System Introspection for System Analysis on Mobile Devices

Main DispatcherComponent DispatcherLogging DispatcherComponent Holdercontrols all client connections and manages a listof all connected clients. For example it adds anew client connecting to the probehandles the communication between the componentthreads and the client. It starts a componentthread when a client requests data, e.g.collecting laser datahandles the creation of a logging cycle on requestby a client. It adds all selected components to alogging cycle and interrupts the cycle on requestconnects the components of the robot and makesthem accessible to the probe. It controls howcomponent threads and logging cycles can receivenew data from components of the robot,e.g. how to read the laser range finderBesides each element of the probe holds a unique TAG. This TAG allows toidentify the element and allows direct addressing between elements.Main DispatcherThe main dispatcher controls the connection between the probe and the client.To monitor all clients connected it holds a list of all connected clients. Thelist is created and available the whole runtime of the probe. When a clientsends a connect command the main controller adds the client to this list. Anacknowledgment is send in return to the client. To monitor the connectionto each client in the list, the main dispatcher is responsible to exchange abeacon with each client. To achieve this, the list of connected clients alsoholds the count of beacons lost between client and probe. If the count exceedsa maximum, the connection is marked as disconnected. The maximum count<strong>for</strong> beacons missing can be set inside a configuration file. When a client sendsa disconnect command the main dispatcher removes the client from the list ofknown clients.Component HolderThe component holder is designed to capsule the communication between componentsof the robot and the probe. The idea behind the component holder isto create a single control instance that offers access to the robot components.25