JP2533384B2 - Magnetic storage device - Google Patents

Description

The present invention relates to a magnetic storage device, and more particularly to a magnetic storage device having a rotating head with a small diameter.

[Prior Art] First, the background of the present invention will be described. FIG. 3 is a block diagram showing an example of the configuration of a conventional magnetic storage device.
This magnetic storage device uses a rotary head type digital audio tape recorder (hereinafter referred to as R-DAT) as an auxiliary storage device of the external computer 1. In the figure, when the data from the external computer 1 is written on the magnetic tape 14, the data from the external computer 1 is given to the interface 2 via the line l1. The data of the line l1 is image information, audio information, arithmetic processing information in the external computer 1 or the like, and is transmitted for each information unit of two tracks on the magnetic tape 14 (hereinafter, this information unit is referred to as a frame). To be done. One frame includes, for example, 5120 bytes of data, and the external computer 1 divides each frame and outputs the divided data.

FIG. 4 is a diagram showing the contents of one frame on the magnetic tape 14. As shown in FIG. 4, one frame of the magnetic tape 14 is divided into a plurality of areas. That is, for example, the individual data areas a to e and the data areas a to e
1 depending on the parity areas Pa to Pe individually corresponding to
The frame is constructed. The 5120-byte data described above is divided and stored in data areas a to e each having a data amount of 1024 bytes. Parity area Pa ~
Pe has, for example, 128-byte data, and individually corresponds to the data in the data areas a to e. The data in the parity areas Pa to Pe are added in the interface 2 and used as an error correction code. In the R-DAT, parity is added in the signal processing circuit 7 in addition to the above, as will be described later, but the structure of one frame shown in FIG. 4 provides a higher reliability as an auxiliary storage device.

Returning to FIG. 3, such data is output from the interface 2 to the memory 3 such as a random access memory via the line l2 and to the signal processing circuit 7 via the line l3.

FIG. 5 is a diagram showing a storage area in the memory 3. Referring to FIG. 5, memory 3 is divided into eight storage areas M0 to M7, and each storage area M0 to M7 stores data for one frame.

In the memory 3, the data for one frame from the interface 2 is first stored in the storage area M0. At this time, the data in the storage areas M0 to M6 of the memory 3 are sequentially transmitted to the storage areas M1 to M7 to the right. Further, the data in the storage area M7 is normally erased. For example, as shown in FIG. 5A, when data of frame numbers N + 7 to N, which will be described later, are stored in the storage areas M0 to M7, respectively, frame numbers N + 8 and N + 9 are sequentially input. The memory 3 changes to the store state shown in FIG. 6 (b) → FIG. 5 (c). Interface 2
The input operation and so on are carried out in accordance with a control signal from the control circuit 4 formed of a microcomputer, for example.

The data taken in from the interface 2 to the signal processing circuit 7 via the line 13 is added with parity in the normal R-DAT. The data to which the parity is added is output to the amplifier 8 via the line l4. Amplifier 8
The data signal amplified by is transmitted to the write head WA via the line l5 and the write head WB via the line l6.
Is given to the magnetic tape 14 and written on the magnetic tape 14. The switching of the amplifier 8 is controlled by a signal synchronized with the rotation of the rotary drum 9 from the synchronizing circuit 13.

The writing heads WA, WB and the reading heads RA, RB described later are fixed to the cylindrical rotating drum 9.

FIG. 6 is a perspective view showing a configuration near the rotary drum 9. The rotary drum 9 is rotationally driven by the motor 6 around the axis in the direction indicated by the arrow 20. At this time, the servo circuit 5 controls the rotation speed of the motor 6 by the control signal from the control circuit 4. The magnetic tape 14 is run in the direction indicated by the arrow 21 by a capstan motor (not shown) or the like. Magnetic tape 14 is rotating drum 9
It is in contact with the side of at an angle of A1.

The writing heads WA and WB are provided on the diameter line of the side surface of the rotary drum 9. Similarly, the read heads RA and RB are also provided on the side surface of the rotary drum 9 along the one-diameter line. Writing head WA and reading head RA corresponding to this writing head WA
Are provided at an angle A2 in the circumferential direction of the rotary drum 9 and slightly offset in the axial direction. The angle A2 is, for example, 90 °.

