Abstract: A storage device includes a first nonvolatile memory that includes memory cells, each capable of storing data of a first number of bits, a second nonvolatile memory of which memory capacity is larger than a memory capacity of the first nonvolatile memory, and a memory controller is configured to control the first nonvolatile memory to store data of a second number of bits that is smaller than the first number in each of at least a part of the memory cells according to a usage amount of the memory cells.

Abstract: A storage device includes a first nonvolatile memory that includes memory cells, each capable of storing data of a first number of bits, a second nonvolatile memory of which memory capacity is larger than a memory capacity of the first nonvolatile memory, and a memory controller is configured to control the first nonvolatile memory to store data of a second number of bits that is smaller than the first number in each of at least a part of the memory cells according to a usage amount of the memory cells.

Abstract: According to one embodiment, a storage apparatus includes a first storage medium which is nonvolatile, a second storage medium which is nonvolatile, a cache controller, and a main controller. An access speed of the second storage medium is lower, and a storage capacity of the second storage medium is larger than the first storage medium. The main controller controls the cache controller and accesses the second storage medium based on an access request from a host apparatus. The cache controller writes, in a multiplexed manner, data to be stored in the first storage medium to at least two areas in which deterioration of storage performance has been detected based on a result of access to the first storage medium.

Abstract: This invention relates to a control method, control device, and drive circuit for controlling the rpm of a spindle motor in order to reduce the rise time of the spindle motor. There is a discharge circuit (91-2) in the charge pump (91) of a spindle-motor driver (38). A control circuit (12) detects when the rpm of the spindle motor reaches near a target rpm, and discharges the charge pump (91). In this way, the rotation error near the target rpm is discharged, so it is possible to control and suppress overshoot. This makes it possible to reduce the rise time.

Abstract: This invention relates to a control method, control device, and drive circuit for controlling the rpm of a spindle motor in order to reduce the rise time of the spindle motor. There is a discharge circuit 91-2 in the charge pump 91 of a spindle-motor driver 38. A control circuit 12 detects when the rpm of the spindle motor reaches near a target rpm, and discharges the charge pump 91. In this way, the rotation error near the target rpm is discharged, so it is possible to control and suppress overshoot. This makes is possible to reduce the rise time.

Abstract: A method of adjusting a motor driving device which performs current-feedback PWM drive, the motor driving device, and an information storage device are provided. According to the present invention, a drive circuit is turned off by a control circuit, and a target current indication signal is gradually increased. The content of a register which stores the result of comparison between the output signal of a comparator circuit and the target current indication signal is then detected. If the content of the register is "1", i.e., if the output signal of the current sense circuit is smaller than a target current indication signal, the target current indication signal immediately before the output of the comparator circuit reaches "1" is stored as the reference value of the target current indication signal.