Electronic messages are personalized by rendering the messages to recipients in the voice of a predetermined human speaker. The task scheduler includes a time control portion having a common time to control a state of the plurality of tasks, and a task calculator calculating a slack disappearance time for each of the plurality of tasks. Each respective document in the plurality of documents comprises code for a unique web page available on the Internet that corresponds to the respective document. The invention also comprises unique monoclonal antibodies generated using MDO-leashed MDMA immunogens as well as unique conjugates and tracers. When the laser beam having passed through the optical system is irradiated to the semiconductor film through the mirror of the present invention, the conventionally observed faint interference can be reduced. The data writing method includes identifying at least one non-used segment among the physical writing segments of each of the physical writing units and writing a plurality of segment data streams into the physical writing units, wherein the non-used segments of the physical writing units are not used for writing the segment data.