JPS61199276A - Disc control system - Google Patents

Abstract

PURPOSE:To perform an accurate address collation even for specific data by detecting an address field by index pulse counting if it cannot be detected with the prescribed collation in a disc device of the sector blocking system. CONSTITUTION:A sequencer 13 is started by a microprocessor 18, and an AND gate 14 is opened by a synchronizing pattern detecting circuit 12. Read data from a receiver 10 which passes a serial-parallel conversion shift register 11 is supplied to a CRC check circuit 16, and CRC check of the address field is performed. If the check code coincides in this check but does not coincide in the next check, the processor 18 discriminates the former field as a normal address field. Meanwhile, if data of a data field coincides with the check code of the address field and the address field is not detected throughout one track, the processor 18 collates accurately the address field by the counted value of sector pulses form the sequencer 13 which passes a buffer 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a disk control method, for example, to a magnetic disk control method.

(Background of the Invention) In a magnetic disk device, a method is known in which data is blocked in multiple pieces and addressed to improve data usage efficiency (Japanese Patent Laid-Open No. 58-91512).
.

Address verification in a conventional disk device involves reading ID information by detecting a sector pulse signal when reading or writing is activated by a command, and comparing the address with a target sector given at the same time as the command activation or in advance. Find the target sector location.

As shown in FIG. 4, in the magnetic disk device, a head 6 attached to a head arm 2 reads and writes data to a sector 103 obtained by dividing a track 101 into a rotating recording medium disk 1. .

The data field (D
ATA). The address field (ID) is information indicating the location of the sector, and G12, . . .
This field is required for field verification, etc.

Further, there is one index 102 on the track indicating the starting point of the track.

In a magnetic disk drive that uses a sector pro-ragging method in which data fields are grouped into multiple areas and addresses are displayed using one ID field, as shown in Figure 4, the information read by detecting a sector pulse signal is used as ID information. There may be cases where it is general data instead of data. In such a case, the verification of the check code included in the ID information along with the address information generally fails, and the data is read until the next sector pulse signal is generated and the check code is verified. repeat. However, if the data field happens to contain a pattern that matches the check code as an address field, an address will be verified.

(Object of the Invention) An object of the present invention is to provide a disk device that uses a sector blocking method, and is capable of performing address verification even if the data field stores data whose check code matches that of the address field. The objective is to provide a control method.

(Summary of the Invention) The present invention calculates a sector pulse from an index pulse when an address field that satisfies the conditions cannot be detected even after performing address verification for all sectors of one track. The data is read out, and the target sector position is searched for using that data as an address field.

Examples of the invention] An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 3 shows an example of the data format within the disk device. In this example, one track of data is SR1, 2,...
, N, and each sector block is divided into N sector blocks denoted by DATAI, 2. This is an example in which m data fields indicated by rn are blocked and a CRC code is used as a check code. The index pulse indicates the starting point of the track and is located at one location on the track, and the sector pulse is located at each data field except for the first data field DATA I. sector block 1
03 is displayed as an address using one ID. ID is 8YNC pattern (SYN) indicating the beginning of address information.
C), -t lid block address (SI) A), head address (HA), cylinder address (CA) and 5
CRC check code (IDCR) from YNC to CA
FIG. 1 shows the configuration of a disk control mechanism which is an embodiment of the present invention, and FIG. 2 shows its processing flow.

Serial data from the disk device is received by a receiver 10 via a line 20, and converted from serial data to parallel data by a shift register 11. When the command is activated, the microprocessor 18 activates the sequencer 13.
Start. When the sequencer 13 receives the first sector pulse 1iA 21 that arrives thereafter (step 101), it activates the 5YNC pattern detection circuit 12.

Also, the AND gate 15 is opened and read data is stored in the data buffer 17. 5YNC pattern detection circuit 12
When detecting a 5YNC pattern, it opens the AND gate 14 and inputs the output data of the shift register 11 to the CRC check circuit 16. These series of processes are step 1
02 de Ruru. The CRC check circuit 16 transmits the completion and result of the CRC check to the microprocessor 18 (
Step 103). Since reading is performed from the sector pulse after activation, as can be seen from FIG. 6, there are cases of address fields and data fields. If data reading is activated from the address field and there is no abnormality in the read data, the CRC check for the address field will match. However, if a microprocessor is activated to read data from the data field, the CRC check as the address field will generally not match. However, if by chance data that matches the CRC check as an address field is stored at the beginning of a data field, the beginning of the data field will be mistakenly recognized as an address field. If the check codes match, address verification is performed assuming that it is an address field (step 104). This is done by sending the data in data buffer 17 to microprocessor 18. If the address is normal, the next sector pulse will be detected (step 106).
, reads the data of the next field on the disk (step 107), and checks whether the check codes match (step 108). If the check codes do not match, it is determined that the part read the second time was a data field and the previous field was an address field.

In other words, in order to prevent the above-mentioned misidentification, data is read from the next sector pulse and C is used as an address field.
Only when the RC codes do not match, it is determined that the previous address verification is correct and the target sector position is calculated.

In this case, if data with matching CRC check codes is stored in the data fields of all sector blocks, the above address verification becomes impossible. Therefore, according to the illustrated conditions of steps 103, 105, and 108, the process proceeds to step 110. That is, if the check codes do not match in step 105, step 10
Since the part read in step 2 was not an address field, step 110. Steps 101 and 102 are repeated until a matching portion is reached within one track. Step 1
05. The same applies to step 108.

If an address field that satisfies the above-mentioned conditions is not detected even after searching for one track, the process proceeds to steps 111 and 112, where the number of sector pulses after the index pulse is detected is counted, and the beginning of the target sector block is counted. Detect and read the data of that part (
Step 113). And if the check code of that field matches in step 114 (step 114)
, the address field is checked (step 115), and if it is found to be normal, it is determined that the target sector is found. If steps 114 and 116 are not satisfied, the process moves to error processing.

In this way, data is further read from the next sector pulse, and only when the CRC code as an address field is found to be inconsistent, it is determined that the previous address verification is correct, and the target sector position is calculated. If data with matching CRC check codes is stored in the data fields of all sector blocks, the above address verification becomes impossible. Therefore, the above address matching process is
If an address field that satisfies the above conditions is not detected even after performing the process for several tracks, the data on the disk is read from the sector pulse of the sector immediately after the index pulse, and the target sector position is calculated using that data as ID information. .

〔Effect of the invention〕

According to the present invention, it is possible to provide an address matching method that makes it possible to calculate a target sector for a track even if data whose check codes match the address fields coincidentally exists in all data fields.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a magnetic disk control mechanism which is an embodiment of the present invention, Fig. 2 is a diagram showing sector blocking consisting of m data fields, and Fig. 3 is a diagram illustrating an embodiment of the present invention. FIG. 4, which is a diagram showing a processing flow, is a diagram showing a sector blocking type magnetic disk device. 101... Track, 102... Index position, 103... Sector block, 10... Receiver,
11... Shift register, 12... 5YNC detection circuit, 13... Sequencer, 16... CRC check circuit, 17... Data buffer, 18... Microprocessor.

Claims (1)

[Claims] This is a fixed data length sector method in which one track is divided into equal parts by a sector pulse signal, and data fields of a predetermined length are grouped into multiple areas, and one address field is used to divide the sector into multiple areas. In a disk device that uses a sector blocking method that displays block addresses, only when the check code of the field processed as an address field matches and the check code of the immediately following field does not match, the previous field is considered to be a normal address field. At the same time, 1
A disk control method characterized in that, when a normal address field cannot be detected within a track, the beginning of a sector block is detected by counting the number of sector pulses from an index pulse.