KR20090075412A - Method of deleting data of recording medium and apparatus of recording and reproducing data - Google Patents

Abstract

A method for deleting data in a recording medium and an apparatus of recording and reproducing data are provided to obtain security solution for discarded data by removing the data stored in a rewritable medium and a writable medium to prevent restoration of the data. A method for deleting data in a recording medium comprises: a step(S10) performing OPC(Optimum Power Calibration) and calculating optimum recording power; a step receiving the deletion command of the data stored in a recording medium; a step(S20) judging whether the recording medium is a rewritable medium or not; and a step(S40) overwriting the recording medium with laser output power which is higher than the optimum recording power in case the recording medium is the rewritable medium.

Description

Method of erasing data on a recording medium and data recording and reproducing apparatus TECHNICAL FIELD

The present invention relates to a data erasing method and a data recording and reproducing apparatus of a recording medium, and to a data deleting method and a data recording and reproducing apparatus capable of irretrievably deleting data stored on a recording medium.

Optical recording media capable of recording large amounts of data have been continuously developed as CD (CD), DVD (DVD) and next-generation DVD (HD-DVD, BD etc.) with increasing recording capacity. Optical recording media have been developed as storage media that can be used more conveniently by increasing recording capacity as well as increasing recording / reproducing speed.

The optical recording medium includes a read only recording medium for reproducing only data, a write once recording medium for recording data only once, and a rewritable recording medium for rewriting multiple times. There is.

The write once recording medium can record data only once in a recording layer made of dye, and it cannot delete recorded data and record new data. On the other hand, the rewritable recording medium can overwrite the data several times in a recording layer made of a phase change material, so that the recorded data can be deleted and new data can be recorded.

However, in the case of a write-once recording medium, since the overwriting is prohibited, there is no erasing method such as a rewritable recording medium. In addition, even in the case of a rewritable recording medium, even if the recorded data is deleted, there is a possibility of recovering the deleted data by restoring the lead-in area and the file system area of the recording medium.

Therefore, in the case where it is desired to delete data in order to prevent the leakage of important data recorded on the recording medium, the data recorded on the once-writable recording medium cannot be deleted, and the data recorded on the rewritable recording medium is deleted. Even if you do, the possibility of restoring remains.

Accordingly, an object of the present invention is to solve the above problems, and an object of the present invention is to delete a data which can be deleted so that data stored on a recordable recording medium such as a writeable and rewritable recording medium cannot be restored. A data recording and reproducing apparatus is provided.

In order to achieve the above object, a method of erasing data of a recording medium according to the present invention comprises: obtaining an optimal recording power by performing an OPC (optimum power calibration), receiving a command to delete data stored in the recording medium, and Determining whether the recording medium is a rewritable recording medium, and if the recording medium is a rewritable recording medium, overwriting the recording medium with an output power of a laser higher than an optimal recording power.

The recording medium may include a recording layer made of a phase change material, and cause the recording layer to be destroyed in the step of overwriting.

The recording medium includes a lead-in area, a user data area including a file system area in which file system data is recorded, and a lead-out area, and overwriting can be performed for at least the lead-in area and the file system area.

If the recording medium is not a rewritable recording medium, the method may further include determining whether the recording medium is a writeable recording medium once.

When the recording medium is a write-once recording medium, the method may further include overwriting the recording medium with an output power of a laser lower than the optimal recording power.

On the other hand, the data recording and reproducing apparatus according to the present invention sets a pickup unit for overwriting a recording medium and an optimum recording power, receives an instruction to delete data stored on the recording medium, and records the recording medium to be rewritable. And a control unit which determines whether the medium is a medium, and controls the pickup unit to perform overwriting by setting the output power of the laser higher than the optimal recording power when the recording medium is a rewritable recording medium.

On the other hand, the data recording and reproducing system according to the present invention includes a data recording and reproducing apparatus for reproducing or recording data on a recording medium, and a main controller for controlling the recording and reproducing apparatus by transmitting a recording and reproducing command to the recording and reproducing apparatus.

