| 摘要 |
PURPOSE:To prevent the occurrence of an over-run error by keeping a disc data transfer speed at a high level when the usage frequency of a system bus is at a low level, and reducing an effective data transfer speed when the usage frequency of the system bus becomes a high level. CONSTITUTION:When a data stored at a disc device 3 is read out to a system bus 1, the usage frequency of the system bus is detected with a bus usage status detection means 23. And when the usage frequency is at the low level, by transferring directly the data read out from the disc device 3 by a disc controller 25 within a disc control device 2 to the system bus 1 through a first-in first-out memory 21c, a high speed data transfer can be preformed. When the usage frequency of the system bus is at the high level, the data in the disc controller 25 is DMA-transferred temporarily to a data buffering memory 26, and the data stored at the data buffering memory 26 is DMA-transferred to the first-in first-out memory 21c. Thereby, the occurrence of the over-run error can be prevented by reducing the data transfer speed.
|
