I want to write Cocoa (Objective-C) based Service (equivalent to Windows Service - which has to keep running in background and stat itself when the machine boors up( and deploy into the machine. For example, Image Processing Service, this service has to be installed into the system and my client application (Objective-C) will contact them to give request (Asynchronous Calls). Then the service can process the request and post the response back to the client.