WO2002061568A1

WO2002061568A1 - Information storage unit

Info

Publication number: WO2002061568A1
Application number: PCT/JP2002/000614
Authority: WO
Inventors: Masahiko Tomikawa
Original assignee: Sanyo Electric Co., Ltd.
Priority date: 2001-01-29
Filing date: 2002-01-28
Publication date: 2002-08-08
Also published as: JPWO2002061568A1

Abstract

An information storage unit for use in digital camera in which a request from a personal computer can be dealt with appropriately when the information storage unit is connected with a personal computer. In an information storage unit employing an magnetooptic disc, data of predetermined format is returned as read data if the magnetooptic disc is in an unused state for an external data read request. The information storage unit comprises means for making a decision whether the area of the magnetooptic disc corresponding to the read request is not yet used or not, and means for forming data of a specified format if that area is not yet used and outputting it as read data.

Description

Technical field

The present invention relates to an information storage device, and more particularly to an information storage device used for a digital camera for storing image information such as a still image. Conventional technology

As a recording device of a digital camera that mainly records a still image, a semiconductor memory, a hard disk, a magneto-optical disk, and the like are used. Semiconductor memories have the disadvantage that they have a relatively small recording capacity, and with the shift in functions from digital still images to moving image recording in digital cameras, small and large-capacity recording devices are desired. Therefore, it is planned to use a recording medium such as a hard disk, a magneto-optical disk, and a DVD disk as a recording device of a digital camera, and research and development are being conducted. Such a recording medium requires processing different from conventional semiconductor memory. For example, when a hard disk is used, there is a problem of initialization of the hard disk. Japanese Patent Application Laid-Open No. Hei 8-767693 provides two format operations, a simple format that does not detect a bad sector and a standard format that detects a bad sector, and consequently hasten the start of a recording operation. There are disclosures about digital cameras that can.

In the case of a storage device using a recording medium such as a magneto-optical disk, when an image of a digital camera is recorded, and when the image is used by a computer or the like, a semiconductor memory card is used. It is difficult to transfer data by removing the memory card from the digital camera, and the main usage is to connect the digital camera to a personal computer with a predetermined interface to perform data transfer. . Summary of the Invention

As described above, when used in connection with a personal computer, a request to read or write data from the personal computer to the information storage device using a magneto-optical disk must be issued. become. At this time, the information storage device

One one one Even if the magneto-optical disk mounted on the device is unused, the device must be configured so that a read error does not occur when a read request is issued from a personal computer.

According to the present invention, in an information storage device using a magneto-optical disk, in response to an external data read request, if the magneto-optical disk is in an unused state, data of a predetermined format is read. It will be returned as a night. Therefore, means for determining whether or not the area of the magneto-optical disk corresponding to the read request is unused, and forming data in a predetermined format when unused, and outputting the data as read data It is provided with means for performing.

According to another feature of the present invention, the means for determining whether or not the data is unused is a means for detecting whether or not the data obtained by the reading process has a predetermined format. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart illustrating an initialization process according to the embodiment.

FIG. 3 is a flowchart showing a reading process according to the embodiment. FIG. 4 is a flowchart illustrating a write process according to the embodiment.

FIG. 5 is a plan view showing a magneto-optical disk.

FIG. 6 is a schematic diagram showing an outline of the ECC block.

FIG. 7 is a schematic diagram showing lower bits of 'ID data.

FIG. 8 is a flowchart showing an algorithm for determining whether each block is unused. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a digital camera using the present invention will be described. Although the illustration and detailed description of the appearance and operation of the digital camera are omitted, the image formed on the CCD by the optical system is digitally processed, subjected to predetermined compression processing such as JPEG, and recorded. It is converted into a suitable format and recorded on a recording medium such as a semiconductor memory card, which is the same as a well-known one. Figure 1 is a block diagram showing the relationship between the main parts of a digital camera and a personal computer. The camera unit 1 is a block that performs predetermined processing on the video signal from the CCD, the CPU 2 is a microcomputer that controls the operation of the camera unit 1 and the magneto-optical drive 3, and the magneto-optical drive 3 is This block records and reproduces predetermined information with respect to the magneto-optical disk 4. Reference numeral 5 denotes an interface section of IEEE 1394, which mediates data transmission and command transmission between the magneto-optical drive 3 and the personal computer 6. Reference numeral 7 denotes a display of the digital camera, which performs various displays for operating the camera. As will be described later, when the recording of a moving image cannot be continued due to a defect in the magneto-optical disk, an indication to that effect is displayed. The display 7 has a menu display for controlling the camera, a playback display of recorded still images and moving images, and a viewfinder function for shooting. · Reference numeral 8 denotes a memory, which is used for CPU work. For example, it is used for the purpose of reading information about a defective area of the magneto-optical disk 4 described later from the magneto-optical disk and temporarily storing the information.

