Patent ID: 8832361
Filing Date: 2014-09-09
Classification: G06F,G11C

Abstract:
1. A storage device comprising: a semiconductor memory which has memory areas, a part of the memory areas being assigned to a user area which can be accessed from outside, the user area including allocation units (AUs), each management unit including recording units (RUs); a controller instructing to write data to the semiconductor memory in accordance with a request the controller receives; a first register provided in the controller and holding a class value corresponding to a performance class of the storage device; and a second register provided in the controller and holding information of a size of an AU, the size of the AU being memory management information used to manage the user area, wherein a worst average write performance of the storage device, which is an average of measured sequential writes performance, is larger than or equal to performance specified by the class value held in the first register, a write size of each of the sequential writes is a size of one of the RUs, and the first and second registers are accessible from outside.