Device and method for reading data from and writing data in storage medium

A disk device writes data in or reads data from a disk. The disk device includes a head. The head includes a reading element that reads data from the disk and a writing element that writes data in the disk. The reading element and the writing element are placed apart from each other. For example, the writing element is arranged nearer to the outer periphery of the disk than the reading element is. The disk device includes two stoppers that restrict the movement of the head. The stoppers are arranged such that, when the head moves over the disk, a specific area on the disk is accessible only to the reading element and not to the writing element. Thus, data can be read from the specific area but cannot be written in the specific area.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The present invention relates to a technology for identifying a servo track writer (STW) device used for servo track writing on a disk.

2) Description of the Related Art

The disks of magnetic disk devices are subjected to servo track writing prior to shipping. “Structure and Practical Applications of Hard Disk Device—Principles and Mechanism of Recording/Reproduction & Interface”, published in CQ, issue no. ISBN4-7879-3622-4, P90-93 by Hiroshi Okamura discloses servo track writing. The servo track writing is a process by which head position information, servo information, etc. (hereinafter, “STW information”) are recorded on the disk and is carried out by a dedicated device (hereinafter “STW device”).

FIG. 6AandFIG. 6Bare schematics for explaining the servo track writing. The STW device records the STW information on a magnetic disk with the aid of the magnetic head, and, with the aid of a magnet, transfers the STW information to other magnetic disks from a master medium already having the STW information recorded thereon.

Thus, by using the STW device for servo track writing, the magnetic disk device accomplishes the task of servo track writing more precisely than would be the case if the magnetic disk device itself were to carry out servo track writing. Consequently, defects in the magnetic disk device can be forestalled.

Further, a bar code is affixed to a post-shipment magnetic disk device to make it possible to identify the STW device that was used for servo track writing on the disk. Thus, in case of any malfunctioning of the magnetic disk device, the bar code can be used to identify the defective STW device.

However, conventional technology does not always assure correct identification of the defective STW device.

The reason for this is that the bar code affixed to the magnetic disk device is easily damaged during handling, causing it come off or become worn. Consequently, the information recorded on the bar code cannot be read properly. Further, since the bar code is merely affixed to the magnetic disk device, any unauthorized person may tamper with the bar code information, leading to security breach.

This problem may be countered by recording on the disk an identification information of the STW device. However, since formatting the magnetic disk device erases the identification information, this method is not an appropriate solution.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a storage medium read/write device that reads data from or writes data to a storage medium includes a read/write unit that performs reading of data from and writing of data to the storage medium with the aid of a head provided with a writing member and a reading member placed apart from each other, the reading member being used for reading data and the writing member being used for writing data; and a restricting unit that restricts a range of movement of the head such that a protected area on the storage medium is accessible to the reading member and not to the writing member.

According to another aspect of the present invention, a method of reading/writing of data from/to a storage medium includes reading/writing data from/to the storage medium with the aid of a head provided with a writing member and a reading member placed apart from each other, the reading member being used for reading data and the writing member being used for writing data; and restricting a range of movement of the head such that a protected area on the storage medium is accessible to the reading member and not to the writing member.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention are explained next with reference to the accompanying drawings.

A disk device according to an embodiment of the present invention is explained in general. It is assumed that disk device is a storage medium read/write device. The disk device includes a head having a reading element and a writing element. The reading element and the writing element are placed apart from each other. When the head of the disk device reads data from or writes data to a disk, the disk device restricts the range of head movement, and, by doing so, provides an area (hereinafter, “protected area”) on the disk accessible only to the reading element and not to the writing element.

By storing important data (such as identification information of STW device, encryption key information, etc.) in the protected area, erasure or tampering of the data can be prevented.

FIG. 1is a schematic of a disk device100according to the present embodiment. The disk device100includes a disk110, a spindle motor120, a head130, an arm140, a step-up motor150, an inner stopper160, and an outer stopper170.

The disk110is a metal disk (or a plastic disk) coated or deposited with a magnetic material, and stores and records data. The spindle motor120spins the disk110.

The head130reads data from and writes data to the disk110. The head130includes a writing element (not shown) that writes data to the disk110and a reading element (not shown) that reads data from the disk110. The reading element and the writing element are placed apart from each other.

FIG. 2andFIG. 3are schematics for explaining the positions of the reading element and the writing element in the head130. In the example ofFIG. 2, a writing element130bis provided at a specific distance from a reading element130atowards the inner periphery of the disk110. In the example ofFIG. 3, the writing element130bis provided at a specific distance from the reading element130atowards the outer periphery of the disk110.

When the reading element130aand the writing element130bof the head130are placed as shown inFIG. 2, the outer stopper170is used to restrict the range of movement of the head130, thereby enabling a protected area110a(seeFIG. 4) of the disk to remain safe.FIG. 4is a schematic for explaining the protected area11a. As shown inFIG. 4, the range of movement of the arm140that moves the head130is restricted by the outer stopper170. As a result, only the reading element130ais able to access the protected area110a. The arm140is driven by the step-up motor150shown inFIG. 1.

On the other hand, when the reading element130aand the writing element130bof the head130are placed as shown inFIG. 3, the range of movement of the head130is restricted by the inner stopper160, thereby enabling a protected area110b(seeFIG. 5) to remain safe.FIG. 5is a schematic for explaining the protected area110b. As shown inFIG. 5, the range of movement of the arm140that moves the head130is restricted by the inner stopper160, thus enabling only the reading element130ato access the protected area110b.

Thus, prior to shipping the disk device100, information such as the identification information of the STW device, the identification information of the master medium used when magnetic transfer of the STW information, information (encryption key, etc.) that determines whether specific data should be written to the disk110(for example, whether to install a software), can be stored in the protected area110aor110b, rendering the data safe from tampering and erasure.

Thus, the head130has the reading element130aand the writing element130bplaced apart from each other, and the inner stopper160and the outer stopper170restrict the range of movement of the head130in such a way that the protected areas110aand110bare accessible only by the reading element130a. Consequently, important data can be stored in the protected areas110aand110b, eliminating the risk of erasure or tampering of the data as well as enabling correct identification of the STW device.

Further, since no special storage medium with complex structure is required and the protected areas can be provided on the disk110used conventionally, the manufacturing cost and manufacturing time remain the same as for the conventional storage medium.

When reading data from or writing data to a disk, a storage medium read/write device that includes a head provided with a reading unit and a writing unit placed apart from each other, restricts the range of movement of the head, and by doing so, provides a protected area on the disk accessible only by the reading unit and not by the writing unit. As a result, data stored in the protected area remains safe from tampering and erasure.

Head position information or identification information that identifies the device that has recorded servo information on the disk, etc. are stored in the protected area. Consequently, in the storage medium read/write device, it is possible to correctly identify the device that has carried out the servo track recording.

Information pertaining read/write access permission is stored in the protected area. Consequently, the storage medium read/write device affords improved security.