In brief, the photographing operation of the digital camera is as follows. The image information accumulated by the shutter operation is signal-processed in the camera unit 1 and recorded in the magneto-optical drive 3 based on the control of the CPU 2. The image information recorded on the magneto-optical disk 4 is read out under the control of the CPU 2, displayed on the display 、, or transmitted to the personal computer 6 via the interface 5.

The recording and reproducing operations for the magneto-optical disk 4 are well known and will not be described in detail, but the recording and reproducing are performed by using the magneto-optical (thermal) magnetic effect. FIG. 5 is a front view showing the magneto-optical disk 4. The area 51 inside the figure is a disk defect management area, and the area 52 outside the disk defect management area is a disk drive actually used by the user. Is recorded. The magneto-optical disk 4 is logically divided into unit areas called sectors in order to use it efficiently, and it is possible to perform recording or reproduction by designating a desired sector by a predetermined addressing method. it can. In addition, since individual sectors may be defective during the manufacturing process, recording and reproduction may not be possible. Such sectors need to be identified and managed so that they will not be used for future recording and playback. It is. For this purpose, the Disk Defect Management Area (DMA) is used.

That is, for a sector determined to be bad, its address (and in some cases the address of the replacement area) is recorded in the DMA 51. Therefore, the next time the disc is used, the recording / reproducing process can be performed by checking the DMA 51 without recording / reproducing in the defective area.

By the way, two types of defect management methods are used in consideration of the efficiency of disk use. One method is to detect defective areas by certifying the disk before using the magneto-optical disk for the first time. This is the first defect management method. According to this method, the address of the detected defective area is recorded in the DMA area and is not used thereafter.

The second method is mainly to manage the defective area found after the certification, and writes the data to the magneto-optical disk, reads the written data, and checks the correctness of the data. At this time, when it is determined that the area is a defect area, a method of registering a defect area and an alternative area (second defect management method). In this case, the defect information is temporarily recorded in the memory 8 of the main body, and is written to the DMA area of the disk 4 as needed.

These two methods differ in the method of assigning the alternative area. In the first management method, when a defective sector is detected, the next good sector is used immediately. Therefore, even when performing recording and reproduction including the defective area, irregular movement of the pickup for recording and reproduction is not necessary. On the other hand, in the second management method, since a dedicated spare area is used as an alternative area, it may be necessary to move the pickup. Therefore, when the second management method is used, the apparent rate of recording / reproduction may decrease. In other words, in the case of recording / playback at a high rate, recording / playback of moving images, etc., it is necessary to take measures to prevent the recording / playback operation from becoming abnormal. Specifically, it is necessary to make it impossible to record moving images on a magneto-optical disk that requires a large number of defect area management by the second management method.

As mentioned above, the first management method is a method performed by a certificate operation, so it takes a long time to perform the process. Therefore, information recording such as the present invention is When using a storage device, it is desirable that defect management can be performed only by the second management method. This is the reason why this unit can be used even on discs that have not been certified. In the case of the certification, some data is written to the entire user area of the disk. In this case, even if there is a data read request for the user area, the data is written. Can be read. However, this is not guaranteed for uncertified discs.

The data unit for reading and writing in the magneto-optical drive 3 is in units of error correction blocks. In the embodiment, recording and reproduction in the magneto-optical drive 3 are performed in units of 32 kilobytes, but externally, control can be performed so that writing and reading can be performed in units of 2 kilobytes apparently. In other words, the difference in the processing unit must be absorbed by the processing via the server.

