COMPUTER SYSTEM HAVING DISK CACHE DEVICE

PURPOSE:To accelerate not only input processing speed but output processing speed by using a nonvolatile memory part and a volatile memory part to form a disk cache device. CONSTITUTION:A disk controller 14 receives an output request from an input/ output controller 13 and then turns off the two bits of a flag device. Then an included information storing dvice 17 is used to check whether the data to be written is included in the volatile part of a disk cache device 16. If not, the volatile memory transfer bit of a flag device 19 is turned on. While an idle area is secured for the nonvolatile part of the device 16 if the data is included in the volatile part of the device 16. In this case, an idle area bit is turned on for the device 19. Then the data is transferred, and at the same time the writing is carried out to the volatile part without fail. While the writing is carried out to the nonvolatile part only when the transfer bit of the nonvolatile memory of the device 19 is turned on. When the data transfer is over, it is informed to the controller 13.