FIG. 7 is a diagram showing how the write heads WA and WB run on the magnetic tape 14. Referring to FIG. 7, the write heads WA and WB scan the magnetic tape 14 in an oblique direction to form tracks A and B, respectively. The frame number described above is stored in a part of the subcode areas 16a and 16b. The data written on the magnetic tape 14 is read heads RA and RB corresponding to the write heads WA and WB, respectively.
Read by. Signals from the read heads RA and RB are amplified through the lines l7 and l8 shown in FIG.
Given to 10 each. At this time, the read head RA,
The RB individually reads the data on the tracks A and B formed by the corresponding write heads WA and WB.

Returning to FIG. 3, the data signal amplified by the amplifier 10 is output to the synchronizing circuit 11 via the line l9, and the synchronizing circuit 11 is synchronized with the clock signal from the clock generating circuit 15. The amplifier 10 is a synchronization circuit 13
The outputs of the read heads RA and RB are switched and output to the line l9 in accordance with the synchronizing signal from. The output of the synchronizing circuit 11 is sent to the signal processing circuit 12 via the line l10, and the signal processing circuit 12 corrects the data error. This error correction is performed based on the parity added by the signal processing circuit 7. The signal processing such as error correction at this time is performed by the synchronizing circuit 13 in synchronization with the signal processing such as the parity load in the signal processing circuit 7.

The data output from the signal processing circuit 12 is the line l12.
To the interface 2 described above. Normally, in the interface 2, the data is stored in the memory 3 via the line 12 and then the data is read from the memory 3 and output to the external computer 1.

FIG. 8 is a diagram showing a standardized recording format of a magnetic tape. Referring to FIG. 8, one recording area is
The sub-code areas 16a and 16b shown in FIG. 7 correspond to 33 blocks respectively, and the main code area corresponds to 130 blocks.

FIG. 9 (a) is a diagram showing the arrangement of the writing head and the reading head with respect to the rotary drum 90 having a normal diameter in the conventional R-DAT. For the rotating drum 90 having such a normal diameter, the winding angle A1 of the magnetic tape is 90 °. In this case, as shown in FIG. 9 (b), recording and reading of two pairs of heads were performed by one rotation of the drum.

Recording and reading timings in this case will be described with reference to FIG. FIG. 10 shows the signal processing circuit 7 shown in FIG.
3 is a timing chart of output signals for recording and reading from and. Referring to FIG. 10, the signal processing circuit 7 outputs the basic waveform A, and outputs the recording signal F at the rising and falling edges thereof. The signal processing circuit 7 outputs the reproduction signal G at the same time. The basic waveform A is given to the signal processing circuit 12 via the synchronizing circuit 13, and the signal processing circuit 12 operates with a phase difference from the basic waveform A. The basic waveform D is a signal synchronized with the basic waveform A output from the signal processing circuit 7. Since the servo is applied to the drum 90 and the magnetic tape 14 with the basic waveform A output from the signal processing circuit 7 as a reference, the reproduction signal G is read by the read head from the same position as the rising of the basic waveform D.

In the conventional example shown in FIG. 9 (a), FIG. 9 (b)
As shown in, crosstalk does not occur because recording and reading do not overlap. Therefore, as shown in FIG. 10, while the recording signal F and the reproduction signal G are being output, signal processing is performed throughout the output of the signal.

Next, how the recording recording F and the reproduction signal G shown in FIG. 10 are output from the signal processing circuit 12 and the amplifier circuit 10 will be described. Generally, the high-potential H section and the low-potential L section of the basic waveforms A and D are 15 msec. The signal processing circuit 7 and the signal processing circuit 12 have a counter of 0 to 141120 between them. Therefore, the count value from the rising or falling of the basic waveform A or the basic waveform D to the main code area is as follows when the normal diameter is 30 mm.

{141120 / (180/90)} × (33/196) = 11880. Here, the reason why the counter value 141120 is divided by 2 is as follows. Since the drum has a pair of read heads, the half cycle of the basic waveform A corresponds to 180 ° of the drum. This is because the magnetic tape is wound on the drum over 90 °, so that the data is read only in half of 180 °. The signal processing circuit 12 shown in FIG.
Includes a counter. This counter counts its count value in response to the rise of the basic waveform D,
Until, the subcode area 1 is read, and then the recorded data is checked with reference to the main code area.

