Abstract: According to one embodiment, a quantum key delivery service platform includes a plurality of quantum key delivery devices and a management server. The server monitors a storage amount of the encryption keys in the plurality of quantum key delivery devices, records a consumption record of the encryption keys for each of the plurality of cryptographic communication devices, predicts a consumption amount of the encryption keys based on the consumption record of the encryption keys, and detects a sign of shortage of the encryption keys based on the storage amount of the encryption keys and a prediction result of the consumption amount of the cryptographic keys.

Abstract: According to one embodiment, an encryption/decryption execution environment encrypts and decrypts data of an application program while consuming an encryption key unit. A key exchange node accumulates an encryption key shared with a communication counterpart. A key accumulation amount monitoring function unit included in a key exchange node monitors an accumulation amount of the encryption key. A key accumulation amount notification function unit included in an application execution environment notifies a user of the application program or the application program of an accumulation amount of the encryption key acquired by the key accumulation amount monitoring function unit.

Abstract: A computer system includes a disk apparatus and a host computer including a journal file system. The disk apparatus includes a memory unit which is capable of permanently storing a journal, a storing control unit which stores a journal, which is sent from the host computer, in the memory unit, and an updating unit which executes data update corresponding to the journal stored in the memory unit in accordance with an instruction from the host computer. The journal file system of the host computer includes a writing unit which executes, each time the data on the disk apparatus is updated, writing of a journal, which corresponds to the data update, to the disk apparatus, and an informing unit which informs the disk apparatus of an instruction to execute the data update corresponding to the written journal.

Abstract: A data base system according to the present invention has a data base including at least one table and executing predetermined data processing by accessing to the data base in accordance with transactions. The data base system comprises a plurality of management process for executing data processing in accordance with assigned transactions, a plurality of buffers respectively provided for the plurality of management process, for holding partial copies of the table as blocks, data management table for storing a number of blocks held by each of the plurality of buffers, and transaction control section for assigning the transaction to the management process corresponding to the buffer which holds the largest number of blocks on the basis of the number of blocks stored in the data management table.