ioclasscount displays the instance counts of OSObject-based C++ classes in the kernel, incremented by the number of direct subclasses that have an instance count of at least 1. For example, if IONetworkController is not directly instantiated, but its direct subclass IOEthernetController has any instances, then IONetworkController's instance count will be at least 1; if another direct subclass such as IOFWController has any instances, then IONetworkController's instance count will be at least 2; and so on.