The data recording / reproducing apparatus includes a pickup unit for overwriting the recording medium, setting an optimum recording power, receiving an instruction to delete data stored on the recording medium, and determining whether the recording medium is a rewritable recording medium. And determining, and if the recording medium is a rewritable recording medium, controlling the pick-up unit to perform overwriting with an output power of a laser higher than the optimal recording power.

The main control unit may be a main controller of a computer, a server, an audio device, or a video device.

As described above, the data erasing method and data recording / reproducing apparatus of a recording medium according to the present invention provide a security solution for discarded data by deleting data stored on a rewritable recording medium and a once-writable recording medium in a non-recoverable manner. can do.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

The terminology used in the present invention was selected as a general term that is widely used at present, but in some cases, the term is arbitrarily selected by the applicant, and in this case, the meaning of the term is described in detail in the description of the present invention. The present invention should be understood as meanings other than terms.

1 is a schematic diagram of a recording / playback system according to an embodiment of the present invention. As shown in the drawing, the recording and reproducing system largely includes a data recording and reproducing apparatus 100 and a main control unit 200 for controlling the recording and reproducing apparatus.

The recording and reproducing apparatus 100 includes a pickup section 10, a signal processing section 12, a microcomputer 14, a servo 16, a memory 18, and a control section 20.

The pickup unit 10 includes a laser diode (LD) therein to record data on the surface of the recording medium 300 or to read a signal reflected from the surface of the recording medium 300.

The signal processing unit 12 receives a signal read out from the pickup unit 10 when reproducing the data and restores it to a desired signal value. When the data is recorded, the signal processing unit 12 outputs the data to be recorded to the recording medium 300 as a signal. It modulates and transfers it to the pickup unit 10.

The microcomputer 14 generates a control signal for controlling the tracking and focusing operations of the pickup unit 10 from the signal input through the signal processor 12.

The servo 16 controls tracking and focusing operations of the pickup unit 10 based on the control signal generated from the microcomputer 14.

The memory 18 temporarily stores management information and the like in the recording medium 300 or performs a buffer function for temporarily storing data to be recorded and reproduced.

The controller 20 receives a user's recording or reproducing command from the main controller 200 to record or reproduce data.

On the other hand, when a user issues a data deletion command, the controller 20 receives a data deletion command from the main controller 200 to determine the type of the recording medium 300, and accordingly the signal processor 12 and the pickup unit. The control unit 10 controls the erased data by overwriting the recording medium 300.

In this case, when the recording medium 300 is a rewritable recording medium, the control unit 20 controls the signal processing unit 12 and the pickup unit 10 to set the output power of the laser to be higher than the optimum write power. do. As a result, the recording layer formed of the phase change material of the rewritable recording medium is destroyed. The method of setting the optimum recording power will be described later.

In addition, when the recording medium 300 is a write-once recording medium, the overwriting is performed with the output power of the laser lower than the optimum output power.

The main controller 200 transmits a recording / playback command to the control unit 20 of the recording / playback apparatus 100 and controls the entire system. The main controller 200 may be a main controller of a computer, a server, an audio device, or a video device. That is, the recording / playback apparatus 100 may be an optical drive provided to a personal computer (PC) or the like, or may be a player not mounted on the personal computer.

Therefore, the recording and reproducing apparatus 100 according to the embodiment of the present invention can be applied to both an optical drive and a player used as a single product mounted and operated inside a PC.

When data is recorded on the recording medium 300, the laser beam output from the pickup unit 10 is irradiated onto the surface of the recording medium 300. In this case, when the recording medium 300 is a rewritable recording medium 300 and the recording layer is made of a phase change material, the recording layer is changed to an amorphous state when the laser beam is irradiated on the surface of the recording medium 300. To form a pit.

