Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
1998-06-03
2001-02-27
Sniezek, Andrew L. (Department: 2753)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S128000
Reexamination Certificate
active
06195221
ABSTRACT:
CLAIM OF PRIORITY
This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from an application entitled Preliminary Search Method For Minimizing Drop Down Phenomenon Of Hard Disk Drive earlier filed in the Korean Industrial Property Office on Jun. 3, 1997, and there duly assigned Ser. No. 22833/1997, a copy of which is annexed hereto.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a track search method of a hard disk drive, and more particularly to a preliminary track search method minimizing data loss of a hard disk drive.
2. Related Art
Computer systems are information handling systems that are utilized by many individuals and businesses today. A conventional computer system can be defined as a microcomputer that includes a central processing unit (CPU), a volatile memory, a non-volatile memory, a display monitor, a keyboard, a mouse, a floppy diskette drive, a compact disc-read only memory (CD-ROM) drive, a modem, a hard disk storage device, and a printer. Typically, a computer system's main board, which is a printed circuit board known as a motherboard, is used to electrically connect these components together.
The hard disk storage device can also be referred to as a hard disk drive containing a hard disk, wherein the hard disk is the actual storage medium. A platter is another tern for a hard disk. The hard disk drive is an auxiliary memory unit of the computer system. The hard disk drive contains components enabling data to be received from the associated computer system and then written to the hard disk, and also enabling data to be read from the hard disk and then transmitted to the associated computer system. The hard disk drive includes a magnetic read/write head which flies above the surface of the hard disk while the hard disk is rotating.
The hard disk has a plurality of concentric tracks fi)r storing data. Each track has a plurality of sectors. Some hard disk drives contain several hard disks, each hard disk being horizontally mounted on one shared vertical spindle-axis, so that the hard disks from a stack of hard disks. When a disk drive has a plurality of hard disks, with each disk having its own read/write head, every read/write head is aligned on a separate track of its associated hard disk. A head actuator locks all the heads together so that all heads are at the same position from the center of the disk along a given radius. The vertical stack of tracks formed by such an arrangement is referred to as a cylinder. The number of cylinders in a hard disk drive is the same as the number of tracks on a hard disk of that hard disk drive.
A primary function of the hard disk drive is to receive data from the associated computer system, write the data onto the hard disk without loss of the data, and then read and transmit the data to the computer system when necessary. Therefore, a manufacturer of the hard disk drive not only makes an effort to maximize data recording capacity, but also looks for various means to prevent data loss when writing and reading the data.
In a hard disk drive which uses a thin film head, the data recording capacity is about 1.6 gigabytes and more extended capacity cannot be allowed. To solve this problem, manufacturers of hard disk drives lower a flying height of the read/write head gradually, together with an increased data recording density. But, in the case where the flying height is lowered, data could bc lost or the hard disk's surface could be damaged due to an unexpected problem involving the head and the disk. For example, if microscopic particles exist on the hard disk's surface or if a distortion occurs in a lubricant layer on the hard disk's surface, the flying height of the read/write head will be raised by the above factors temporarily when writing, sequential data. Thus, data will be lost because the correct data cannot be written onto the hard disk's surface, due to the fact that the strength of the magnetic field arriving at the hard disk's surface is attenuated. Such a phenomenon, occurring when the strength of the magnetic field arriving at the hard disk's surface is attenuated, is called a “drop down phenomenon.” Thus, data may be lost in the conventional hard disk drive due to the aforementioned drop down phenomenon. In other words, the drop down phenomenon is a phenomenon which occurs when data is not properly written onto a surface of a hard disk due to the fact that the magnetic field from the read/write head is too weak. The magnetic field might be too weak because the read/write head is too far from the surface of the hard disk. Thc read/write head might be too far from the surface of the hard disk because a contaminant such as a microscopic particle is located on the surface of the hard disk.
Examples of methods and devices pertaining to magnetic read/write heads of hard disk drives are disclosed in U.S. Pat. No. 5,719,722 for Head Tracking System for a Magnetic Disk Drive, and Having an Actuator for Positioning the Read/Write Head to the Target Track Based on Total Error Signal issued to Shimoda; U.S. Pat. No. 5,541,785 for Magnetic Disk Apparatus With Improved Positioning Control of Magnetic Head issued to Sasamoto et al.; U.S. Pat. No. 5,305,157 for Read Circuit Providing Two Different Reference Levels For Reading The Servo Sectors And Data Sectors of a Rotating Data Storage Disk issued to Wada et al.; U.S. Pat. No. 5,233,486 for Method for Correcting Track Counting Errors During Seeks in a Hard Disk Drive issued to Albert; U.S. Pat. No. 5,262,907 for Hard Disc Drive with Improved Servo System issued to Duffy et al.; U.S. Pat. No. 5,650,882 for Disk Unit Performing Control Using Sector Pulses issued to Tsurumi et al.; and U.S. Pat. No. 4,638,230 for Bang-bang Controlled Velocity Command Generator issued to Lee.
Examples of methods and devices for the detection of defects in hard disk drives are disclosed in U.S. Pat. No. 5,661,615 for Detection of Mechanical Defects in a Disc Drive Using Resonant Frequencies issued to Waugh et al. and U.S. Pat. No. 5,748,590 for Apparatus for Inspecting Disc Recording Medium issued to Iwasaki et al.
Additional examples of methods and devices related to disk drives are disclosed in U.S. Pat. No. 4,477,755 for Method of Suppressing Seek-excited Vibration in a Disk Drive or Similar Servo System issued to Rickert and U.S. Pat. No. 5,583,876 for Disk Array Device and Method of Updating Error Correction Codes by Collectively Writing New Error Correction Code at Sequentially Accessible Locations issued to Kakuta. Examples of document retrieval devices in which a search is performed to locate a designated character string are disclosed in U.S. Pat. No. 5,680,612 for Document Retrieval Apparatus Retrieving Document Data Using Calculated Record Identifier issued to Asada et al.
Although presently there are devices and methods pertaining to the improvement of hard disk drives, I have found that there is a need for an enhanced method which minimizes the drop down phenomenon.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a preliminary search method minimizing a poor quality rate in a test process during a manufacturing process by reducing the drop down phenomenon.
It is another object of the present invention to provide a method for cleaning contaminants from a disk drive storage unit.
To achieve the above objects and other objects, there is provided a method for preliminarily searching cylinders in a hard disk drive. The method includes the steps of setting a target cylinder upon receiving a sequential data write command from the external device; setting search cylinders and setting a count value to have a same value as a number of the search cylinders; sequentially searching among the search cylinders for the target cylinder until the count value becomes zero; and writing data on the target cylinder if the count value is zero. Here, the search cylinders are positioned between the target cylinder and a current cyli
Bushnell , Esq. Robert E.
Samsung Electronics Co,. Ltd.
Sniezek Andrew L.
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