KR19990065700A - Defect Sector Detection Method of Hard Disk Drive - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs

Defect Sector Detection Technology of Hard Disk Drive

I. The technical problem that the invention is trying to solve

It prevents errors caused by defect sectors in the user environment, and detects defect sectors on the disk and potentially sectors in a limited time.

All. Summary of the Solution of the Invention

In the process of detecting the defect sector of the disk side of the optical disc drive, the sectors near the defect sector found in the defect sector detection test are also recorded in the defect list, considering that the defects are likely to occur in the sectors near the defect sector. Defect sectors as well as sectors with possible defects are detected in advance in the manufacturing process of the magnetic disk storage device.

la. Important uses of the invention:

It is important for the detection of defect sectors in hard disk drives.

Description

Defect Sector Detection Method of Hard Disk Drive

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing process of a magnetic disk storage device using a magnetic disk, and more particularly, to a defect sector detection method for detecting a defect sector of a magnetic disk surface during a series of manufacturing processes so as not to be used in a user environment. .

A hard disk drive (HDD), which is a representative magnetic disk storage device widely used as an auxiliary memory device of a computer system, is a completed product through a series of manufacturing processes as shown in FIG. 1. Shipped.

1 is a flowchart illustrating a manufacturing process for explaining a series of manufacturing process steps of a general HDD, which is divided into six stages. Referring to FIG. 1, the first assembly (I) of the manufacturing process is a process of assembling a head disk assembly (HDA), which is a mechanical part of a HDD, in a clean room. The servo write process, which is the second stage (II) of the manufacturing process, is a process of recording a servo recording pattern for servo control of an actuator on a disk surface by a servo writer. The third step (III) of the manufacturing process, the function test, is the first test performed by combining the HDA made in the HDA assembly process and the PCBA made in the PCBA assembly process (usually performed after the HDA assembly process). Test that and PCBA work correctly. A basic test of about 20 to 25 minutes is then performed in combination with a specific test system. The burn-in process, which is the fourth stage (IV) of the manufacturing process, takes the longest time (normally 8 to 16 hours) of the HDD manufacturing process. It is a burn-in room without a separate test system. It runs in its own program (firmware) on the rack in. This burn-in process refers to a process of finding defects on a disk in advance so that a consumer can use the HDD normally, and preemptively avoiding the defects when using the drive. The final test process, which is the fifth step (VI) of the manufacturing process, is a process for checking whether the HDD set passed in the burn-in process is normally defectively processed. After the final test process, the HDD set is shipped as a finished product through the shipment inspection process, packaging and shipment process, which is the sixth step of the manufacturing process.

A defect sector detection test method performed in a burn-in process of a series of HDD manufacturing processes as described above will be described. The microprocessor, which controls the overall operation of the HDD to find the defect sectors on the disk surface, turns off the magnetic head of the actuator or changes the read / write channel parameter values. Light / lead tests are performed on the entire area of the disk surface by applying stress to the lead / light channels. In this write / read test process, a sector of a portion where an error of a write / read (defect occurs) is detected. The address of the sector where the defect has occurred is recorded in the defect list of the disk plane specific area (maintenance area), and then the HDD is provided to the real user without accessing the address of the defect sector in the user environment. do.

However, in the conventional defect sector detection test procedure described above, micro defects that have a small degree of defect and do not easily cause light / lead errors are not easily detected. These defects had a problem that the probability of generating an error if the HDD is degraded due to long use. In addition, in order to detect such defects completely, if the lead / light channel is subjected to more stress than the conventional light / lead test process, the entire area is tested, so much time is required, and thus the production cost is greatly increased.

Accordingly, an object of the present invention is to provide a method for preventing an error caused by a defect sector in a user environment by detecting the defect sectors as well as the defect sectors in the manufacturing process of the magnetic disk storage device.

It is an object of the present invention to provide a method capable of detecting defect sectors and potentially sectors on a disc within a limited short time.

In order to achieve the above object, the present invention focuses on the fact that there is a high probability that defects occur in the sectors near the defect sector in the process of detecting the defect sector on the disk surface. It is also characterized by recording on the defect list.

