A buffered peripheral system comprises a backup memory and a primary control unit which has a buffer memory for temporarily storing a copy of the contents of a buffer memory which stores data to be written to a peripheral device and a control device for issuing a command necessary to write the block stored in the buffer memory device to the peripheral device. The primary control unit also includes a recording device for recording the block number corresponding to the block which was most recently written to the peripheral device. The blocks of data which have been written to the peripheral device is then deleted from the backup memory to make room for storing further blocks of data. The system further has a backup control unit substantially identical to the primary control unit. Only the primary control unit normally operates to control the writing to the peripheral device. Upon detection of the failure of the buffer memory in the primary control unit, the backup control unit completes the operation of writing to the peripheral device by retrieving the blocks of data to be written to the peripheral device from the backup memory device using the block number information.