The invention relates to apparatus which can be used to move a person supported on the apparatus between a lying position in which the apparatus is substantially flat on a support surface and a seating position supported by the apparatus. Whether a memory cell included in the memory cell string has been programmed is determined based on the voltage supplied to the first node. Two sets of the springs can be arranged for biasing the rod member to a central position relative to the housing. The variable volume systems can be implemented in a well logging tool and are capable of being calibrated downhole. Candidates for replication volumes are automatically selected and presented to the user or the administrator, and replication volumes are automatically allocated, without requiring the user or the system administrator to be concerned with the characteristics of the storage devices.