| 摘要 |
PROBLEM TO BE SOLVED: To prevent buffer underrun in which a stream of write-in data sent from a host computer is broken. SOLUTION: Write-data outputted from a host computer 3 is inputted to a data transfer rate measuring section A, and stored in a data buffer of the inside. In the data transfer rate measuring section A, an average value of a transfer rate of a decided fixed time is measured, at the same time a compensation value in which the quantity of write-data left in the data buffer is included, is transmitted periodically to a spindle number of revolution control section B as a transfer rate average value in a real time. After the spindle of number of revolution control section B calculates the number of revolution being an optimum value based on the transmitted transfer rate average value and compares it with the present numbers of revolution, and transmits a control signal varying the number of revolution to a spindle motor D conforming to a fixed number of revolution variation curve.
|
