Abstract: Disclosed in the present invention is an electromagnetic-based haptic device that utilizes a flat wire coil type to provide the user with kinesthetic feedback in mid-air without direct contact. The invention comprises an array of flat wire coils, a localization system, a cooling fluid source, a magnetic agent attached to a stylus or a wearable device, current drivers and computer software. The flat wire coil comprises longitudinal packed flat conductive turns, each two turns are separated by an axial air gap. The cooling fluid source generates a fluid flow to pass over the surfaces of the coils to dissipate the heat generated by the device during the operation. The array of flat-wire coils is used to generate controlled magnetic fields and magnetic field gradients at a point in the workspace, the magnetic agent is attached to a wearable device or a handhold stylus to translate the magnetic fields/magnetic fields gradients to forces/torques feedback and thus haptic sensation.

Abstract: The present invention provides a method of implementing a fault-tolerant mutual exclusion lock. The present invention records in a lock structure the IDs of all processes whose failure can lead to the permanent unavailability of the lock. When a process finds the lock unavailable and suspects a permanent failure, it queries the programming environment about the status of all or some of the processes that could have caused the lock's unavailability. If the programming environment determines that these processes have failed, the live process tries to usurp the lock. If it succeeds, it executes some recovery mechanism and frees the lock or proceeds to operate on the objects protected by the lock. The method guarantees recovery from process failures.