Abstract: Embodiments of the present invention efficiently perform servo correction for prevention of propagation of a position error in a radial direction in self servo write (SSW). According to one embodiment, in SSW, a target position of a reference track TO in writing a servo write track TN is corrected. The target position is represented as a target value of a position signal calculated from a signal read by a read element. A signal indicating a deviation (a position error) from the target position (the target value) is referred to as PES. The SSW in this example performs correction of target positions in respective tracks using an impulse response of a servo system. Consequently, it is possible to efficiently and effectively prevent the propagation of position error in the SSW.

Abstract: Embodiments of the present invention provide a method of forming an initial servo-pattern for self servowrite, insusceptible to constraints of an output resolution of a driver circuit for driving an actuator, and a dynamic range. According to one embodiment, a cluster pattern made up of pattern blocks, each including a burst pattern, is written by use of a write element by pressing a head-support mechanism to a crash-stop, and a pattern block is newly written with a read element in states of being positioned at an inner peripheral side edge of the cluster pattern, an outer peripheral side edge thereof, and the center of two burst patterns included in the cluster pattern, respectively, thereby increasing a width of the cluster patterns in stages, so that an initial servo pattern for use in a propagation action is formed.

Abstract: Embodiments of the present invention efficiently perform servo correction for prevention of propagation of a position error in a radial direction in self servo write (SSW). According to one embodiment, in SSW, a target position of a reference track TO in writing a servo write track TN is corrected. The target position is represented as a target value of a position signal calculated from a signal read by a read element. A signal indicating a deviation (a position error) from the target position (the target value) is referred to as PES. The SSW in this example performs correction of target positions in respective tracks using an impulse response of a servo system. Consequently, it is possible to efficiently and effectively prevent the propagation of position error in the SSW.

Abstract: An executable command selection system and method are provided. A command is selected as the next-to-be-executed command when the execution waiting time for the command is less than or equal to a predetermined reference time. In addition, the command selected as the next-to-be-executed command has an execution waiting time greater than or equal to a scanning time. Once a command is selected as the next-to-be-executed command, calculation of execution waiting times for subsequent commands in the command queue stops. In this manner, when the number of commands in the command queue exceeds a predetermined number, the method of the present invention improves the efficiency of command execution for a storage device.

Abstract: A method and system to provide a command queue re-ordering method that can make the power save and reduction in acoustic noise. The command queue re-ordering method involves calculating the value of an evaluation function, Ev=A×T+(1?A)×Fun(L) (A is any number from 0 to 1, T is a latency required to execute a write command and/or read command, and Fun(L) is an evaluation function with a seek distance L) for the write command and/or read command, and selecting the write command and/or read command having the minimum value as a next command to be execute.

Abstract: An executable command selection system and method are provided. A command is selected as the next-to-be-executed command when the execution waiting time for the command is less than or equal to a predetermined reference time. In addition, the command selected as the next-to-be-executed command has an execution waiting time greater than or equal to a scanning time. Once a command is selected as the next-to-be-executed command, calculation of execution waiting times for subsequent commands in the command queue stops. In this manner, when the number of commands in the command queue exceeds a predetermined number, the method of the present invention improves the efficiency of command execution for a storage device.

Abstract: A method and system to provide a command queue re-ordering method that can make the power save and reduction in acoustic noise. The command queue re-ordering method involves calculating the value of an evaluation function, Ev=A×T+(1−A)×Fun(L) (A is any number from 0 to 1, T is a latency required to execute a write command and/or read command, and Fun(L) is an evaluation function with a seek distance L) for the write command and/or read command, and selecting the write command and/or read command having the minimum value as a next command to be execute.