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 disk medium having a first recording region and a second recording region, a non-volatile semiconductor memory, and a controller. The controller is configured to write data of a first type into tracks of the first recording region that partially overlap with each other, to write for caching data of a second type into tracks of the second recording region, and to write for caching the data of the second type stored in the disk medium into the non-volatile semiconductor memory.

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 device includes a first nonvolatile storing unit having a predefined first management area, and a second nonvolatile storing unit configured to process data at a higher rate than the first nonvolatile storing unit. The first nonvolatile storing unit stores, in the first management area, first management information associated with the first nonvolatile storing unit, and second management information associated with the second nonvolatile storing unit.

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: A method of evaluating thermal relaxation in magnetic recording, and a pass-fail decision method for a magnetic disk read/write device which satisfies lifetime assurance conditions, are provided. The pass-fail decision method for a magnetic disk read/write device is a method of thermal relaxation degradation in a magnetic disk read/write device comprising a magnetic disk and a head which writes to and reads out from the magnetic disk, wherein prescribed signals are written to and recorded on the magnetic disk; the written and recorded signals are repeatedly read out at fixed time intervals over a prescribed time period; the error rate is measured for each reading-out; the relation between the logarithm of the elapsed time and the measured error rate is linearly approximated; and the error rate of the magnetic disk read/write device at a time exceeding the prescribed period is evaluated.