1 is a manufacturing process flow chart for explaining a series of manufacturing process steps of a typical hard disk drive

2 is a partial view of a disc showing an example of a configuration and format of a general information recording disc;

3 is a schematic overall block diagram of a hard disk drive to which an embodiment of the present invention is applied;

4 is a control flowchart of a microprocessor in a defect processing process according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, specific details such as specific components are shown, which are provided to help a more general understanding of the present invention, and it is understood that these specific details may be changed or changed within the scope of the present invention. It is self-evident to those of ordinary knowledge in Esau.

First, a hard disk drive to which the present invention is applied will be described. 1 is a schematic block diagram of a hard disk drive to which the present invention is applied. Referring to FIG. 1, the microprocessor 10 may include a programmable read only memory (PROM) 12 storing a predetermined control program and data of the microprocessor 10, and a static random access memory (SRAM). 14) to control the overall operation of the drive.

The head 16 is attached to one end of the actuator to rise to a predetermined height on the rotating disk 18, which is a recording medium, and is driven into and out of the disk 18 to write data to or read data from the disk 18 surface. The voice coil motor (VCM) 20 located at the other end of the actuator having the head 16 attached to one end drives the head 16 in response to the applied current level and direction.

The spindle motor 22 normally rotates the disk 18 mounted on the drive shaft in accordance with a control signal input from the motor driver 24. The VCM driver 26 is connected to the VCM 20 to control the driving of the VCM 20. The digital-to-analog converter (DAC) 28 is connected to the microprocessor 10 and the VCM driver 26, receives a digital control signal from the microprocessor 10, and converts the digital control signal into an analog signal and outputs the analog signal to the VCM driver 26.

The motor driver 24 is connected to the spindle motor 22 and the microprocessor 10 and controls the driving of the spindle motor 22 under the control of the microprocessor 10. The pre-amplifier 30 is connected to the head 16 to amplify and output the reproduced signal and output a signal to be recorded to the head 16.

The read / write channel circuit 32 is connected to the microprocessor 10, the preamplifier 30, and the disk data controller (DDC) 34, and receives the data to be recorded from the DDC 34 under the control of the microprocessor 10, encodes the data, and outputs the preamplifier 30 to the preamplifier 30. do. In addition, the read / write channel circuit 32 digitally converts the analog reproduction signal input from the preamplifier 30 and outputs the encoded read data (ERD).

An analog-to-digital converter (ADC) 36 is connected to the read / write channel circuit 32 to receive an analog servo reproduction signal, digitally converts it to PES, and outputs it to the microprocessor 10. The gate array 38 is connected to the read / write channel circuit 32 to receive an ERD signal and detects and outputs servo information such as gray codes in the servo region of the disc 18.

The DDC 34 has a sequencer that performs operations according to the microprograms downloaded from the microprocessor 10. The DDC 34 stores data received from an external data input device (e.g., a host computer) via a read / write channel circuit 32 and a preamplifier 30. Record on 18 or read data from disk 18 and send it to an external data input device. The DDC 34 also interfaces the host computer with the microprocessor 10. The DDC 34 also temporarily stores data transmitted between the host computer, the microprocessor 10 and the read / write channel circuit 32 in the buffer RAM 35.

The microprocessor 10, which controls the overall operation of the drive, controls the DDC 34 in response to read or write commands received from the host computer and controls track search and track following. The PROM 12 stores the above-described operating program of the microprocessor 10 and various setting values.

In the hard disk drive having the above-described configuration, the microprocessor 10 records the sectors in the vicinity of the defect sector found in the defect sector detection test in the defect list during the defect sector detection process of the disk surface according to the characteristics of the present invention. The operation will be described below in more detail with reference to the accompanying drawings.

3 is a partial view of a disc showing an example of a configuration and format of a general information recording disc, and not on an accurate scale. Referring to Figure 3 will be described a schematic configuration of the disk. The disk 18 can be roughly divided into a system area ①, a user data area ②, and a parking area ③.

The system area ① is also called a maintenance area, and stores various system information and information for maintenance of the hard disk drive, and is an area where general users are not allowed to access. User data area ② is an area for storing user data. The parking area ③ is an area used for parking the head 16 on the disk.

