You are correct, and the other one is AVAILDEV. Set it to false, and device names like CON only refer to the device when prefixed with "/dev/". Microsoft did h

You are correct, and the other one is AVAILDEV. Set it to false, and device names like CON only refer to the device when prefixed with "/dev/". Microsoft did have a reason to remove these features: compatibility with batch files. "\dev\" actually remained special in all later versions, in that it can always be used to open a device, even if that directory doesn't exist. This could break a common idiom in batch files to test if a path is valid: C:\> if exist \dev\nul echo Yup, still there (I don't have a recent version of Windows to test this on, interested to see if it still works!)