[Problems to be Solved by the Invention] Generally, a magnetic tape needs to be wound around a head over a predetermined length during recording and reading. Normal diameter is
The wrap angle of the magnetic tape on the 30 mm rotating drum is 90 °. Therefore, in a rotary drum having a diameter smaller than 30 mm, the reading operation of the recording head and the reading head is as shown in FIG. 11, for example. That is, the winding angle of the magnetic tape with respect to the drum 90 becomes 90 ° or more, and when recording and reading are performed with one rotation of the rotating drum 90 using four heads, there is a partial overlap between the recording time and the reading time. And crosstalk occurs as shown in FIG. As a result, it has been difficult to realize a magnetic memory value having a small rotating drum with a small diameter.

Therefore, an object of the present invention is to provide a magnetic storage device having a small rotating drum having a small diameter.

[Means for Solving the Problems] Data recorded by a pair of recording heads having a pair of recording heads and a pair of reading heads on the circumference according to the present invention and being rotated in a predetermined direction. In a magnetic storage device including a rotary drum for reading data by a pair of read heads, the diameter of the rotary drum is such that one rotation of the drum allows writing by the pair of recording heads and reading by the pair of read heads. The operation is set to a minimum drum diameter that can be performed without overlapping in time, and a magnetic tape for storing and reading the data is wound around the circumference of the rotating drum at an angle larger than 90 °. The pair of recording heads and reading heads include first and second recording heads and reading heads provided at symmetrical positions with respect to the center of the rotary drum, respectively. Stores a first portion that requires confirmation by reading the recorded data and a second portion that does not require confirmation in a predetermined format. Further, the magnetic tape is the read head. Determining means for determining whether or not the magnetic tape is in the first portion when being read by abutting against the magnetic tape; and selectively selecting the magnetic tape only when the magnetic tape is in the first portion at the time of reading. And selective reading means for reading.

[Operation] In the magnetic storage device according to the present invention, the determination means determines whether or not the area where the data stored in the portion of the magnetic tape which is currently running is in contact with the read head needs to be read. Data is read only when the running portion of the magnetic tape is a main code area which requires data check by being read. Therefore, in the subcode area, even if the read portion and the recorded portion overlap, crosstalk may occur because the portion is not read.

[Embodiment] FIG. 1 is a block diagram of a magnetic memory device according to the present invention and corresponds to FIG. 3 described in the section of the prior art. First
Referring to the figure, in a magnetic memory device according to the present invention, an amplifier circuit 110 and a signal processing circuit 112 are different from those of a conventional one. That is, referring to FIG. 1, a signal processing circuit 112 for reading has a counter 101 for counting code areas recorded in response to rising or falling of a basic waveform D, and a predetermined magnetic tape 14. Memory 102 for storing the count value corresponding to the upper subcode area 1 and the sum of the subcode area 1 and the main code area
And a determination device 103 that determines whether the count value of the counter 101 is equal to the value stored in the memory 102, and the determination device 103 determines that the counter value matches the predetermined value stored in the memory 102. And a switching signal output device 104 that outputs a switching signal for starting or ending the reading. Further, the amplifier circuit 110 includes a read switch 111 which operates in response to the output signal of the switching signal output device 104.

Next, the operation of the magnetic memory device according to the present invention will be described with reference to FIG. FIG. 2 is a timing chart for explaining the operation of the magnetic memory device according to the present invention. Referring to FIG. 2, reproduction signal C is output in response to the rising signal of basic waveform D output from signal processing circuit 112.
At the same time, the counter 101 in the signal processing circuit 112 starts counting. By the way, the memory 102 in the signal processing circuit 112
The count value corresponding to the switching value from the subcode area 1 to the main code area and the switching value from the main code area to the subcode area 2 of the magnetic tape is stored in advance. This value is calculated as follows, for example.

The diameter of the rotating drum is now 25 mm. In this case, the count value when switching from the sub code area 1 to the main code area is as follows.

141120 / (180/108) x (33/196) = 14256 The reason why 180 is divided by 107 is as follows.
Even if the diameter of the rotating drum changes, the contact length of the magnetic tape required for recording and reading with the magnetic head is constant. Therefore, when the diameter of the rotary drum is 25 mm, the wrap angle of the magnetic tape is 108 °.

Next, the count number when switching from the main coat area to the sub code area 2 is expressed by the following equation.

141120 / (180/108) × {(33 + 130) / 196} = 70416 That is, the count values of 14256 and 70416 obtained by the above calculation are stored in advance in the memory 102.

