Interfaces are collections of method signatures. A interface type can hold any value that implements those methods. The empty interface is an interface type that specifies zero methods. A type assertion provides access to an interface underlying concrete value. Two interfaces are equal if they have equal concrete values and identical dynamic types, or if both are nil.
If you recently update your OS to Windows 10, you might notice that you are running out of space. If this is happening it might be because the old version of the Windows is not yet deleted from the disk, it is stored into "Windows.old" folder. And depending on the size of that version, it could be taking a lot of precious space.