JP3293608B2 - Magnetic disk drive and data writing / reading method therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a logic circuit for reading data recorded on a disk in a magnetic disk drive and controlling division of the data into physical data lengths.

[0002]

2. Description of the Related Art In a conventional magnetic disk drive using a data surface servo, an index / sector pulse signal serving as a base point of read / write control is transmitted in accordance with servo information read from a servo area of a disk surface on which data is recorded. Only one was output. That is, FIG.
, The read servo information Sn, S (n +
1), index sector pulse signals ISPn, ISP (n + 1), ISP (n + 2) according to S (n + 2), etc.
2) etc. are formed, and based on this, the corresponding data ID
Read / write control such as n, ID (n + 1), ID (n + 2) has been performed. That is, one read / write operation has been executed for one servo area. The above-mentioned prior art is disclosed in, for example, JP-A-1-194170.

[0003]

In the above-mentioned prior art, even if the logical data length determined by the interface between the magnetic disk device and the host controller is determined to be shorter than the physical data length, the physical data length and Since the difference in the logical data length is not considered, there is a problem that the shortest logical data length is determined by the physical data length.

Furthermore, if the logical data length is shorter than the physical data length, the surplus physical data area cannot be used as an effective data area, causing a problem that the total storage capacity is reduced.

[0005] Furthermore, when the portion for generating the index / sector pulse signal in the servo area becomes unreadable due to scratches or the like, there is another problem that the data area in the servo area cannot be read.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic disk drive capable of realizing a logical data length shorter than the physical data length and utilizing a surplus physical data area as an effective data area.

Another object of the present invention is to provide a case where a servo area becomes unreadable due to a scratch on a disk surface, and as a result, data recorded in a data area becomes impossible.
It is an object of the present invention to provide a magnetic disk drive that enables the reading.

[0008]

According to the present invention, servo information recorded on a magnetic disk is read, and a write / read control signal is formed based on the read servo information. In a magnetic disk drive that performs write / read control of data subsequent to servo information based on the read / write control signal, a plurality of write / read control signals are transmitted at different timings based on the servo information. Based on a plurality of formed write / read control signals, write / read control of data read from the magnetic disk following servo information or data recorded on the magnetic disk following servo information. By doing so, the data portion following the servo information is divided into a plurality.

Further, according to the present invention, the read first
After forming a plurality of write / read signals based on the servo information in the first sector based on the servo information in the second sector, if the servo information in the second sector cannot be read, Based on the servo information of the first sector, a write / read control signal for a data portion in the second sector is formed.

[0010]

According to the present invention, since a plurality of write / read control signals are formed and output at different timings based on servo information, a plurality of data portions are formed by the plurality of write / read control signals. This makes it possible to realize a logical data length shorter than the physical data length, and to utilize the entire data area as an effective data area.

When the servo information in the second sector cannot be read, a write / read control signal for a data portion in the second sector is formed based on the servo information in the first sector. Therefore, data in the second sector can be read.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows a data sequence 13 read from a magnetic disk and an index formed from servo information Sn, S (n + 1), S (n + 2) and the like in the data sequence 13 in the magnetic disk drive of the present embodiment.・ Sector pulse signal ISP-A, ISP-
6B is a timing chart showing the ISP. here,
The data string 13 includes servo information Sn, S (n + 1), S
(N + 2) etc. and actual data IDn, ID (n + 1),
ID (n + 2) and the like. In FIG. 1, the index sector pulse signal ISP is formed by taking the logical sum of the index sector pulse signals ISP-A and ISP-B.

