What is the difference between Cache for Windows and Cache for MacOS?

There are different kernels but other than that you should be able to run the same ObjectScript code on both platforms and it will behalf identically.  If you are going to be doing file interactions, then I suggest using the %File library class which will make your code portable between Windows and UNIX file systems.  Likewise if you are calling out to other executables, you will need to instrument your code to call out appropriately based on your platform. 

Cache for Windows is supported as a server platform and Cache for MacOS is only supported as a development platform?

https://docs.intersystems.com/latest/csp/docbook/Doc.View.cls?KEY=ISP_te...