RECORDING AND ERASING METHOD OF FILE MARK

摘要

PURPOSE:To improve the system performance by writing a signal of a single frequency higher than the basic clock frequency written to an indicator part to a part of a data part to record a file mark and writing a single frequency to the rest of the data part to erase the file mark respectively. CONSTITUTION:When a file mark is written to a data part D, a mark write pulse MWPb is produced in place of a write gate pulse (a) and supplied to a timer circuit 22 through an OR gate 28 to produce a gate signal (e). The signal (e) opens an AND gate 14 and is written to a data part after detection of a disk medium 10 to be used as a file mark. When this file mark is erased, an index and an address are detected. Then a mark erasion pulse (c) is produced in the timing equivalent to the middle of the data part. An approximately entire area of the data part is written with the pulse (c) together with the file mark written previously with a division output (f). Thus the file mark is erased.