FIG. 2 is a block diagram showing one embodiment of the magnetic disk drive of the present invention. First, the data reading operation will be described. In FIG. 2, data 13 is stored on a magnetic disk 10. Then, the data 13 is read out via the head 11 attached to the arm 12 and input to the readout circuit 15 via the read / write amplifier 14. The data 13 input to the readout circuit 15 is separated into servo information S and a data string ID.
Is input to the control logic circuit 16, and the data string ID is directly input to the serial / parallel converter 17. The control logic circuit 14 creates an index / sector pulse signal ISP as a base point for demodulating the data string ID in accordance with the input servo information S, and generates the serial pulse converter 1
7 is output. The serial / parallel converter 17 demodulates the data string ID based on the input index / sector pulse signal ISP. In the control logic circuit 16, an index / sector pulse signal ISP-A which can be easily created from the servo information S is first generated. In the prior art, as shown in FIG.
Since the data demodulation processing was performed using only the sector pulse signal ISP-A as the index / sector pulse signal ISP, the illustrated data strings IDn and ID (n +
One physical data, such as 1) and ID (n + 2), cannot be divided into a plurality of logical data. However, in the present embodiment, the index / sector pulse signal I
After the transmission of SP-A, a new index / sector pulse signal ISP-B is further provided inside the control logic circuit 16.
And an index / sector pulse signal ISP-A
And the OR output of the index sector pulse signal ISP-B and the index sector pulse signal ISP,
It is output to the serial / parallel converter 17. Thereby, one data area of the data string 13 can be subdivided into two logical data areas. Serial-to-parallel converter 1
7 converts the input data into parallel data,
Output as D read data. Therefore, it is possible to take a logical data length in a unit shorter than the physical data length.

Next, the write operation of the data string 13 will be described. The input WD write data is converted into a serial data string by a parallel / serial converter 18 and input to a write circuit 19. Here, the conversion operation is performed with the index / sector pulse signal ISP (ISP-A, ISP-B) output from the control logic circuit 16 as a starting point. The WD write data thus converted into serial data is recorded on the magnetic disk 10 via the write circuit 19, the read / write amplifier 14, and the head 11. Therefore, the data string 13 recorded on the magnetic disk 10 is composed of the index / sector pulse signal I
It is recorded in synchronization with the SP (ISP-A, ISP-B).

FIG. 3 shows an index / sector signal ISP- based on the servo information S of the read data string 13.
5A is a time chart illustrating an operation of generating ISP-B. As shown, the servo information S includes an AM 19 indicating the head of the servo section, an MK section 20 indicating the distinction between the index signal and the sector signal, and a GRAY section 21 indicating the position information of the head 11. First, the internal counter in the control logic circuit 16 is cleared by detecting the AM signal 19 from the data string 13, and thereafter, the counter continues to count up as time elapses. The count value is equal to the index / sector pulse signal ISP-
An index / sector pulse signal ISP-A is generated at a timing coincident with the generation position of A. The count-up continues even after the generation of the index / sector pulse signal ISP-A, and when the count value reaches a predetermined value, the index / sector pulse signal ISP-B is generated.

FIG. 4 is a block diagram showing an example of the read circuit 15 and the control logic circuit 16 shown in FIG. 2, and FIG. 5 is a time chart showing an example of the operation of the circuit shown in FIG. As shown in the figure, the data string 13 is input to the servo section detection circuit 25, and the head of the servo information S is detected. next,
The servo section detection circuit 25 issues an initialization signal 24 to a counter 26 that counts clock pulses 23 output from a high-precision crystal oscillator (not shown). The counter 26 that counts the clock pulse 23 output from the crystal oscillator is reset by the clear signal 24 and starts counting. The count values 26a, 26b, 26c to 26n output from the counter 26 are input to the comparison logic circuits 27, 28, 29. The comparison logic circuits 27, 28, and 29 determine whether or not the preset value matches the input count values 26a, 26b, 26c to 26n, and output a pulse signal only when the values match. . That is, the comparison logic circuit 27 determines whether or not the count value of the counter 26 is equal to the output time T1 of the first index / sector pulse signal ISP-A.
SP-A is output. Further, when the comparison logic circuit 28 detects that the time has elapsed and the count value of the counter 26 has become equal to the output time T2 of the second index / sector pulse signal ISP-B, the comparison logic circuit 28 detects It outputs a sector pulse signal ISP-B. This 2
Two index sector pulse signals ISP-A, IS
By taking the logical sum of P-B, an index / sector pulse signal ISP can be created.

Next, data reading when servo information cannot be read due to scratches on the magnetic disk will be described with reference to FIGS. 3, 4 and 6. FIG. In FIG. 6, a first index sector pulse signal ISP-An and a second index sector pulse signal ISP-Bn are output according to the servo information Sn.
Even after that, the counter 26 does not stop,
Continue counting.

