WORM guarantee memory device

It is a disk array system is provided which in particular allows the use of a WORM function if the disk array system uses the RAID system. When receiving a write request from a computer (100) is determined on the basis of the contents of write inhibit information, whether the writing of the write data from the computer is possible. If the writing is possible, a guarantee code for the transmitted data is generated, and write inhibit information are generated, indicating that the region in which the data is stored, is no longer writable. The write inhibit information generated is stored in the guarantee code of the guarantee code with the write disable information is assigned to the area, are stored in the computer (100) received data, and the data, which is associated with the write lock information of the guarantee code, in a cache memory, (230) and / or a disk drive (270) is stored. When writing of the data from the computer (100) is not possible, the computer (100) is informed.