JPS63308772A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To contrive the improvement of the bit error without lowering the access time by adding an error correction code to an ID area or a data area of each sector classified into a recording area and a sector of a magnetic disk so as to attain error correction at an error correction circuit. CONSTITUTION:A magnetic disk controller 1 of a magnetic recording and reproducing device is placed between a host system 2 and a magnetic disk device 3 to attain recording or read control to the device 3. A microprocessor 12 of the controller 1 controls each section, the recording area of the disk is classified into plural sectors, and the classified sector each is classified into an ID area and a data area, an error correction code is added to the ID area and the data area and the result is recorded to a different sector. Moreover, a control circuit 17 of the controller 1 is provided with an ID area error correction circuit 14, a data area error correction circuit 15 and a data area error correction circuit 16 or the like to improve the bit error rate without lowering the access time.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetic disk that divides a recording area of a magnetic disk into sectors, and further divides each sector into an area and a data area for recording. The present invention relates to a recording/reproducing device, and particularly to a magnetic recording/reproducing device equipped with an error correction circuit.

(Prior Art) Conventionally, in a magnetic recording/reproducing device equipped with an error correction circuit, the error rate (erroneous reading rate) of data read from the magnetic recording/reproducing device is 10'''S (number of error bits/
The error correction circuit is used to keep the error rate of data to the host system below 10".The error correction circuit is used extremely rarely and the time required for error correction is limited. It could be assumed that this does not affect the average access time. By the way, when considering the ability of the error correction circuit, the error rate of data read from a magnetic disk drive is actually less than 10-1. Further increases are possible.

When the error rate is increased, bit errors can be tolerated by the difference in the error rate, so the recording density of the magnetic disk can be improved by the increase in the so-called phase margin.
In other words, it is possible to increase the storage capacity.

In this way, in magnetic recording and reproducing devices that increase the error rate, improve the phase margin, and increase the density, and ensure the reliability of information through error correction, the frequency of use of the error correction circuit increases, and the amount of time required for error correction increases. Time could no longer be ignored and access time was reduced.

Therefore, a recording format has been devised in which the corresponding ID area and data area are physically located in different sectors as shown in FIG. Each divided sector R3N0, P
SN 1 , PSN 2 -... are IO areas IDO, ID3 . . . as shown in FIG. ID6-... and data area DATA5. DATAO.

DATA3... As shown in the figure (d), the ID area contains information PLL-5YNC for phase synchronization of the PLL (phase synchronized circuit), AMT indicating the beginning of the ID area, and defective sectors. Or FLAG indicating an alternative sector
, PCNH, PCNL indicating the data cylinder number,
P)IN indicating the physical head number, ISN indicating the logical ID area sector number, DSN indicating the physical sector number of the data area corresponding to the ID area, I
Redundant bit E for error detection and correction of information in area D
ID-P indicating the boundary between CC1 and ID area and data area
It is composed of AD. Also, the data area is PLL-5
YNC, AMD indicating the beginning of the data area, recording data D
It consists of ATA, an error correction code ECC1 for correcting errors occurring in the data area, and DATA-PAD provided between the data area and the next sector area.

Recording or reproduction in the data area of a magnetic disk having such a recording format is performed after first confirming the information in the ID area of each sector. Errors occurring in the information in the ID area are detected by comparing the error correction code created using the read ID area information with the error correction code recorded in excess. This error detection is performed at high speed, but if an error is detected, a certain amount of error correction processing time is required, and the information within this time cannot be read. Similarly, information loss occurs. Specifically, when recording or reproducing an entire track using the recording format shown in FIG. 3(c), (
Here, error correction of information in the ID area must be completed before reading information in the next ID area, and error correction in information in the data area must be completed before reading information in the next data area. Make it. ) IDO in one rotation of the disk
,DATAO.

IDI, DATAI, ID2. It can only process the information of DATA2 and ID3. DATA3. ID4. D
ATA4. Processing of ID5 information.

DATA5 at the 3rd rotation. ID6. DATA6. ID7.
Information on DATA7 was being processed. In other words, it took three revolutions of the disk to record or reproduce one track.

