In a memory system in an embodiment, in a case of normal operation, a control unit returns a write completion response upon completion of reception of write data from a host, and writes the write data into nonvolatile memory in a multiple values. In a case of unordinary power-off, changeover to operation using a backup battery is conducted and the control unit writes dirty data that is not completed in writing into the nonvolatile memory, into the nonvolatile memory with two values. When next boot, the control unit reads the dirty data from the nonvolatile memory into the volatile memory, and thereafter writes the dirty data into the nonvolatile memory in a multiple values.

In a memory system in an embodiment, in a case of normal operation, a control unit returns a write completion response upon completion of reception of write data from a host, and writes the write data into nonvolatile memory in a multiple values. In a case of unordinary power-off, changeover to operation using a backup battery is conducted and the control unit writes dirty data that is not completed in writing into the nonvolatile memory, into the nonvolatile memory with two values. When next boot, the control unit reads the dirty data from the nonvolatile memory into the volatile memory, and thereafter writes the dirty data into the nonvolatile memory in a multiple values.

In a memory system in an embodiment, in a case of normal operation, a control unit returns a write completion response upon completion of reception of write data from a host, and writes the write data into nonvolatile memory in a multiple values. In a case of unordinary power-off, changeover to operation using a backup battery is conducted and the control unit writes dirty data that is not completed in writing into the nonvolatile memory, into the nonvolatile memory with two values. When next boot, the control unit reads the dirty data from the nonvolatile memory into the volatile memory, and thereafter writes the dirty data into the nonvolatile memory in a multiple values.

A control device includes a nonvolatile memory, a first processor, a first volatile memory coupled to the first processor, a second processor, and a second volatile memory coupled to the second processor, wherein the first processor is configured to transmit first data stored in the first volatile memory to the second processor by using electric power supplied from a backup power supply, the second processor is configured to store the first data in the second volatile memory, after storing the first data in the second volatile memory, the backup power supply stops supplying the electric power to at least one of the first volatile memory and the first processor, and the second processor is configured to store, in the nonvolatile memory, the first data stored in the second volatile memory.

An apparatus and method for memory backup are disclosed as being operational at a memory module that includes a volatile memory device but which is devoid of a non-volatile memory device. The memory module can emulate operations of a non-volatile memory on the memory module while the memory module is devoid of such non-volatile memory.

A memory manager in a computer system that ages memory for high performance. The efficiency of operation of the computer system can be improved by dynamically setting an aging schedule based on a predicted time for trimming pages from a working set. An aging schedule that generates aging information that better discriminates among pages in a working set based on activity level enables selection of pages to trim that are less likely to be accessed following trimming. As a result of being able to identify and trim less active pages, inefficiencies arising from restoring trimmed pages to the working set are avoided.

In a memory system in an embodiment, in a case of normal operation, a control unit returns a write completion response upon completion of reception of write data from a host, and writes the write data into nonvolatile memory in a multiple values. In a case of unordinary power-off, changeover to operation using a backup battery is conducted and the control unit writes dirty data that is not completed in writing into the nonvolatile memory, into the nonvolatile memory with two values. When next boot, the control unit reads the dirty data from the nonvolatile memory into the volatile memory, and thereafter writes the dirty data into the nonvolatile memory in a multiple values.

System and method to encode and decode raw data. The method to encode includes receiving a block of uncoded data, decomposing the block of uncoded data into a plurality of data vectors, mapping each of the plurality of data vectors to a respective bit marker, wherein the respective bit marker is shorter than said respective mapped data vector, and storing the bit marker in a memory to produce an encoded representation of the uncoded data. Encoding may further include decomposing the block of uncoded data into default data and non-default data, and mapping only the non-default data. In some embodiments, bit markers may include a seed value and replication rule, or a fractalized pattern.