How to setup Mac OS10.15 Catalina and run SwiftUI
What you need - HardwareThe first thing you need is an external SSD Drive, The one that has worked well for me in the past is the Samsung T5 USB3.1 Type-C SSD, and you can get these from any retailer for approximately AUD $128 or a 1TB for around AUD$338 which is a good deal considering that I paid those rates for a 128GB last year. The product link is here.
What you need - SoftwareOn your current Mac go to the App Store and download the installation image for Mojave. The reason for that is the minimum requirements for installing Catalina is Mojave (10.14.4)
Let's get startedYes, that's all we need, connect the SSD Drive to your Mac (it comes with both cables for USB-C and USB-A) then press ⌘ + Space (or if you have changed your shortcuts - start Spotlight). Type Disk Utility and press enter. This will start the Disk Utility application, we need to format the SSD that comes with a FAT partition to a GUID Partition Map. The thing to keep in mind is that you could not get this option by default when you select the disk to format, you need to enable the Show All Devices option and then select the parent disk to format.
Once you format it with the GUID Partition Map, start the Mojave installation, select the SSD Drive as the destination.. What this will do is setup Mojave on your SSD and use it as if that was a newly installed system. The installation will take some time... once it is completed and you create your login, accounts, etc. Start Safari, log into your developer account and download the package to install Catalina. Once you finish it will start the download of the Catalina files and once completed, tada.... you have an installation of Catalina on your SSD. When you shut down the Mac, disconnect the SSD and start the mac again, it will boot into your older (current) OS.
Performance issuesI have not seen any, in fact I found it to be much better (not speed wise) but space wise, I get the full capacity of the SSD as my disk drive than a shared partition. I do not connect my existing drive to this installation because 1. I can avoid accidents and 2. I want to explore the OS by itself, not use my existing applications etc. Restarting or swapping OS is also quite fast, shutdown and restart is all under a minute, so happy days....
Bonus: SwiftUIFor running or testing SwiftUI you need to have Xcode 11 and Mac SO 10.15 (Catalina), we have just installed Catalina as per the instructions above, now from the developer account, download Xcode and when it finished downloading, double click and wait for it to extract itself, double click to run it, it would install the command line tools, etc that it requires and you are all set to now use SwiftUI and have a play with it.
You can keep an eye out on my blogs, twitter for articles, tips and *maybe* a book on SwiftUI coming soon.