(Problems to be Solved by the Invention) The present invention improves the problem that access time becomes longer when the error rate of a magnetic recording/reproducing device using an error correction circuit is increased as described above. An object of the present invention is to provide a magnetic recording/reproducing device that prevents a decrease in access time while improving the performance.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a magnetic recording method in which a recording area of a magnetic disk is divided into a plurality of sectors, and each sector is further divided into an area and a data area for recording. And an error correction code is added to the data area. The error correction circuits for error correction are separately provided with m and n circuits for the ID area and the data area, respectively. The error correction circuit for the ID area can complete the error correction process before starting to read the information in the ID area of the sector m sectors ahead from the sector in which the ID error was detected, and each time it detects the ID area, it reads m IDs. The area error correction circuits are sequentially switched and used.

Similarly, the error correction circuit for the data area can complete the error correction process before starting to read the data area information of the sector n sectors ahead from the sector in which the DATA error was detected, and each time it detects the data area, n pieces of data are The area error correction circuits are sequentially switched and used. Further, the ID area and the data area corresponding thereto are not adjacent to each other, and the data area is physically arranged in m sectors from the sector where the ID area exists, so that the data area and the following ID area are arranged.
The recording format is formed by arranging the areas adjacent to each other.

(Function) In a magnetic recording/reproducing device in which only an error detection code is added to the ID area, if an IO bit error is detected, the device is forced to wait for the disk to rotate for a retry.

In the present invention, since an error correction code is also added to the ID area, even if a bit error is detected in the information in the ID area, error correction is performed and there is no need to try again. In this case, if an error occurs in the information in the ID area, access to the data area is started while the error correction process is being performed, and the information in the data area is lost.

Therefore, in the present invention, m error correction circuits for information in the ID area and n error correction circuits for information in the data area are provided, and error correction in the ID area is performed for m pieces of ID ahead.
The error correction for the information in the data area is completed before the reading of the data area begins. Furthermore, the 1m ID area error correction circuits are sequentially switched and used each time an ID area is detected, and the n data area error correction circuits are also sequentially switched and used each time a data area is detected. As a result, even if error correction is performed in either the ID area or the data area, information can be read out without losing information or reducing access time during error correction processing. Next, when recording information, the information in the ID area is read, and when it is correct, the information is written in the data area corresponding to the ID area. If they are placed adjacent to each other in the same sector, access to the data area will start while error correction processing is being performed on the information in the ID area, and it will be necessary to wait for one rotation of the disk to write information. Therefore, in this invention, the ID area and data area are not adjacent to each other, and the ID area and data area are not adjacent to each other.
They are arranged at a distance slightly longer than the distance corresponding to the time required to complete the correction process using the error correction code of the area. As a result, even if error correction is performed in the In area, the corresponding data area is immediately accessed, and information can be recorded without waiting for the rotation of the disk.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a recording format of a magnetic disk according to an embodiment of the present invention. Here, a magnetic recording/reproducing apparatus is assumed that includes one error correction circuit for an ID area and two error correction circuits for a data area. FIG. 5A shows an index signal, which is a signal whose period corresponds to one revolution of the disk. The index pulse interval corresponds to the track length, and one track length is divided into a plurality of sectors. FIG. 4B shows sector pulses generated for each sector. FIG. 4(c) is a diagram showing the recording format, and FIG. 4(d) is an enlarged diagram of the recording format of each sector.

In the same figure (c), the ID area/IDO and the corresponding data area/DATAO are not located adjacent to each other in the same sector, but are interleaved in sectors PSNO and PSNI respectively.The distance between them will be described later. The distance is longer than the distance corresponding to the error correction processing time using the error correction code ECC in the ID area, but it is placed at a position as close as possible. However, the data area/DATAO and the ID area/IDI following it do not need to be interleaved and are arranged adjacent to each other. In addition, in the same figure (d), ID
An error correction code FCC and a data area sector number DSN are added to the area.

