This invention improves the access performance of a storage medium and prolongs the life of the storage medium while preventing a situation in which a response to a write request is delayed to cause a write error. A storage control apparatus includes a rearrangement starter that starts data rearrangement processing in which fragmented data, which has been determined that data corresponding to a logical address area in a logical address space used by a host computer to access a storage medium are fragmented and stored in a plurality of physical address areas in a physical address space of the storage medium, is written in a continuous physical address area in the storage medium; and a rearrangement controller that evaluates, when receiving a write request from the host computer during the data rearrangement processing, whether the data rearrangement processing improves access performance to the storage medium, and instructs to continue the data rearrangement processing if the access performance is improved, but cancel or interrupt the data rearrangement processing if the access performance is not improved.

An invention is provided for handling target disk access requests during disk defragmentation in a solid state drive caching environment. The invention includes detecting a request to access a target storage device. In response, data associated with the request is written to the target storage device without writing the data to the caching device, with the proviso that the request is a write request. In addition, the invention includes reading data associated with the request and marking the data associated with the request stored in the caching device for discard, with the proviso that the request is a read request and the data associated with the request is stored on the caching device. Data marked for discard is discarded from the caching device when time permits, for example, upon completion of disk defragmentation.

A method of determining causes of external fragmentation in a memory. The method includes collecting information associated with release of an area of the memory by an application, storing the information in the area of the memory, and analyzing the information to determine why the area of the memory has not been reallocated to any application. In embodiments wherein a first portion of an area of a memory is allocated to an application by an allocator and a second portion of the area of the memory is released by the allocator, the method includes storing in the second portion of the area of the memory an indicator indicating that the second portion is a remaining portion, collecting information associated with release of the second portion, storing the information in the second portion, and analyzing the information to determine why the second portion is not reallocated to any application.

A method of determining causes of external fragmentation in a memory. The method includes collecting information associated with release of an area of the memory by an application, storing the information in the area of the memory, and analyzing the information to determine why the area of the memory has not been reallocated to any application. In embodiments wherein a first portion of an area of a memory is allocated to an application by an allocator and a second portion of the area of the memory is released by the allocator, the method includes storing in the second portion of the area of the memory an indicator indicating that the second portion is a remaining portion, colleting information associated with release of the second portion, storing the information in the second portion, and analyzing the information to determine why the second portion is not reallocated to any application.

Accessing a file on a sequentially accessed storage device such as a magnetic tape often involves bypassing valid files and gaps between valid files. Presently taught is a method of copying valid files being bypassed to a second sequentially accessed storage device while not copying the gaps. When a read target file is reached, the read target file is read. During a write to a file writing position, valid files are copied to the second sequentially accessed storage device until the file writing position is reached and the file is written at the end of the valid files on the second sequentially accessed storage device.

A data storage system can automatically improve the layout of data blocks on a mass storage subsystem by collecting optimization information during both read and write activities, then processing the optimization information to limit the impact of optimization activities on the system's response to client requests. Processing read-path optimization information and write-path optimization information through shared rate-limiting logic simplifies system administration and promotes phased implementation, which can reduce the difficulty of developing a self-optimizing storage server.

A method for performing data fragmentation reduction control of a memory device in a predetermined communications architecture with aid of fragmentation information detection, associated apparatus and computer-readable medium are provided. The method may include: utilizing a memory controller to receive a first command from a host device through a transmission interface circuit of the memory controller; utilizing the memory controller to perform discontinuity-related calculation to generate a discontinuity-related calculation result for generating a data fragmentation degree, and send a first response; utilizing the memory controller to receive a second command from the host device through the transmission interface circuit; and utilizing the memory controller to send a second response to the host device through the transmission interface circuit to return the data fragmentation degree to the host device, for selectively performing data fragmentation reduction according to a determination result of the host device.

In a method of operating a storage device including at least one boot logical unit (LU), a first request is received to check whether a boot code stored in the at least one boot LU is fragmented. A first response including first information is output in response to the first request. The first information indicates whether the boot code is fragmented. When it is determined based on the first information that the boot code is fragmented, a second request is received to perform a defragmentation on the boot code. The defragmentation is performed on the boot code in response to the second request so that the boot code has physical continuity.

A memory system (100) includes a memory (2) including a plurality of pages (21) on each of which data can be arranged and a defragmenting device (4) that rearranges the data arranged on the plurality of pages (21). The memory (2) includes a plurality of tiles (22) each including one or more pages. Each of the plurality of tiles (22) is configured to be capable of transitioning among a plurality of states in which power consumption suppression rates are different. The plurality of states include a low power consumption state different from a power-off state. The defragmenting device (4) rearranges the data such that the tile (22) in which high access frequency data are collected and the tile (22) in which low access frequency data are collected are present.

In a method of operating a storage device including at least one boot logical unit (LU), a first request is received to check whether a boot code stored in the at least one boot LU is fragmented. A first response including first information is output in response to the first request. The first information indicates whether the boot code is fragmented. When it is determined based on the first information that the boot code is fragmented, a second request is received to perform a defragmentation on the boot code. The defragmentation is performed on the boot code in response to the second request so that the boot code has physical continuity.