Abstract: An information recording device includes a buffer memory, a buffer management unit and a phase adjusting unit. The buffer memory temporarily stores data to be written in a recording medium. The buffer management unit starts writing the data in the recording medium if a size of the data stored in the buffer memory exceeds a first predetermined size, and suspends writing the data in the recording medium if the size of the data stored in the buffer memory becomes less than a second predetermined size. Additionally, the phase adjusting unit starts adjusting a phase error between a signal synchronous to the data and a signal synchronous to a location on the recording medium when the buffer management unit starts writing the data in the recording medium, and finishes adjusting the phase error so that the phase error becomes substantially zero before the buffer management unit suspends writing the data in the recording medium.

Abstract: A servotrack writing apparatus (10) for use on computer disk drive workpieces (12). A writer controller (58) puts the writing apparatus (10) in the role of master to direct the workpiece (12) as a slave to position its read-write head (36) and to write the servotracks. A tracking section (54) provides a modulated light beam (72) from which a reflected portion is detected by a bi-cell photo sensor (70) and processed in the writer controller (58) to determine the position of a thru-hole (40) or a detection region (42) in the actuator arm (24) of the workpiece (12). The writer controller (58) may use a lock-in amplifier (102, 104) for the processing the reflected portion of the light beam (72). A reference arm (44) is locked and moved in a synchronous relationship with the actuator arm (24).