KR101339429B1 - Optical disc drive and driving method thereof - Google Patents

Abstract

An optical disk drive and a method of driving the same are provided for a host which is not compatible with the optical disk drive, thereby providing connectivity or compatibility with the host by providing file system and device information allowed by the host. Hosts, such as display devices, have a specific set of instructions for compatibility and data exchange with a limited range of specific external media devices, and optical disk drives and drive methods transmit information that is compatible to the host and are internally accepted by the host. By choosing a command set, you are compatible with the host.

Description

Optical disc drive and driving method thereof

The present invention relates to an optical disc drive having compatibility with an A / V (Audio / Video) host device such as a display device such as a receiver, an electronic picture frame, and the like, and a driving method thereof.

An optical disk drive, which is one of the optical media devices, is a representative information storage and playback device. Representative formats of optical discs are compact discs (CDs) and digital versatile discs (DVDs), and are gradually expanding to BDs (Blu-ray Discs). Most DVD media devices secure compatibility with low-capacity compact discs (CDs). Recently, optical media devices having compatibility with CDs, DVDs, and BDs have been introduced.

Representative information display devices include general purpose devices such as computers, while conventional devices include airwaves, cables, and Internet TV receivers. Such a water receiver is a general-purpose video display device capable of receiving various information in real time. These devices have recently been equipped with a function that allows the connection of peripheral devices to display various contents stored in the peripheral devices.

A / V host devices including such receivers allow a limited range of connectivity and thus lack compatibility with various types of media. In addition, the recent A / V (Audio / Video) device has a USB (Universal Serical Bus) host function, so when a USB storage device (USB memory, MP3 player, external HDD, etc.) is connected, the multimedia stored in the device You can play the content. However, A / V devices generally support only the File Allocation Table (FAT) file system defined by International Standard Organization (ISO) 9293, so they do not support CDFS (Compact Disc File System) or UDF (Universal Disc Format). Data on an optical disc used as a file system cannot be played back.

According to exemplary embodiments, an optical disk drive and a driving method thereof compatible with an external host such as a receiver, an electronic picture frame, etc. having limited connectivity are provided.

An exemplary embodiment provides an optical disk drive and a method of driving an optical disk drive capable of generating a file allocation table, which is a core data structure of a FAT file system having general purpose.

An optical disc drive according to example embodiments is:

An information processor for processing information relating to the optical disc;

And an interface connecting the information processor to an external host supporting a FAT file system.

The interface includes a conversion unit for converting the file system information of the native format of the optical disk into information of the FAT file system allowed by the host,

The conversion unit buffer memory for temporarily storing file information from the optical disk;

And a buffer memory for storing information of the FAT file system.

A method of driving an optical disc drive according to an exemplary embodiment is:

Converting file system information of a native format of the optical disc into information of a FAT file system allowed by an external host;

And transmitting the converted file system information to the external host.

According to another embodiment of the present disclosure, a method of driving an optical medium device may further include providing physical host information to the host when the optical medium device is connected to a host device.

According to another embodiment, the host is a receiver.

According to another embodiment, the unique file system of the optical disc is CDFS (Compact Disc File System) or UDF (Universal Disc Format) as defined by ISO 9660.

According to another embodiment, the interface may use a universal serial bus (USB) protocol.

According to another embodiment, the receiver may be automatically detected by identifying the characteristics of the USB device recognition process between the host and the optical disk drive.

Hereinafter, an optical disk drive and a driving method thereof according to exemplary embodiments will be described with reference to the accompanying drawings.

The optical disc described in the embodiments includes all general media in the form of a disc in which information is physically recorded on an optical disc. These discs include CDs and DVDs (DVD-R, DVD-RW, DVD + R, DVD + RW, DVD-RAM), BD, 3D, holograms (near light) and they have their own file systems. Typical file systems for optical discs may include CDFS, UDF, FAT, and the like. The optical disc is mounted in an optical disc drive having an interface that can be connected to an external host such as a receiver. Although such an optical disc is a separate and independent entity, it may be interpreted as a part of an optical disc drive because its function can be exerted by the optical disc drive.

As shown in FIG. 1, the optical disc drive 10 is interconnected by an inter cable 30 as a slave device (peripheral device) to a host such as the receiver 20.

The exchange of information via the interconnect cable 30 is made by the interface of the two devices, the interface may typically include a USB port, USB version 1.0. There are 1.1, 2.0, and 3.0. That is, a USB cable may be used as the inter cable 30, and thus the optical disk drive 10 and the receiver 20 may exchange information with each other by the USB protocol. Meanwhile, according to another exemplary embodiment, the interface may be configured in a wireless manner without an inter cable. There are various known types of wireless methods, and these include wireless radio access methods such as Bluetooth or wireless LAN (WIFI) or wireless optical access using infrared.

