JPH0243242B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a read control system for reproducing data from a magnetic tape in a magnetic recording/reproducing device that records information in a diagonal band shape on a wide magnetic tape using a rotary head. It's about improvement. This method uses a wide magnetic tape as an information storage method for a large-capacity storage device, and uses a rotary head to record information on the magnetic tape in a diagonal strip shape with respect to the tape's longitudinal direction. In an ordinary magnetic tape device, information is recorded in the tape running direction, but in the above system, information is recorded in a strip shape diagonally with respect to the tape running direction. In this case, in order to recognize the band in which information is recorded, that is, the data stripe,
An ID block indicating the serial number of the data stripe is written on the data stripe. 1st
The figure shows the state of information recording on a wide magnetic tape used in a mass storage device. 1 is a magnetic tape. 2 is a data block and 3 is an ID block. 2 and 3 constitute a data stripe.
Arrow a indicates the running direction of the head, and arrow b indicates the running direction of the tape. The ID block is recorded by a servo writer when the magnetic tape is manufactured, and is not rewritten in the mass storage device thereafter. However, data blocks are written to and read from mass storage devices. Therefore, the conditions recorded on the magnetic tape are different between the ID block and the data block, the amplitudes of the read waveforms are not the same, and the read level of the ID block is often low. This relationship is shown in FIG. 4 is the read level of the ID block,
5 is the read level of the data block. If the voltages of the respective amplitudes are V ₁ and V ₂ , then V ₂ V ₁ is obtained. However, the signal detection level in the read control circuit of conventional large-capacity storage devices does not distinguish between the ID block and the data block, and the detection level is the same, which may result in incorrect signal detection in the ID block section. . If a reading error occurs in the ID block, the data stripe becomes unusable, resulting in a reduction in the number of usable data stripes per roll of magnetic tape.

An object of the present invention is to reduce ID block reading errors by detecting the amplitudes of the read waveforms of the ID block and data block at different levels. In other words, since the ID block was written on the magnetic tape at the time of shipment, the amplitude of the read waveform is smaller than that of a data block written in a mass storage device, as shown in Figure 2, so the amplitude detection level is This is to prevent reading errors in the ID block and data block by detecting with an amplitude detection circuit having an optimal value.
FIG. 3 is a block diagram of a circuit showing one embodiment of the present invention. The signal read waveform enters the amplifier 6 through the C line, is amplified, and then sent to the amplitude detection circuits 7 and 8.
to go into. The amplitude detection circuits 7 and 8 have different amplitude detection levels, and the amplitude detection circuit 7 has a high level,
Therefore, it is used for signal detection of the data block, and the amplitude detection circuit 8 is at a low level, and therefore used for signal detection of the ID block. Since the ID recognition signal enters the selection circuit 9 through the d line, the selection circuit 9 selects the output of the amplitude detection circuit 8 when detecting an ID block signal, and the output of the amplitude detection circuit 7 when detecting a data block signal. Send to e-line. It is possible to obtain an ID recognition signal in a mass storage device because it is necessary to read the ID block and data block separately.

In the above explanation, two amplitude detection circuits with different amplitude detection levels are used, but the comparison voltage that determines the amplitude detection level of the same amplitude detection circuit is determined depending on the ID block detection time and data block detection time.
The same holds true even if the recognition signal is used to switch between two values.

As described above, the present invention can improve the usability of stripes per roll of magnetic tape, and therefore improve the efficiency of using magnetic tape in mass storage devices.

[Brief explanation of drawings]

FIG. 1 shows the state of information recording on a wide magnetic tape. 1 is a magnetic tape, 2 is an ID block, and 3 is a data block. FIG. 2 shows the read levels of the ID block and data block. 4 is the read level of the ID block, and 5 is the read level of the data block. FIG. 3 is a block diagram of a circuit showing one embodiment of the present invention. 6 is an amplifier, 7 and 8 are amplitude detection circuits, and 9 is a selection circuit.

Claims (1)

[Claims] 1. A magnetic recording and reproducing device in which a magnetic tape has a data stripe including an ID block in which an identification number is recorded and a data block in which information is recorded, and information is recorded and reproduced in the data block. A reading device for a magnetic recording and reproducing device, characterized in that when reading an ID block and a data block recorded on the data stripe, an amplitude detection level of a read signal is switched between the ID block and the data block. Control method.