JPH01105364A - Defect detection system for magnetic disk medium - Google Patents

Abstract

PURPOSE:To reduce the defect undetectible area of a medium by comparing test data with writing/reading data with plural track formats with different selector length for the same track. CONSTITUTION:A writing means 2 writes the test data to the track having a magnetic disk medium 1 using a format A, a reading means 3 reads the data written by using the format A, a comparing means 4 compares the read data with the written data, and when a different part exists, it is made into a medium defect detected by the format A. Next, a writing means 5 writes the test data to the medium 1 using a format B, a reading means 6 reads the data written by using the format B, a comparing means 7 compares the read data with the written data, and the different part is detected as the medium defect. A deciding means 8 totals the respective medium defects, one of the medium defects at the same position detected with the both formats is eliminated, and the residual one is made into the final medium defect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention provides a magnetic disk medium defect detection method for detecting defects in a magnetic disk medium by comparing data written to the magnetic disk and data read from the magnetic disk. Regarding.

[Prior Art] Conventionally, a method has been used to detect defects in a magnetic disk medium by writing data to a magnetic disk medium according to a predetermined format, reading the data, and comparing the written data and the read data. That is, the position of a defect in the magnetic disk medium is known by detecting the write position of data where write data and read data do not match.

Figure 3 is a diagram showing an example of a write/read track format used in the conventional defect detection method for magnetic disk media.The upper figure shows the format of the entire track, and the lower figure shows the format within one sector. ing. In the figure, (10) is the trunk, (11) is the truck (1
0), (12) is the index that becomes the track reference position between the first sector 0 and the last sector n, and (13) is the index between index (12) and the first sector O. Gap 0, where information is not written between (
14) is the gap 4 between the last sector n and the index (12), (15) is the first gap 1 in each sector (11), and (16) is the index data part ( (hereinafter referred to as the ID part), (17) is the gap 2 in each sector (11), (18) is the gap 2 in each sector (11)
), the data part (19) is the last gap 3 in each sector (11). Above gap (13) (14)
(15) (17) and (19) are areas that are absolutely necessary due to errors and fluctuations in the number of rotations of the medium, areas for controller operation, and the like.

Write test data to each sector (11) in the above format, read it, and compare the written data and read data for each sector. If they match, the magnetic disk medium is free from defects. If there is a mismatch, it is found that there is a defect in the position of the magnetic disk medium where the mismatched sector is written. However, the gap (13) in the write track format (10) (
14) (15) Even if there is a defect in the positions (17) and (19), no data will be written to that position, so the defect will not be detected.

[Problems to be Solved by the Invention] Since the conventional defect detection method for magnetic disk media is performed as described above, there is a gap (13) on the track format (10) where data cannot be written or read.
(14) (15) (17) and (19) exist,
There is a problem in that defects cannot be detected in a relatively wide area of the magnetic disk medium.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a defect detection method for a magnetic disk medium that can significantly reduce the area in which defects cannot be detected on the medium.

[Means for Solving the Problems] The magnetic disk medium defect detection method according to the present invention is capable of writing and reading test data and comparing written and read data on the same track in a plurality of track formats with different sector lengths. This is what I decided to do.

[Function] The magnetic disk medium defect detection method according to the present invention is as follows:
Because data is written to and read from the same track using multiple track formats with different sector lengths, the gap position in each format may shift, and even if there is a defect in the gear position in one format, it will not be corrected in other formats. Detection is possible by comparing written and read data at the location.

[Example code] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the format used in this embodiment. In the figure, (1) is a magnetic disk medium, (2) is a format A writing means for writing test data on the magnetic disk medium (1) using track format A having sectors with a short sector length, and (3) is a format A writing means for writing test data on the magnetic disk medium (1). (4) is a format A read/write data comparing means that compares the data written and read in format A to detect defects in the medium; (5) is a format A read/write data comparing means for comparing data written and read in format A; Magnetic disk medium (1) with track format B (20) with sectors
Format B writing means for writing test data into (
6) is a format B reading means for reading this written data, and (7) is a format B reading means for comparing data written and read in format B to detect defects in the medium.
The write/read data comparison means (8) is a defect on the medium excluding one of the defects detected in both formats at the same position on the medium from the total of defects detected by both write/read data comparison means (4) and (7). (1o) is a format A track, (11)
) is the (n+1) sectors in the format track (10), (12) is the index of format A,
(13) is format A gap 01 (14) is format A gap 4, (15) is format A
Gap 1, (16) is the ID part of format A, (
17) is gap 2 of format A, (18) is the data section of format A, (19) is gap 3 of format A, (20) is track of format B, (2
1) is a sector length (m +
1) sectors, (22) is the index of format B, (23) is the gap 01 of format B (24
) is gap 4 of format B, (25) is gap 1 of format B, (26) is ID of format B
part, (27) is gap 2 of format B, (28)
is the data portion of format B, and (29) is gap 3 of format B.

In order to detect medium defects in the above configuration, first, in means (2) test data is written in a certain track of the magnetic disk medium (1) in format A, and in means (3).
) reads the data written in this format A, and compares the read data with the written data in means (4), and if there is a difference, the data is written in format A.
This is a media defect that could be detected. Here, gap O (13), gap 4 (14) in track (10) of format A, gap 1 (
15), gap 2 (17) and gap 3 (1
The medium defect at position 9) cannot be detected.

Next, means (5) writes test data in format B on the same track of the magnetic disk medium (1), means (6) reads out the data written in format B, and means (7) The read data and the written data are compared, and if there is any difference, it is a medium defect detected by format B. Again, gap O (23), gap 4 (24), and each sector (21) in track (20) of format B.
Media defects at the positions of Gap 1 (25), Gap 2 (27) and Gap 3 (29) cannot be detected.

Next, in means (8), the medium defects detected in format A in means (4) and the medium defects detected in format B in means (7) are summed, and One of the media defects is removed and considered as the final media defect.

In this way, the gap 0 (13) in the format Ha track (1o) and the format B track (20)
(23), gap 4 (14), except for part of (24) and gap 1 (15) (25) in the first sector,
One gap area overlaps the medium defect detectable area of the other, making it possible to detect medium defects in the entire remaining area.

Note that the formats used in the above embodiments are merely examples, and are not necessarily limited to these, and not only two types of formats but three or more types of formats may be combined.

[Effects of the Invention] As described above, according to the present invention, writing/reading and writing/reading data are performed for the same track in formats with different sector lengths.
The area where defects cannot be detected on the medium is drastically reduced, and
The effect is that the same hardware, firmware, and software as those used for writing and reading general data can be used by simply adding software.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the format used in this embodiment, and FIG. 3 is a writing diagram used in a conventional defect detection method for magnetic disk media. FIG. 3 is a diagram showing an example of a read track format. In the figure, (1) is a magnetic disk medium, and (2) is a disk medium.
8~ Ormat A? (3) is Format A reading means, (4) is Format A write/read data comparison means, (5) is Format B writing means, (6) is Format B continuous output means, (7) is Format B writing. Read data comparison means, (8) medium defect determination means, (10) format A track, (11) format A sector, (13) (14) (15)
(17) and (19) are the gaps of format A, (
20) is a format B track, (21) is a format B sector, (23) (24) (25) (
27) and (29) are format B gaps. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] In a defect detection method for magnetic disk media, which detects defects in magnetic disk media by comparing the data written to the magnetic disk and the data read from it, in which one track is divided into multiple sectors and data is written and read for each sector, the same A defect detection method for a magnetic disk medium, characterized in that writing and reading data and comparing written and read data are performed for tracks in different sector length formats.