Patent ID: 8904065

Claim:
A buffer management device comprising: a buffer memory configured to manage a storage area according to a credit unit having a predetermined data size and to temporarily store write data requested to be written by a write command from an external device; a current-credit storing module configured to store a number of credits currently available for the buffer memory as a current credit value; a reserved-credit storing module; a transfer controller configured to register a number of credits necessary to temporarily store the write data in the reserved-credit storing module as a reserved credit value prior to transfer of the write data from the external device to the buffer memory; and a subtractor configured to subtract the reserved credit value registered in the reserved-credit storing module from the current credit value stored by the current-credit storing module and to output a subtraction result as an available credit value, wherein the transfer controller includes a converter configured to convert the write data into one or more credit units and at least one of a remainder for a beginning region of the write data and a remainder for an ending region of the write data, the remainders being determined based on a logical address of the write data, and each remainder having a data size that is less than the predetermined data size of the credit unit, and wherein the reserved credit value registered by the transfer controller is a sum of one credit for each of the credit units and one credit for each of the remainders.