First, the operation according to FIG. 2 will be described. In the digital camera embodying the present invention, when the magneto-optical disk is installed in the magneto-optical drive and the power is turned on (step 20), first, in the magneto-optical drive 3, the pickup laser Adjust the power and initialize other circuits (step 21). Then, the data of the DMA is read first (step 22). Then, the data of the DMA is checked to check whether data is recorded in the DMA (whether the DMA is in an unused state) (step 23). The checking method will be described later. Since the fact that no data is recorded in the DMA means that the disc is an unused disc, write data indicating that there is no defect in order to perform the subsequent processing without delay ( Step 24). When normal data is recorded in the DMA, the process proceeds to the next process (for example, the process in FIG. 3).

FIG. 3 is a flowchart showing processing of the read command. After the initialization process in Fig. 2 is completed, the system enters a command waiting state (step 31). For example, when a command is given from the personal computer 6 through the interface 5, it is checked whether the command is a read command for data read from the disk (step 32). If it is not a read command, processing of another command, for example, a write command (described in FIG. 4) is performed in step 33, and the process returns to the command waiting state. If it is a read command, the data in the designated area (logical address) is read from the disk and temporarily stored in a predetermined buffer (step 34). By checking the contents of the buffer, it is checked whether the specified disk area is an unused area (step 35). The details of how to check for unused areas will be described later. If the discrimination result indicates that the area is an unused area, the flow advances to step 36 to set the read size to zero of a designated size, that is, data of a predetermined format in a read buffer, and then to the next step. If it is not an unused area, the data read out as it is can be used, and the process proceeds to the next step 37. In step 37, the data set in the read buffer is transmitted as a reproduction data to the device that has requested the data read, for example, a personal computer. By this processing, data in a predetermined format is returned to the personal computer 6 even when the disc is an unused disc or when the designated area of the disc is unused. Therefore, it is possible to prevent the personal computer from determining that the information storage device of the present embodiment is out of order. In other words, when the magneto-optical drive 3 is used as a general-purpose storage device for a computer via an interface such as IEEE1394, ATA, or SCSI, there is no possibility that the computer will determine that the drive is malfunctioning. Various OSs can be considered for the convenience of using the magneto-optical drive 3, and since there are various file systems, the actual status of commands for the magneto-optical drive cannot be predicted, but the above measures will solve the problem.

In the description of the flowchart in FIG. 3, it is determined whether or not the specified area is unused.However, it is determined whether or not the entire disk to be used is unused. Judgment can also be made based on whether it is used (unrecorded).

FIG. 4 is a flowchart showing the write operation. As in FIG. 3, the command is initially in a command waiting state, and if it is a command other than a write command, it returns to the command waiting state via step 43. A write command is accompanied by an amount in units of 2 kilobytes to be written (n times 2 kilobytes: n is a positive integer) and the logical address of the write destination, and the command is a write command. In case, first, calligraphy The data of 2 kilobytes to be written is stored in the predetermined buffer 1 on the memory 8 (step 44).

As described above, since the data unit of writing and reading in the magneto-optical drive is 32 kilobytes, which is larger than 2 kilobytes, the data in the buffer 1 cannot be recorded as it is. Therefore, the data of the ECC block including the logical address to be written is first read from the magneto-optical disk 4 and stored in the buffer 2 on the memory 8 (step 45). Then, in step 46, the read data of the ECC work is checked to check whether or not the data is an unused area (step 46). The check method will be described later.

If it is determined that the area is an unused area by checking whether or not the area is an unused area, the process proceeds to step 47, where the contents of the buffer 2 are all set to zero, and the process proceeds to the next step 48. In step 48, the data corresponding to the logical address specified by the write command is overwritten with the write data of the buffer 1, and then the whole ECC block is written to the magneto-optical disk. Then, after completing the write command processing, it will be a verge.

Next, a check method for an unused area will be described. As described above, writing and reading of data in the magneto-optical drive are performed in units of ECC programs, which are units of error correction. The ECC block is further divided into a plurality of blocks, for example, 16 blocks, and each block includes data ID indicating the type of the logical address and the like of the block. This data ID 65 has a size of 4 bytes and is as shown in FIG. For the data ID, a data filter 66 is provided in the block to detect the error. Then, using two of the data ID 65 and the error detection data 66, it can be detected whether or not the data ID of the program is incorrect. There is a well-known method for the details of the error detection and the method of detection, so the description is omitted.

