The invention relates to methods and apparatus that efficiently convert a single-ended input signal to a differential output signal at high speeds so that a non-inverted differential output and an inverted differential output maintain a true differential phase relationship even at relatively high frequencies of input data. Transaction logs received from the source database are applied to a point-in-time copy of the source database to create recovery milestones comprising database blocks that can be used to provision virtual databases. The distance between the first and second magnetic assemblies may be decreased by applying a force to at least one of the first and second actuating portions. Upon expiration of a timeout associated with a security level, the set of permissions associated with the security level are then enforced against at least one managed object while the user session continues.