JPH043024B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for discriminating the recording method of data recorded on a recording medium, for example, the recording method of a floppy disk.

Conventional 5.25-inch floppies usually do not have the recording system written in track 00 on side 0 or 1, so the system should know in advance what recording system is written on the floppy disk to be used. The need arose.

The present invention thus relates to a recording method discrimination device that can discriminate between recording methods such as FM recording and MFM recording even if no special data is included in track 00.

In addition to the sector area, each track on a floppy disk has a pre-ampule, and the recording method is located at the leading gap of this pre-ampule.
FF (hexadecimal) for FM, 4F (16 decimal) for MFM
Since several bytes of decimal (digital) are recorded continuously, the present invention attempts to use this to discriminate the recording method.

FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows the first embodiment.
It is a signal waveform diagram of each part of the figure, and the signal line of figure 1 and 2
The numbers of the waveform diagrams in the figures are written in correspondence. 1 is the readout signal line of the floppy disk, 2 is the index signal line, 3 is the output line of monostable vibrator M1 by the index trigger, and 4 is the monostable multivibrator triggered by the edge after the output of monostable multivibrator M1. The output of M2, 5, is a data input section for presetting the counter C with the signal of M2, and 6 is the borrow output of the counter.

In FIG. 2, 7 is the output of counter C when the recording method is MFM recording, and 8 is the output of counter C when FM recording is used.

In the above configuration, when the index signal is input, an output as shown in FIG. 2 is output from M1, and the output is applied to the enable terminal CE of the counter C, so that the counter C is in a countable state during that time.
The counter has a numerical value N in advance in the data input section 5.
The readout signal (FIG. 2, 1) starts counting down when it becomes possible to count. The gap data at the beginning of the preamble section in the format of the protspee that performs discrimination is written as FF for FM recording, and 4E for MFM recording, so it is written in several bytes consecutively.
In recording, when the pulse width of 3 was set to 32 μs, the number of pulses of read signal 1 without jitter was 8,
In the case of MFM recording, there are six. Therefore, using the difference, when the output pulse width of M1 is t, the number of pulses in FM recording is m, and the number of pulses in MFM recording is n.
If the value N to be preset from the data input section 5 is set as m+n/2, the FM recording shown in FIG. It is possible to distinguish whether it is the MFM record shown in FIG. 2 or 7. After discrimination, the counter is preset by the output pulse of M2 and the operation is completed.

As described above, the recording method of a recording medium such as a floppy disk can be discriminated by using the data from immediately after the index is detected to just before the first gap of the preamble section of the data format where the first sector begins. can be easily done, so
There is no need to write the recording format in advance on track 00 on side 0 (1) of the floppy disk, unlike conventional methods, and this device can also be used to read floppy disks whose recording format is unknown. If you do this, you can do things like read it out without knowing it.

[Brief explanation of drawings]

Figure 1 is a circuit block diagram of the recording method discrimination device.
FIG. 2 1, 2, 3, 4, 7, and 8 are signal waveform diagrams of each part in FIG. 1. Here, 1 is a data signal line, 2 is an index signal line, M1 and M2 are monostable multivibrators, and C is a counter.

Claims (1)

[Claims] 1. A recording method discrimination device characterized in that the recording method is discriminated based on the content of data from immediately after detecting an index to immediately before the start of the first sector.