как установить 2 mac os на 1 mac?

• Q: "how to install 2 Mac OS on 1 Mac"

• A: ?

An outline of how to use partitioned internal HDD or SSD for more than 1 macOS.

• How to dual-boot Mac: run two versions of macOS on a Mac | macworld.uk

https://www.macworld.co.uk/how-to/mac-software/dual-boot-mac-3659676/

Newer macOS systems, these have later APFS file systems; and include last

three or four versions of Mac operating system. High Sierra was first. And

this, about last macOS that can use HFS+ Extended or journaled partition.

Newer thinking turns away from time proven older methods though.

• Partition a physical disk in Disk Utility on Mac - Apple Support

https://support.apple.com/guide/disk-utility/partition-a-physical-disk-dskutl14027/mac

Partitioning a disk divides it into individual sections, each of which acts as a separate volume.

"..However, with APFS, you shouldn’t partition your disk in most cases. Instead, create multiple

APFS volumes within a single partition. ~ With the flexible space management provided by

APFS, you can even install another version of macOS on an APFS volume.."

These 10.13.6/10.14.6/10.15.6 and (beta) Big Sur 10.16/ macOS11.x benefit or need

newer Apple Partition (File System) Map. Several later macOS versions could

share the same Container. Little space is wasted; while adequate working space

is required. The system share by rationing space. To test this before committing

to use of the idea, is advised.

Older Mac OS X is another matter, both pre-Intel and post-Intel Mac. My macs

are on the cusp of old/newish; and latest macOS installed, is Mojave 10.14.6

I'd found with a physically partitioned HDD (rotational HD) the internal partitions

disappeared, when I installed two later macOS; High Sierra 10.13.6/Mojave 10.14.6.

To carefully work-around these is advised; reformat/reinstall may be necessary

And given the nature of beta versions, I'd not venture into those as such. Enough

trouble can be had without marginal use or limited incomplete systems. As beta

questions go without answers in this Community, that's another detail to know.

And this was unexpected; I'd little experience with these newer macOS. But have

two macs that can adequately run w/o issue, 'pre-Catalina' macOS/OS X for tests.

Not sure what your search engine capabilities are in RU. Since some that are good

in some aspects, may not be allowed in other areas. ~ Lately I've used 'duckduckgo'.

Use different machines for experimental use and upgrade testing; separate from

those you'd expect to be your workhorse models. Several sites online offer ideas.

My bookmarks are mostly official Apple support or similiar focus content pages.

Expect to use clones instead of re-installing; save time least repeated efforts waste

known-good gains. Make and keep good backups; Time Machine for some, clones

for others. Newer macOS has its own issues, answers, & where various backups go.

Take care & good luck!🌞🎣