In more detail, the system area (hereinafter referred to as the maintenance area) is described in detail below. A manufacturer who manufactures a hard disk drive includes a unique number of the drive, related information during the manufacturing process, and a defect sector obtained by a defect sector test. Record information related to various systems, such as a list of defects in which the IP address is recorded, or SMART (Self Monitoring Analysis Reporting Technology) information, in the maintenance area ①. About four tracks are provided for this maintenance area.

The user data area ② occupies most of the disk surface, and data is recorded sector by sector on the track of the disk. The number of sectors per track is about 72, and each track has positional information or address on the disk. In FIG. 3, the sector format is shown by taking one track m as an example. The numbers 1, 2, etc. in sectors 1, 2, and the like shown in FIG. 3 do not indicate logical address order of sectors, but physical order.

On the other hand, the occurrence of defect sectors is usually due to physical causes such as scratches on the disk. When such defects are detected as the defect sectors as shown in FIG. Sectors Sector 2 and Sector 4 are likely to become Defect Sectors later, although they may not be detected as Defect Sectors. Accordingly, the present invention seeks to ensure the stability of recording / reproducing of data by treating adjacent sectors of the defect sector detected through the defect sector detection test as the defect sector as well.

Hereinafter, a process according to an embodiment of the present invention for a defect sector on a disk as described above will be described with reference to the accompanying drawings. 4 is a control flowchart of the microprocessor 10 of the defect processing process according to an embodiment of the present invention. First, the microprocessor 10 performs a defect sector detection test in step 40. The defect sector detection test in step 40 may be performed in the same manner as in the prior art. For example, in the detection test of the defect sector, the microprocessor 10 off-track servo-controls the head 12 and writes a specific data pattern for defect testing to a sector on the disk 18 through the read / write channel circuit 32. Then, the microprocessor 10 reads the recorded data pattern again, compares the read data with the recorded data, and considers the sector as a defect sector when an error occurs.

If the defect sector is detected, the microprocessor 10 determines that in step 42 and proceeds to step 44. In step 44, not only the detected defect sector but also the physically adjacent left and right sectors of the defect sector are recorded in the defect list of the maintenance area? As shown in FIG. Thereafter, the process proceeds to step 46 to check whether all sectors on the disk have been checked. If not all sectors have been checked, the process returns to step 40 and the process is repeated to perform the defect check on all sectors.

Although the process as shown in FIG. 4 is shown to be performed only on one data recording surface of the disc 18. It can be performed on the data recording surface of all disks in the drive.

In addition, in the above-described exemplary embodiment, when one defect sector is detected during the detection test of the defect sector, the neighbor sector is also recorded in the defect list when the defect sector is recorded in the defect list of the defect sector. Various changes or conversions may be made without departing from the scope of the present invention, such that the adjacent sectors of the defect sector recorded in the defect list may be further recorded by referring to only the defect list recorded after the conventional defect sector detection test is completed. Can be.

Therefore, the scope of the present invention should not be defined by the described embodiments, but should be defined by the equivalents of the claims of the present invention.

As described above, the present invention is focused on the fact that the defects are generated in the sectors near the defect sector in the process of detecting the defect sector on the disk surface, and the sectors near the defect sector found in the defect sector detection test are also determined by the defect list. Detecting defects in the manufacturing environment of the magnetic disk storage device as well as possible defects in the manufacturing process of the magnetic disk storage device, thereby preventing errors caused by the defect sectors in the user environment, and defect sectors and defects on the disk within a limited short time. There is an advantage in that it is possible to detect possible sectors.

Claims (3)

In the defect sector detection method of a hard disk drive, Performing a defect sector detection test to detect the defect sector; Recording position information of the detected defect sector in the defect list when detecting a defect sector; And recording position information of adjacent sectors on the same track of the detected defect sector in the defect list. 2. The method of claim 1, wherein adjacent sectors of the defect sectors are adjacent sectors one by one left and right of the defect sector. A method for detecting a defect sector of a hard disk drive in which a defect sector is detected and the position information of the defect sector is recorded as a defect list in a system area on a disk. And recording position information of physically adjacent tracks of the defect sector when recording the position information of the defect sector in the defect list.