The error correction code ECC is similar to that recorded in the data area, and enables error correction, and is generated by the ID area error correction circuit 14. Data area sector number DS
N is information indicating the physical sector number of the data area corresponding to the ID area, and is necessary because the ID area and the data area corresponding to it are not located adjacent to each other.

According to such a recording format, for example, when reading out information in the data area DATA5 or recording information in the data area DATA5, ID5 is first searched and the data area sector number DSN of this ID5 is referred to and the corresponding response is performed. It is known that the physical sector number of the data area DATA5 is PSN6. If no error occurs in this ID5, from the DSN to the data area/DATA5
The read timing or write timing is determined. If an error occurs in ID5 and it is a correctable error, error correction processing is performed. At the end of this process, the magnetic head is immediately in front of ID6 and continues to take in the information of ID6. Here, if an error occurs in this ID6, error correction processing is performed by the IO area error correction circuit 14, but at the time this processing is completed, the magnetic head is immediately before ID7, and the information of DATA5 is processed by the same error correction circuit. It is impossible to process the data and is processed by the data area error correction circuit 15 or 16.

FIG. 2 is a diagram showing the configuration of a system for realizing the above method. A magnetic disk controller 1 is located between a host system 2 and a magnetic disk device 3, and controls recording or reading of information on the magnetic disk device 3. This magnetic disk controller 1 and host system 2 are connected via a host interface 11. A microprocessor 12 controls each part. The buffer memory 13 is a RAM that temporarily stores data to be recorded on the disk or data read from the disk. There are three error correction circuits, 14 for the ID area and 15 and 16 for the data area, each of which generates an error correction code ECC corresponding to the information recorded on the disk.
It has a function to correct any errors that occur in the data read from the disk. The control circuit 17 receives instructions from the microprocessor 12 or independently controls each block. Also, the recording/reproducing circuit 18
converts the parallel signal sent from the buffer memory 13 into a serial signal and outputs it as a write signal to the magnetic disk device 3, or converts the serial signal read from the magnetic disk device 3 into a parallel signal, Buffer memory 1 via control circuit 17
3 and error correction circuits 14, 15, and 16. The format generator 19 generates a recording format as shown in FIG. 1 mentioned above. A sequencer 20 controls formatting, recording, and reading sequences. Furthermore, the sector counter 21 generates a physical sector number from the index pulse and sector pulse from the magnetic disk drive 3 shown in FIG. 1CB)(b).

〔Effect of the invention〕

According to the present invention, even if an error occurs in either the ID area or the data area, the disk does not have to wait for one revolution, so even if the bit error rate increases, the access time does not decrease. Therefore, it can contribute to improving the storage capacity of magnetic disks.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the magnetic disk recording format according to the present invention, Fig. 2 is a block diagram showing an example of a system configuration for realizing the embodiment, and Fig. 3 is a diagram showing a conventional magnetic disk recording format. FIG. 3 is a diagram showing a format. DESCRIPTION OF SYMBOLS 1...Magnetic disk controller, 2...Host system, 3...Magnetic disk device 11...Host interface, 12...Microprocessor, 13...Buffer memory, 14...ID area error Correction circuit, 15...Data area error correction circuit (8), 16.
...Data area error correction circuit (b), 17...Control circuit, 18...Record/playback circuit, 19...Format generator, 20...Sequence, 21...
sector counter. Agent Patent Attorney Noriyuki Chika Yudo Mitsuyuki Matsuyama

Claims (1)

[Claims] The recording area of the magnetic disk is divided into a plurality of sectors, each sector is further divided into an area and a data area, and the ID
In a magnetic recording/reproducing device that employs a magnetic recording method in which an error correction code is added to an area and the data area, and the logically corresponding area and the data area are recorded in physically different sectors, information in the ID area is provided. I of the sector ahead of the sector where the error occurred (m is an integer greater than or equal to 1)
The error correction process can be completed before reading the information in the D area, and m number of I's can be sequentially switched for each ID area.
The error correction circuit for the D area can complete the error correction process before starting to read information in the data area of n sectors (n is an integer of 1 or more) ahead from the sector in which an error has occurred in the information in the data area. , n data area error correction circuits that can be switched sequentially for each data area.