The laser beam output from the pickup unit 10 may be generated in various kinds. However, in order to record data on the surface of the recording medium 300 or to delete the recorded data, power in the form of a multi-pulse may be provided. At this time, the level of the multipulse is the highest level, the write power capable of recording data by deforming the surface of the recording medium 300, and erasing the surface of the recording medium 300 as an intermediate level. And a read power that can reproduce data without deforming the surface of the recording medium 300 as erasable power and low level.

Therefore, the signal processor 12 forms a multi-pulse to scan each level for an optimal time in consideration of the pit size to be formed on the surface of the recording medium 300, and the pick-up unit 10 receives the input multi-pulse. The laser beam is scanned on the surface of the recording medium 300 by driving the light source inside the pickup.

Pits of different sizes are formed by the laser beam, and a land is formed between the pit and the pit without deformation of the surface of the recording medium 300. Therefore, data is recorded by the combination of pits and lands formed in the recording medium 300.

2 is a flowchart illustrating a data deletion method according to an embodiment of the present invention. Hereinafter, a method of deleting data according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 2.

First, an optimal power calibration (OPC) is performed to correct the laser recording power due to a difference in recording sensitivity of the recording medium film, a difference in recording sensitivity due to temperature, and laser wavelength variation (S10). Set the recording power.

OPC is performed by recording while varying the laser power in the power calibration area (PCA) of the recording medium. OPC may be performed in units of blocks, and OPC is performed in advance for a block of PCA in which OPC is not performed.

3 shows a graph for setting the optimum recording power. As shown in Fig. 3, the optimum recording power is the power value when the jitter is minimum and the asymmetry approaches zero so that the recorded data has the optimal reproduction quality.

In this case, jitter is a measure of an error of the RF signal read out from the recording medium, and refers to a numerical value of how far apart from the integer multiple of the pit length of the groove of the optical disc. In addition, when the optimal recording power is located in the linear region of the signal characteristic curve, asymmetry means a signal characteristic value based on a target which is a value having a predetermined optimal recording power.

Next, when the user inputs a data delete command of the recording medium, the user receives a command to delete data stored on the recording medium.

Next, it is determined whether the recording medium is a rewritable recording medium (S20). At this time, whether the recording medium is a rewritable recording medium may be determined by reading disc information stored in the recording medium.

As a result of the determination, when the recording medium is a rewritable recording medium, the output power of the laser is set higher than the optimum recording power (S30). At this time, the output power of the laser can be increased to the extent that the recording layer of the recording medium made of the phase change material can be destroyed.

Next, data is deleted by overwriting the recording medium with the output power of the laser set above (S40). At this time, the recording layer may be destroyed by rotating the recording medium at a low speed, or overwriting the same area of the recording medium several times.

4 is a schematic diagram showing the irradiation of a laser beam to a recording medium. As shown, the recording medium includes a substrate, a recording layer formed on the substrate, and a cover layer covering the recording layer.

The recording layer is formed between a lead-in area formed on the inner circumferential side of the recording medium, a lead-out area formed on the outer circumferential side, and between the lead-in area and the lead-out area. Data area is included. In this case, as described above, the laser output power is increased to overwrite the recording layer (S40).

In particular, the file system area in which the lead-in area of the recording layer and the file system data of the data area are recorded is overwritten so that playback or recording is no longer possible. In FIG. 4, for example, the file system area is located at the innermost side of the data area. However, the present invention is not limited thereto, and the file system area may be formed at another location of the data area.

At this time, it is preferable to overwrite the entire recording layer, that is, the lead-in area, the data area, and the lead-out area in order to delete data more reliably. However, in order to delete data within a shorter time, only the file system area of the lead-in area and data area may be deleted.

Meanwhile, as a result of the determination (S20), if the recording medium is not a rewritable recording medium, it is determined whether the recording medium is a writeable recording medium once (S50).

