US 2012/0239865 A1Published application

Storage device

AssigneeHitachi ULSI Systems Co., Ltd.

InventorsMasahiro Matsumoto, Takayuki Okinaga, Shuichiro Azuma, Shigeru Takemura, Yasuyuki Koike, Kazuki Makuni

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Abstract

A storage device realizing an improvement in rewrite endurance of a nonvolatile memory and an improvement in data transfer rate of write and read operations is provided including a nonvolatile memory; a volatile memory for storing file management information of the nonvolatile memory; a controller for controlling the nonvolatile memory and the volatile memory; and a power supply maintaining unit for supplying power to the nonvolatile memory, the volatile memory, or the controller upon power shutdown. The controller reads the file management information in the nonvolatile memory upon power-on and writes the same in the volatile memory, and read and write operations are performed based on the file management information in the volatile memory, and the file management information in the volatile memory is written in the nonvolatile memory upon power shutdown.

Claims2

Dependent claims

A semiconductor storage device connectable to a host, the storage device comprising:

a package;
a controller disposed in said package and having an interface circuit configured to control data input and output between the host and the storage device so that the semiconductor storage device is operated as a drive compatible to a hard-disk-drive as viewed from the host;
a first memory unit configured with flash memories disposed in said package, having a storage capacity of at least 16 gigabits, and configured to provide a file management information section, which is configured to store file management information of an operating system for the host, and a data section configured to store data sent from the host in the data section, wherein the file management information is to be referred to when the host accesses the data section;
a second memory unit configured with random access memories disposed in said package,
wherein the controller is configured to:
(1) read file management information from the file management information section in the first memory unit configured with flash memories and write the same in the second memory unit configured with random access memories in response to startup of the host;
(2) when, during normal operations of the host, an access of read or write from the host to the storage device is observed, perform read and write operations from the host to the storage device by referring to the file management information stored in the second memory unit configured with random access memories instead of the file management information in the semiconductor nonvolatile memory unit, and update the file management information within the second memory unit configured with random access memories;
(3) during normal operation of the host, perform allocation of destinations for saving data sent from the host either in the first and second memory units based on a condition set in advance;
and
(4) read the updated file management information recorded in the second memory unit configured by random access memories and write the same in the first memory unit configured with flash memories in response to a normal shutdown operation in the host.

7 more elements

A semiconductor storage device connectable to a host, the storage device comprising:

a package;
a controller disposed in said package and having an interface circuit configured to control data input and output between the host and the storage device so that the semiconductor storage device is operated as a drive compatible to a hard-disk-drive as viewed from the host;
a first memory unit configured with flash memories disposed in said package and configured to provide a file management information section, which is configured to store file management information of an operating system for the host, and a data section configured to store data sent from the host in the data section, wherein the file management information is to be referred to when the host accesses the data section;
a second memory unit configured with one of static and dynamic random access memories disposed in said package, and
a power supply maintaining unit disposed in said package and including an electric capacitor having a capacity of at least 0.1 F,
wherein, while the host is under a normal operation, the semiconductor storage device is driven by electric power supplied by the host, and the electric capacitor is charged by the electric power supplied by the host, and
wherein the controller is configured to:
(1) read file management information from the first memory unit configured with flash memories and write the same in the second memory unit configured with one of static and dynamic random access memories in response to startup of the host;
(2) perform read and write operations from the host to the storage device by referring to the file management information stored in the second memory unit configured with the random access memories instead of the file management information in the first memory unit configured with flash memories, and update the file management information within the second memory unit configured with the random access memories during normal operations of the host when an access of read or write from the host to the storage device is observed;
(3) read the updated file management information in the second memory unit configured with the random access memories and write the same in the first memory unit configured with flash memories in response to a normal shutdown operation in the host;
and
(4) when an unexpected power shutdown occurs on the host side, switch power supply connection from the host to the power supply maintaining unit and control to cut off a signal from the host and read the updated file management information in the second memory unit configured with the random access memories and write the updated file management information in the first memory unit configured with flash memories with electric power supplied from the power supply maintaining unit.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/486,132Filed 1 Jun 2012
Priority: JP 2006-2174369 Aug 2006
Published: 20 Sep 2012
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G06F 11/1441
At system level: resetting or repowering
G06F 12/0246
Memory management in non-volatile memory, e.g. resistive RAM or ferroelectric memory: in block erasable memory, e.g. flash memory
G06F 3/0616
Improving the reliability of storage systems: in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
G06F 3/0656
Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices: data buffering…

Family

Application12/376,665Continuation · filed 6 Feb 2009
Application13/486,132Continuation
US 2010/0180068 A1Published application
US 8,205,034 B2Related patent
US 8,504,762 B2Related patent
US 2012/0239865 A1This patent

From the US filing history. Foreign family members aren’t listed.