A method, system, and computer program product are provided to update file change log data to indicate that a change to a file in a file system has occurred. The Kalman filter receives predictive information from a model and measurement information from a projection electron beam lithography tool and compensates for factors which cause beam placement error such as wafer heating and beam drift. The advertisement selection engine includes a query processing module that retrieves advertisements associated with the advertisement query based on bids. The second arm abuts a spring stopper portion of the base member in a state where a load is exerted in a direction in which the coil portion is wound so that an inner circumferential surface of the coil portion is pressed against an outer circumferential surface of the support portion facing the engagement projecting portion.