When the recording medium is a write-once recording medium, unlike the case of the rewritable recording medium described above, the output power of the laser is set lower than the optimal recording power (S60) so that new data is recorded in the area where the data is recorded. To overwrite (S40). In the case of a write-once recording medium, the recorded data cannot be read simply by performing the overwriting in this way.

In this manner, even in the case of a recordable recording medium, the recording layer is destroyed by erasing the recorded data.

In the case where the recording / playback apparatus is an optical disc drive provided in the host PC, the recording layer of the write-once recording medium or the rewritable recording medium loaded in the optical disc drive by the data erasing command from the host PC, in particular, the lead-in area and the file system area. The recorded data is deleted by overwriting the area where the back data is recorded.

In addition, when the recording / reproducing apparatus is an optical disc recorder, the user deletes data by inputting a delete command through a button provided outside the optical disc recorder.

As described above, according to the data erasing method according to the embodiment of the present invention, by overwriting the rewritable recording medium and the once-writable recording medium, important data recorded on the recording medium may be completely discarded so that it is impossible to restore them. Can be.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings, and the present invention is also provided. Naturally, it belongs to the range of.

1 is a schematic diagram showing a data recording and reproducing apparatus according to an embodiment of the present invention.

2 is a flowchart illustrating a data deletion method according to an embodiment of the present invention.

3 is a graph for explaining the optimum recording power setting in the embodiment of the present invention.

4 is a schematic diagram illustrating an overwriting method for data deletion.

Claims (11)

Performing optimal power calibration (OPC) to obtain optimal recording power, Receiving a delete command of data stored on the recording medium; Determining whether the recording medium is a rewritable recording medium, and If the recording medium is a rewritable recording medium, overwriting the recording medium with an output power of a laser higher than the optimal recording power. Data deletion method of a recording medium comprising a. According to claim 1, The recording medium includes a recording layer made of a phase change material, And a data erasing method of recording medium such that the recording layer is destroyed in the overwriting. The method of claim 2, The recording medium includes a lead-in area, a user data area including a file system area in which file system data is recorded, and a lead-out area; And overwriting at least the lead-in area and the file system area. According to claim 1, If the recording medium is not a rewritable recording medium, determining whether the recording medium is a once-writable recording medium. The method of claim 4, wherein And overwriting the recording medium with an output power of a laser lower than the optimum recording power when the recording medium is a write-once recording medium. A pickup unit which overwrites the recording medium, and Setting an optimum recording power, receiving an instruction to delete data stored on the recording medium, determining whether the recording medium is a rewritable recording medium, and if the recording medium is a rewritable recording medium, A control unit which controls the pickup unit to set a value higher than the optimal recording power to perform an overwrite; Data recording and reproducing apparatus comprising a. The method of claim 6, The recording medium includes a recording layer made of a phase change material, And the pickup section performs overwriting so that the recording layer is destroyed. The method of claim 7, wherein The recording medium includes a lead-in area, a user data area including a file system area in which file system data is recorded, and a lead-out area; And the pickup section overwrites at least the lead-in area and the file system area. The method of claim 6, The control unit determines whether the recording medium is a write once recording medium when the recording medium is not a rewritable recording medium, and when the recording medium is a write once recording medium, And a data recording and reproducing apparatus for controlling the pickup section to overwrite the recording medium with a low laser recording power. A data recording and reproducing apparatus for reproducing or recording data on a recording medium, and A main control unit for controlling the recording and playback apparatus by transmitting a recording and playback command to the recording and playback apparatus. Including, The data recording and reproducing apparatus, A pickup unit which overwrites the recording medium; Setting an optimum recording power, receiving an instruction to delete data stored on the recording medium, determining whether the recording medium is a rewritable recording medium, and if the recording medium is a rewritable recording medium, Control unit for controlling the pick-up unit to perform the overwriting at a high laser output power Data recording and reproducing system comprising a. The method of claim 10, And the main controller is a main controller of a computer, a server, an audio device, or a video device.

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