Patent ID: 8832355

Claim:
A storage device comprising: a programmable device that realizes a first function of a circuit and a second function of a circuit corresponding to control data written in the programmable device, the programmable device realizing the first function when first control data is written in the programmable device, the first function including a first interface connecting to a cache memory, a second interface connecting to a nonvolatile memory, a writing circuit configured to save data stored in the cache memory into the nonvolatile memory, and an erase circuit configured to erase the data that has been stored in the nonvolatile memory; a saving instructing unit that instructs the programmable device with the first function to save the data stored in the cache memory into the nonvolatile memory; a writing unit that writes second control data instead of the first control data into the programmable device to change the first function without a reading circuit into the second function without the writing circuit, when electric power supply is resumed after occurrence of an abnormal shut-down of the storage device, the second function including the first interface, the second interface, the erase circuit, and a plurality of reading circuits configured to restore, in parallel, the data that has been saved in the nonvolatile memory into the cache memory when the second control data is written in the programmable device; and a restoring instructing unit that instructs the plurality of reading circuits of the programmable device with the second function to restore, in parallel, the data that has been saved in the nonvolatile memory into the cache memory, wherein the writing unit rewrites the first control data in place of the second control data when a data restoring process is completed as instructed by the restoring instructing unit.