STORAGE DEVICE
A storage device of an embodiment includes a voltage measurement unit that measures a voltage of power supplied from a host, a volatile memory, a non-volatile memory including a saving area and a normal area, a data compression and decompression unit, and a controller. The controller includes a power-supply voltage determining unit which compares the voltage measured by the voltage measurement unit to a predetermined threshold value, a data saving unit which writes compression user data obtained by compressing user data by the data compression and decompression unit in the saving area when the voltage is less than the predetermined threshold value and the user data is included in the volatile memory, and a data rewriting unit which writes the compression user data that is decompressed in the normal area when the compression user data is included in the saving area at the time of supplying the power.
1 . A storage device, comprising:
a voltage measurement unit that measures a voltage of power supplied from a host;
a volatile memory;
a non-volatile memory that includes a saving area and a normal area;
a data compression and decompression unit; and
a controller that includes a power-supply voltage determining unit which compares the voltage measured by the voltage measurement unit to a predetermined threshold value, a data saving unit which writes compression user data obtained by compressing user data by the data compression and decompression unit in the saving area when the voltage is less than the predetermined threshold value and the user data is included in the volatile memory, and a data rewriting unit which writes the compression user data decompressed by the data compression and decompression unit in the normal area when the compression user data is included in the saving area at the time of supplying the power.
2 . The storage device according to claim 1 , wherein the controller includes the data compression and decompression unit.
3 . A storage device, comprising:
a voltage measurement unit that measures a voltage of power supplied from a host;
a volatile memory;
a non-volatile memory that includes a saving area and a normal area; and
a controller that includes a power-supply voltage determining unit which compares the voltage measured by the voltage measurement unit to a predetermined threshold value, a data saving unit which converts user data to a predetermined format and writes the user data in the saving area when the voltage is less than the predetermined threshold value and the user data is included in the volatile memory, and a data rewriting unit which writes the user data in the normal area when the user data is included in the saving area at the time of supplying the power.
4 . A storage device, comprising:
a reserve power supply;
a voltage measurement unit that measures a voltage of the reserve power supply;
a volatile memory;
a non-volatile memory that includes a saving area and a normal area; and
a controller that includes a power-supply voltage determining unit which compares the voltage measured by the voltage measurement unit to a predetermined threshold value, a data saving unit which writes user data in the saving area when the voltage is less than the predetermined threshold value and the user data is included in the volatile memory, and a data rewriting unit which writes the user data in the normal area when the user data is included in the saving area at the time of supplying the power.
5 . The storage device according to claim 4 , further comprising
a data compression and decompression unit,
wherein the data saving unit writes compression user data obtained by compressing user data by the data compression and decompression unit in the saving area when the voltage is less than the predetermined threshold value and the user data is included in the volatile memory, and
the data rewriting unit writes the compression user data decompressed by the data compression and decompression unit in the normal area when the compression user data is included in the saving area at the time of supplying the power.
6 . The storage device according to claim 5 , wherein the controller includes the data compression and decompression unit.
7 . The storage device according to claim 4 , wherein the data saving unit converts user data to a predetermined format and writes the user data in the saving area when the voltage is less than the predetermined threshold value and the user data is included in the volatile memory.
8 . The storage device according to claim 1 , wherein the compression user data is deleted when the voltage is greater than the predetermined threshold value and the compression user data is included in the saving area.
9 . The storage device according to claim 1 , wherein the writing in the saving area is performed in a binary recording scheme.
10 . The storage device according to claim 2 , wherein the compression user data is deleted when the voltage is greater than the predetermined threshold value and the compression user data is included in the saving area.
11 . The storage device according to claim 2 , wherein the writing in the saving area is performed in a binary recording scheme.
12 . The storage device according to claim 3 , wherein the user data of the saving area is deleted when the voltage is greater than the predetermined threshold value and the user data is included in the saving area.
13 . The storage device according to claim 3 , wherein the writing in the saving area is performed in a binary recording scheme.
14 . The storage device according to claim 4 , wherein the user data of the saving area is deleted when the voltage is greater than the predetermined threshold value and the user data is included in the saving area.
15 . The storage device according to claim 4 , wherein the writing in the saving area is performed in a binary recording scheme.
16 . The storage device according to claim 5 , wherein the compression user data is deleted when the voltage is greater than the predetermined threshold value and the compression user data is included in the saving area.
17 . The storage device according to claim 5 , wherein the writing in the saving area is performed in a binary recording scheme.
18 . The storage device according to claim 6 , wherein the compression user data is deleted when the voltage is greater than the predetermined threshold value and the compression user data is included in the saving area.
19 . The storage device according to claim 6 , wherein the writing in the saving area is performed in a binary recording scheme.
20 . The storage device according to claim 7 , wherein the user data of the saving area is deleted when the voltage is greater than the predetermined threshold value and the user data is included in the saving area.