| 摘要 |
PURPOSE:To carry out a detecting process without reading again the control field, by deciding the defective track based on the reading flag byte and then securing a seeking action for the address designated by the flag byte under the prescribed conditions. CONSTITUTION:After the access information designated by the CPU is set to the register 1, the control field part of the track of the disk according to the access information is read with the flag byte to be applied to the register 4, FF6 and register 8. Then in case when a coincidence of comparison is obtained between the registers 4 and 1 with no detection of the CRC error, the track is decided nondefective. On the other hand, if no coincidence of comparison is obtained with no detection of the CRC error, the decision bit of the defective track within the reading flag byte is decided on with the FF6 set. Then the flag byte set to the register 8 is set to the register 1 to perform the seek action for the substitute track. In this way, the detecting process is given to the defective track in a short time without reading again the control field. |
