination, thanks 👏🏼

So the container is like a partition now and inside it are 2 volumes. So if I can't write to the system volume, who gets to write to it?

only Apple can write to the System Volume, and then only with an OS Installer app.

 

[KALLT]

So the container is like a partition now and inside it are 2 volumes.

You could consider an APFS container a “partition” on a system with a single disk (i.e. hardware store, such as SSD or HDD). However, an APFS container can in fact consist of multiple partitions across separate disks, e.g. the Fusion disks that Apple had (SSD and HDD combined into one APFS container). APFS container and partition are therefore not strictly synonymous.

Within an APFS-formatted partition, you are usually working within a single APFS container that consists of volumes. On an Intel Mac, the APFS container of the boot disk (as of Catalina at least) comprises five volumes: Macintosh HD, Macintosh HD – Data (these two are furthermore combined into a "volume group", which is what binds them together), Preboot, Recovery and VM. You won’t see the latter three volumes in Disk Utility, but you can see them with diskutil:

diskutil list