You can download them rather cheap from apple, I think it's around $29 for a copy.
I had a disk laying around, since my stephdaughter has a mac. No serial numbers on OS X, since apple assume you owe some mac hardware, to get it installed somewhere, wich I do
, I even has an old macbook laying around.
Check out youtube for videos on how to install OS X in virtualbox, since there are some steps to follow to get it to work correctly.
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AGK user - novice
Did Amiga / AMOS programming in the 90's, just started programming again with AGK.