With reference to FIG. 2, even after the signal processing circuit 112 operates in synchronization with the basic waveform D and the reproduction signal C is output, the value of the counter 101 which starts counting from the rise of the basic waveform D is stored in the memory 102. The signal from the switching signal output device 104 does not turn on the read switch 111 in the amplifier circuit 110 until it matches the value stored in. Further, after the counter value reaches another value in the memory 102, the signal lA from the switching signal output device 104 turns off the read switch 111 again. A timing chart of the gate signal lA from the switching signal output device 104 is shown at the bottom of FIG. Referring to FIG. 2, according to the present invention, the signal processing circuit 112 outputs the gate lA for taking out the read signal only while the recording signal B and the reproduction signal C do not overlap each other. Therefore, even if the recording signal B and the reproduction signal C partially overlap, crosstalk does not occur.

In the present invention, the area in which crosstalk may occur is limited to the subcode area in which the recorded data does not need to be checked, so there is a certain limit. The value of this limit can be obtained as follows. Now, the count value of the main code area is 141120 × 130/196 = 93600. Therefore, the time when the potential of 1A is High must be 93600 count value or more. Therefore, (main code → subcode count value)-(subcode → main code count value)> 93600. When the winding angle of the tape at this time is X, it can be obtained by solving the following equation.

{141120 / (180 / X)} × 33 / 196- {141120 / (180 / X)} × {(33 + 130) / 196)> 93600 By using this formula, X <108 This value is about the diameter of the rotating drum. It corresponds to the case of 25 mm.
Therefore, the minimum diameter of the rotary drum to which the present invention is applied is 25 mm.

In the above description, only the signal processing circuit 112 and the amplifier circuit 110 have been described. Since the other areas are the same as the contents of FIG. 3 described in the conventional technique, the description thereof will be omitted.

[Advantages of the Invention] As described above, in the present invention, the magnetic storage device includes the determination means, and determines whether the data stored in the read portion of the magnetic tape which is currently running is the data in the area that needs to be read. To do. Then, the data is read only when it is the data in the necessary area. Therefore, even if the read head traces the reproduced signal while the write head is writing the recording signal, the read operation is not performed in the area where the read is no longer necessary, so that crosstalk does not occur. . Therefore, the period during which the write head writes the recording signal and the period during which the read head traces the reproduced signal can overlap. As a result, it is possible to provide a magnetic storage device having a small rotating drum with a small diameter.

[Brief description of drawings]

FIG. 1 is a block diagram of a storage device according to the present invention,
FIG. 2 is a timing chart of signals output from the signal processing circuit of the magnetic memory device according to the present invention, and FIG. 3 is a conventional block diagram of the magnetic memory device for explaining the background of the present invention. FIG. 4 is a diagram showing the contents of one frame on the magnetic tape, FIG. 5 is a diagram showing the storage area in the memory shown in FIG. 3, and FIG. 6 is a perspective view showing the configuration near the rotary drum. FIG. 7 is a diagram showing how the recording head runs on the magnetic tape, and FIG. 8 is a diagram showing a standardized storage format of the magnetic tape, and FIG. Is the conventional R-DAT
FIG. 10 is a diagram showing a rotating drum in FIG. 10, FIG. 10 is a timing chart of signals output from a conventional signal processing circuit,
FIG. 11 is a diagram showing writing and reading states on a rotating drum having a small diameter. 102 is a counter, 102 is a memory, 103 is a determination device, 104 is a switching signal output device, 110 is an amplifier circuit, 111 is a read switch,
112 is a signal processing circuit. In the drawings, the same reference numerals indicate the same and corresponding parts.

Claims (1)

(57) [Claims] 1. A pair of recording heads and a pair of reading heads are provided on the circumference, and the data recorded by the pair of recording heads is rotated by a predetermined direction to obtain the data recorded by the first pair.
A magnetic storage device including a rotating drum for reading by a pair of reading heads, wherein the diameter of the rotating drum is such that one rotation of the drum allows writing by the pair of recording heads and reading by the pair of reading heads. Is set to a minimum drum diameter that can be executed without overlapping in time, and a magnetic tape for storing and reading the data is wound around the rotating drum at an angle larger than 90 °. The pair of recording heads and reading heads respectively include first and second recording heads and reading heads provided at symmetrical positions with respect to the center of the rotating drum, and on the magnetic tape, A first portion that requires confirmation by reading the recorded data and a second portion that does not require confirmation are stored in a predetermined format. Determination means for determining whether or not the magnetic tape is in the first portion when being read by contacting the read / write head, and selected only when the magnetic tape is in the first portion at the time of reading Magnetic storage device including selective reading means for selectively performing the reading.