Now, I have a 3 TB external for Mac OS at home, and another for Data, and another 8 TB Time machine, and another 3TB at the bank, and I use a cloud based backup, which I've never had to use which is $60, think going up to $120 yr…
Just be glad you hav never had to use your clue based backup.
But for this issue, DW, and maybe also an old copy of Quicken that I like, why not just then buy 2 new externals of 1 TB each, small and thin, and boot into them as needed?
That is what Artie and I were proposing.
NOTE: 1TB drives may be overkill 256GB should be ample unless you are loading a lot of data on the drive. That might bring an external SSD into an acceptable price range and give you better performance.
I'm on 10.12.6 now. I usually like to wait 8 months before upgrading OS... but anyway, I'll just wait for 13, and then do all this no? When I upgrade to 13, Mac puts a folder of the new OS, 13 in my apps right ? Then just copy that to the new small hardrives?
Wrong! You need to either install the OS on the external drives. Just copying a folder
will not work. The installation will also create Recovery drives on the external disks as well — and that can be invaluable if you ever have to use it.
Oh, it's Crashplan I use, in case of nuclear war and both my house and my bank burned down...
But could icloud take place of Crachplan? I suppose though Apple would charge as much…?
It is hard to compare Apples iCloud to other online backup plans as Apple provides free storage for items purchased through the App Store or iTunes Sore. but their monthly rates are 50GB — 99¢, 200GB — $2.99, 2TB — $9.99.
It would be nice to have a tiny partition in the OS for the old OS, for just the few 32 bit apps and then I would not have to buy or plug in the new tiny hard drives, but it sounds quite hairy to make that happen.. (create partitions into externals I already have..)
Your terminology "It would be nice to have a tiny partition in the OS for the old OS" is confusing because you cannot partition an OS, you can only partition a drive. The latter is doable, but as you surmise there are complications and the external drives would be a lot easier for you to maintain. Remember too that you will be applying updates, security patches, and even possible upgrades to the various OS configurations in the future.