JPS60212873A - Method for measuring settling time of magnetic disk device - Google Patents

Abstract

PURPOSE:To obtain a correct settling time, by finding the maximum delay time capable of reading out without any error by accessing a target sector, and subtracting the delay time from a prescribed time from a reference point on the one round of a track to the target sector on another sector. CONSTITUTION:Formats for inspection are respectively performed on tracks 36- 38. A target sector which leads data is the sector 5 of the track 37 and accessing of the sector 5 is performed from the adjacent tracks 36 and 38. When the target sector is accessed in successively shortening a delay time from a reference point A, and in case the delay time at the moment when an error finally occurs is 27ms, the settling time goes to a value obtained by subtracting the 27ms from the time 45ms which is the time from the reference point A to the most leading edge of the sector 5. Therefore, practically accurate settling time measurement can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for determining the stabilization time, that is, the settling time, after a head moves on a track in a magnetic disk device such as a fixed or flexible (hereinafter referred to as floppy) disk drive device. It is related to the measurement method.

Conventional configuration and its problems The settling time is conventionally defined using an analog expression, and FIG. 1 shows this.

As mentioned above, the cell ring time is the minimum waiting time during which the head moves along the track and after reaching the target track, the vibration of the head becomes stable and data can be read without error. Example of figure (d, track 38 to 3
9 of the playback waveform, including the step time when moving to 9.
The time it takes to settle down to 0% is defined as 7 hours.

However, definition using this method is not realistic. This is because the simple amplitude of the reproduced waveform and the data read limit do not necessarily have a certain consistency, and the data modulation method, data content, or degree of noise superimposition of the reproduced waveform (
This is because it varies slightly depending on factors such as the SN ratio). Therefore,
Sometimes even a few changes in the reproduced waveform can cause an error to occur.
In some cases, data may be read without error even if the arc width is reduced to 50% or less. Therefore, it is appropriate to determine the settling time in such a case by confirming it with data, and there is no doubt that it is a more realistic method.

OBJECTS OF THE INVENTION The purpose of the present invention is to inspect and measure the settling time of a magnetic disk drive by checking the read waveform as the final read signal in the disk drive, instead of looking at the reproduced waveform, that is, the analog quantity, as in the conventional example described above. The settling time is defined by digital judgment as to whether data can be read without error or not, and the object is to provide a realistic measurement means suitable for actual use.

Structure of the Invention In order to achieve the above object, the present invention provides a reference point during one round of a track and a target sector on another track separated by a predetermined time from the reference point.

- Explanation of an embodiment in which the settling time is the time obtained by subtracting the maximum delay time that can be read out from the predetermined time.Hereinafter, embodiments of the present invention will be described. .

FIG. 2 is a model diagram related to the measurement of track 36.3 to explain an embodiment of the present invention.
7.38 are each formatted for inspection. (Format contents are MFM, 256B/163
．． DATAB6. The target sector for reading DBH) data is sector "5" of track 37, and access is made from adjacent tracks 36 and 38. The reason for doing this from both directions is to prepare for the case where the head carriage has some kind of directional dependence.As a result, the larger of the two is taken.
If there is a delay of 1 hour from the Eth point), the settling time is the time from reference point A to the beginning of sector "5" of 46m5 (number of data 1
．． 407X3271s 245m5) to the above 27m
5 is subtracted (however, the step time is also included). As mentioned above, the error occurs due to the damped vibration of the head carriage after track movement, and the error occurs in sector "5".
This can be confirmed by ■・D error and data verification error. 1, the reason why the target sector is set to [5] is because of the relationship between the maximum drawing time at the delay time of zero, and if it is not so necessary, the target sector is set to ``4J'' or ``3'' ( ' You can also do it.

Effects of the Invention As is clear from the above explanation, according to the present invention, settling time is defined not by the amplitude stability of the reproduced waveform, which has been conventionally used, but by a practical method based on read data errors. Because of this, more realistic and accurate measurements can be achieved.

[Brief explanation of the drawing]

Figure 1 is conventionally used. A waveform showing a method of measuring settling time using an IJ raw waveform) and a second waveform are model diagrams showing a predetermining method based on read data according to the present invention. 36, 37, 38 tracks. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure Procedures Amendment Book Showa IJ59i・-9ノ''ノ2〔　Article 4'l Indication 1988 1r;i' ``Application No. 69365 Bow 2 Name of Invention Magnetic Tisf Device: Okerede I・Ginoge Time Z3.
The person who performs the fixed method 3 uramasa];・：＋こ・;□・−ζ
7. Kadoma City, Osaka Prefecture Bold 1')] True 1.006 Address Name
1. (562) (fairness 'a ai +'l business
Chair, Ceremony and Soil:' Name: Yamashita Yuhiko 4 Agent: Address: 571 1. ; Osaka 11 "Kadoma Major'; 1°] Only 1006
Address: Matsushita Electric Industrial Company, 5, 7. "elephant

Claims (1)

[Claims] A reference point during one track round and a target sector on another track that is a predetermined time away from the reference point are set, and after a certain delay time has elapsed from the reference point, the target sector is accessed without error. A settling time method for a magnetic disk drive, characterized in that the maximum delay time that can be read is determined, and a time obtained by subtracting that value from the predetermined time is set as a settling time.