External objects represent entities that are not part of the Smalltalk universe. They are accessed using a unique handle which is interpreted depending on the actual entity that is represented.

Instance variables:
handle <ByteArray | ExternalAddress>

	initialize-release
	initialize

	private
	getHandle setHandle:

	instance creation
	new

	system startup
	install installSubclasses startUp:

	initialize-release	top
	initialize Initialize the receiver

	private	top
	getHandle Private. Return the handle used to represent the external entitiy.
	setHandle: Private. Set the handle used to represent the external entity.

	class initialization	top
	initialize ExternalObject initialize

	instance creation	top
	new Answer a new instance of the receiver (which is a class) with no indexable variables. Fail if the class is indexable.

	system startup	top
	install Notify all instances of the receiver that we're coming up on a new platform. Note: The default implementation does nothing since the general external objects are cleaned up by ExternalAddress>>startUp: but subclasses may implement this method so that the appropriate action for existing instances can be taken.
	installSubclasses Notify all the subclasses of ExternalObject that we are starting up on a new platform.
	startUp: The system is coming up. If it is on a new platform, clear out the existing handles.