As mentioned above, since the ID data 65 also includes the logical address of the block, it depends on the implementation, but the logical addresses should be in a predetermined order. In the embodiment, the four least significant bits of the ID data are arranged in order from “0000” to “111” as shown in FIG. In addition, ID data 6 5 also includes data representing the attributes of the block.

The algorithm for determining whether each block is unused is shown in FIG. The data ID 65 of the 16 blocks and the corresponding error detection data 66 in the read ECC block are checked for correctness of each data ID. When it is detected that all data IDs are erroneous, it is determined that the area is an unused area (step 82). If some of the ID data are correct, proceed to the next step 83 to determine whether the order of the lower 4 bits of the ID data is correct in the ID data determined to be correct. Is checked, and if all of the ID data determined to be correct are incorrect, it is determined that the area is unused. If there is at least one block in the correct order, proceed to the next step 84 and check the attribute data of the block. And the ID that was determined to be correct

If the attribute data of all the data is not normally the scheduled data, it is determined to be an unused area. In other words, if at least one of the above three conditions is satisfied, the ECC block is determined as an unused area.

According to this method, the unused area can be reliably determined, and there is no possibility that the used area is erroneously determined as the unused area.

The above-described magneto-optical recording / reproducing apparatus is used for a digital camera. Still images and moving images can be considered as recording targets of a digital camera. Generally, since the amount of data of a moving image is larger than that of a still image, the transmission rate of a recording / reproducing apparatus required for recording a moving image having a large screen size becomes extremely large. On the other hand, since it is difficult to manufacture a defect-free magneto-optical disk, a magneto-optical disk used in a magneto-optical recording / reproducing apparatus often includes some defective area. The first defect management method described above is based on the premise that the disk is to be certified, and the certification is time-consuming. Therefore, it is difficult to certify all the magneto-optical disks to be used. It is not practical given the quick shooting. Therefore, in the magneto-optical recording / reproducing apparatus of the present embodiment, the certification of the magneto-optical disk is not required. In other words, a magneto-optical disk that has not been certified can be used.

Therefore, when data is written, it is read once and the read result And the write data are compared. If they do not match, the sector is determined to be a defective area, and defect management is performed by the second method. The DMA area of the magneto-optical disk is also provided with an area for storing the number of defective sectors by the second defect management, so that the number of defective areas can be determined.

As described above, the use of the second defect management method inevitably results in the assignment of an alternative area to the magneto-optical disk in which the recording / reproducing pickup must be moved (seeked). I will. If the number of assignments increases, the apparent transfer rate of the recording operation will decrease when attempting to record a large amount of data continuously (for example, when recording a moving image), and the recording operation There is a risk of stopping. Therefore, in the present embodiment, when the number of defective areas exceeds a predetermined number, processing that requires high-speed operation, for example, recording of a moving image is prohibited. Specifically, the number of defective areas of the magneto-optical disk is recorded in the memory 8 used by the CPU 2, and if this number exceeds a predetermined number, the CPU flag is set. Even if there is a moving image recording request from the user, a predetermined message is displayed on the display 7 so as not to accept the request. This prevents the user from interrupting the recording operation halfway, such as by using another disk. In some cases, when the number of defective areas becomes slightly before the number of defective areas for which a moving image recording request is rejected, a display notifying that the magneto-optical disk has been replaced may be displayed on the display 7.

As described above, according to the present invention, when an external data request such as a personal computer is made, it is determined whether the entire disk or the requested area is unused. When unused, data in a predetermined format is returned, so that an appropriate response can be made to a request from a personal computer.

Claims

The scope of the claims

1. In an information storage device using a disk medium connected to a personal computer or the like, a detection means for detecting whether or not the disk medium is unused is provided, and the detection means determines that the disk medium is unused. An information storage device that returns predetermined data in response to a data read request from the personal computer or the like.

2. The information storage device according to claim 1, wherein the detecting means determines whether or not the data read from the disk medium is in a predetermined format.

3. The information storage device according to claim 1, wherein the detection means detects that the defect management area on the disk is unused.