The correctly read servo information Sn
If the next servo information S (n + 1) cannot be read, the servo section detection circuit 25 shown in FIG. 4 does not operate properly. Therefore, the servo section detection circuit 25 sends the counter 2
6, the reset signal 24 is not output, and the counter 2
6 continues counting (see FIG. 3). As a result, the third index / sector pulse signal ISP-C is output from the comparison logic circuit 29 after the elapse of the time T3 shown in FIG. Index / sector pulse signal ISP-C
Is the index sector pulse signal ISP-A, IS
Like the P-B, it is input to the OR circuit 31 and becomes an index / sector pulse signal ISP. When the index / sector pulse signal ISP-C is output, the counter 2
By controlling the count value of 6 to be the value of T1, the generation logic of the index / sector pulse signal ISP-B generated at the count value T2 can be simplified.

In the above embodiment, the case where the data area is divided into two parts has been described as an example. However, the present invention is not limited to this. Is also applicable.

According to this embodiment, the following effects can be obtained. That is, by generating an index / sector pulse signal in the middle of the data area, a data area having a logical data length shorter than the physical data length can be secured. Further, when a request to reduce the logical data length to 1/2 or less of the physical data length occurs, in the prior art, it cannot be realized unless the total storage capacity is reduced to 1/2 or less. This can be realized without reducing the storage capacity.

Further, even when the servo information cannot be read, the counter for realizing the data read / write operation and the counter for generating the index / sector pulse signal can be shared, and can be realized with a simple circuit configuration. effective.

[0022]

Since the present invention is configured as described above, it has the following effects.

It is possible to provide a magnetic disk drive capable of realizing a logical data length shorter than the physical data length and utilizing a surplus physical data area as an effective data area at that time.

Further, the present invention provides a magnetic disk drive capable of reading out data recorded in a data area when the servo area cannot be read due to a scratch on a disk surface or the like. Can be.

[Brief description of the drawings]

FIG. 1 is a timing chart showing a data train read from a magnetic disk and an index / sector pulse signal formed from servo information in the data train.

FIG. 2 is a block diagram showing one embodiment of the magnetic disk drive of the present invention.

FIG. 3 is a time chart showing an operation of generating two index / sector signals based on servo information of a read data string.

FIG. 4 is a block diagram showing an example of a read circuit and a control logic circuit shown in FIG.

5 is a time chart showing an example of the operation of the circuit shown in FIG.

6 is a time chart showing an example of the operation of the circuit shown in FIG.

FIG. 7 is a timing chart showing an index / sector pulse signal formed by a conventional technique from a data sequence read from a magnetic disk and servo information in the data sequence.

[Explanation of symbols]

10: magnetic disk, 11: head, 13: data train,
14: read / write amplifier, 15: read circuit, 16: control logic circuit, 17: serial / parallel converter, 18: serial / parallel converter, 19: write circuit, 25: servo unit, 26: counter, 27: comparison logic Circuit, 28: comparison logic circuit, 29: comparison logic circuit, ISP-A: index sector pulse signal, ISP-B: index
Sector pulse signal, ISP: index / sector pulse signal.

Continuation of the front page (56) References JP-A-4-289560 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 20/10

Claims (3)

(57) [Claims] A plurality of servo information recorded on a magnetic disk are read, and a write / read control signal is generated based on the read servo information. In a data writing / reading method for a magnetic disk device that performs write / read control based on the servo information, a plurality of write / read control signals are generated at different timings based on each servo information, and the plurality of write / read control signals are generated.
Based on the signal for reading control, Servo information and the next servo
A data writing / reading method for a magnetic disk drive, wherein a data area between information and information is divided into two or more . 2. A method for reading a plurality of servo information recorded on a magnetic disk, generating a write / read control signal based on the read servo information, and generating a write / read control signal based on the read servo information. A function of generating a plurality of write / read control signals at different timings based on each servo information in a magnetic disk drive that performs write / read control based on the servo information; A magnetic disk drive having a function of writing or reading data so as to divide a data area between one piece of servo information and the next piece of servo information into two or more pieces of data based on the information. 3. The magnetic disk drive according to claim 2, wherein a data area between said one servo information and the next servo information has two sectors.