macos as vm guest

[Ryan Schmidt]

On Jun 25, 2020, at 20:50, Ryan Schmidt wrote:

> On Jun 25, 2020, at 18:06, Michael wrote:
> 
>> That's 10.15, that requires the root drive reformatting, with no compatible driver for older systems, right?
>> 
>> (Whether or not it's a better file system isn't the issue. 100% breaking compatibility with everything older is a bad move.)
> 
> Huh? On my 2012 MacBook Pro that I'm using for testing at the moment, I had no problem installing Catalina on an APFS volume, while also having Mojave and High Sierra installed on separate APFS volumes on the same partition, and having Lion and Sierra installed on separate HFS+ partitions, all on the internal disk. 

If you meant that older systems can't read APFS volumes, that's true. Sierra and later can read APFS, High Sierra and later converts your boot volume to APFS if it's an SSD, Mojave and later converts your boot volume to APFS no matter what type of disk it is. El Capitan and earlier can't read APFS. If you have data you want to share with El Capitan and older, use an HFS+ disk.

Last time we got a new filesystem it was similar. Mac OS 8.1 introduced HFS+. Mac OS 8.0 and earlier could not read it. This wasn't a big problem. You could still keep any data you wanted to share with older systems on an HFS disk.