Does anyone know if it's possible to start from a pure Catalina installation of macOS and install a partition with Mojave? For the first time in forever I won't update macOS on my computer so that I can keep using a few 32-bit app, including http://www.halomd.net/.
I've done this to install a beta, but not to try to install an older macOS version from a newer release. If for some reason, the Mojave installer won't launch from Catalina, then you could create a bootable Mojave installer:
Greetings to halo MD fans! Unfortunately the original Mac Halo binary that MD wraps is itself 32 bit, but some hope lies in a project called wineskin. Look up the Porting Team discord or atomical’s Halo MD discord for some discussion...
You can install macOS (this also works for Catalina) on an external hard drive (I recommend an SSD if possible). This runs at native speed and you can use it to test/try anything without touching the internal disk.
Unless you have a very powerful host system running macOS in a VM is painfully slow. On a 2019 MacBook Air with 16GB or RAM running a virtualized macOS is crawling to render the Finder window.
The biggest problem with virtualizing macOS is that it’s built assuming that a half competent GPU is available, meaning that its software rasterizer is dog slow which is a big problem because no VM simulates a GPU that macOS supports. I’ve heard things about getting GPU passthrough working to fix this but I’ve not tried that myself.
Parallels specifically is much better than e.g. Virtualbox in my experience. Still not really pleasant—there's a lot of latency for some reason, unless you directly pass through the mouse as a USB device—but usable enough.
A few months ago I tried a Mojave and a few older versions of macOS in VirtualBox on a 2013 Thinkpad (Hackintosh) and had no problems with booting nor basic things like Finder and other operations with the GUI. I didn't try more graphics-intensive apps, however, but it was actually surprisingly fast and easy to install from an ISO created using the official source download, minus the workaround I needed for EFI booting from APFS. Building an app with Xcode (the reason for doing all this in the first place) also worked decently.
Did Snow Leopard still bundle Rosetta with the install? I thought that Snow Leopard still required a download of Rosetta that likely wouldn't be available now...
OSX VMs are so slowwww in a virtual environment though. I’ve tried doing it several times in parallels and they just crawl. Unless I’m doing something wrong.
My experience and knowledge about it has said that this is because of the reliance of OSX on GPU hardware. That means it won't ever perform well on any kind of software rendering. Some kind of GPU passthrough or sharing is needed to make it work acceptably.
It's got to be more complicated than that. I've used Parallels to run complex DX10 games such as a Tomb Raider 2013. I'm not sure what wizardry they use to make that happen, but it works really well.
Parallels is, perhaps not coincidentally, not as terrible at running macOS as some other solutions, but it's still fairly poor.
It's not. I've run macOS under a hypervisor with GPU passthrough and it's essentially as fast as on metal (I think you can see a single digit percentage difference in benchmarks). I don't think anyone has a soft 3D driver though for macOS guests. Parallels and VMware have both put a lot of work into getting some level of soft VM based 3D acceleration working for Windows guests, presumably because that's where the demand is. At the same time macOS has been built heavily around GPU for everything for a very long time now, initially as a way to improve even basic interface smoothness in Aqua back in the day. So it's a dog in pure software on a VM. It really needs a GPU.
FWIW, in the past VMware did officially have Mac Pros on the hardware compatibility list for ESXi (up to 5.5 I think? maybe the trashcan lasted longer). And that in turn would be legit for running a Mac guest. I've read you can sort of get it to work on other Macs like the Mini, though secure boot must be disabled and the T2 causes other issues. Otherwise you need to patch it, or go with KVM or some other alternative.