Hosts such as a receiver 20 or an electronic picture frame to which an external slave device can be connected support a limited range of file systems. The FAT is typically applied to various types of memory cards such as Compact Flash (CF), Secure Digital (SD), Multi Media Card (MMC), and Memory Stick, as well as HDDs. There are many other filesystems, but hosts cannot support them all, and generally only some of the most widely used filesystems. The receiver 20 as a host includes a product having a content reproducing system such as multimedia broadcasting, as well as cable broadcasting, internet broadcasting, and over-the-air broadcasting reception. The content for playback is obtained from the slave in contact with the outside. However, for example, a receiver that only supports the FAT file system cannot accept content from the optical media device of the CDFS / UDF file system. Embodiments described below ensure the connectivity of an optical disk drive to a host, for example a receiver, that supports any of a limited range of file systems, such as the FAT file system, The present invention relates to a method and apparatus for converting a file system into an arbitrary file system such as a FAT file system allowed by the receiver and transmitting the file system. For example, the water receiver supporting the FAT file system described below does not limit the technical scope of the present invention as an example of a display device, and various display devices may include, for example, an electronic picture frame.

2 is a block diagram illustrating an overall structure of an optical disk drive 10 according to an embodiment.

The optical disc drive 10 includes an optical pickup 12 that reads or writes information from the optical disc 11. The optical pickup 12 includes an optical system such as an objective lens, a laser diode (LD), a photodetector, and a mechanical system that performs focusing and tracking operations while mechanically supporting the optical system. The optical system includes an encoder / decoder and is connected to the information processing unit 13 connected to the interface 15 for connecting to an external host, and the mechanical system is connected to the servo unit 14. The information processing unit 13, the servo unit 14, and the interface 15 are controlled by the central control unit 16.

According to an embodiment, the interface 15 includes a USB port, and thus exchanges information with the receiver 20 which is a host by the USB protocol. At this time, the receiver 30 plays the content received from the optical disc drive by the built-in content reproducing apparatus. In order to provide the content, the optical disc drive 10 and the receiver 20 should be in a state in which information can be exchanged with each other via the interfaces 15 and 21. In addition, the receiver 20 should recognize the optical disk drive 10 as an acceptable device, and obtain recognizable file system information from the optical disk drive 10. Acceptable device means a host, for example, a device that can be recognized by the receiver 20 and accessible by the receiver 20, and a command set in which the host and a device connected thereto are compatible with each other. And file systems. Inaccessible devices are classified as unknown devices and mutual information exchange is impossible. Thus, when an optical disk drive is connected to a host, information must be transferred by the host's query, which is compatible, for example, most widely compatible if the optical disk drive is incompatible with the host. In other words, a code about information of an instruction set mainly used by a block device such as a hard disc drive (HDD), which is a similar information medium, may be transmitted. This can be done by a converter (or converter) built into the interface. Table 1 below defines the command set information as the subclass code of the USB device.

In the USB specification, an optical disk drive belongs to mass storage with a device class code of 08H in the interface descriptor, and a subclass code of 02h as an MMC-5 (ATAPI) command set. ).

However, since the device of the subclass 02h to which the MMC instruction set is applied, that is, the optical disk drive cannot be recognized as a device not supported by the host, the device recognized by the host as an available device, for example, the most common Subclass code 06h using Small Computer System Interface (SCSI) Block Commands (SBC) is transmitted to the host to allow the host to recognize the optical disk drive as an available device. However, if the device of subclass 02h is supported by the host, 02h is transmitted as it is.

In addition, as is well known, optical disc drives such as CDs and DVDs are defined in peripheral code 05h using the MMC instruction set. If the host does not accept this MMC instruction set, an acceptable instruction set, e.g. It can be converted to 00h corresponding to a device using a common SBC instruction set, for example, a direct-access block device such as a magnetic disk drive.

After the optical disk drive is made available to the host by the above method, when directory entry information is requested from the host, the optical disk drive receives the file system information of the native format of the optical disk. Converts and transfers FAT file system information in a recognizable format. That is, the optical disk drive internally has file system information of CDFS / UDF / FAT format, but converts and transmits it to FAT format file system information for host's request. This conversion is done by a converter or converter built into the interface. On the other hand, the FAT format includes a 16-bit FAT16 and a 32-bit FAT32 format as is well known.

In this way, the host can recognize file information including the address and the like of the content stored in the optical disc, and thus the specific content can be accessed and played back.

3 is a conceptual diagram of a connection through a USB interface between a host such as a receiver and an optical disk drive (ODD).

After the host and the optical disk drive (ODD) have been identified to be interchangeable by USB, the host has a master boot record (MBR) stored in the first logical block, logical block address 0 (LBA0). The optical disk drive (ODD) transmits a boot sector and a BIOS parameter block (BPB) in FAT format to the host. Again, when the host HOST requests a directory entry, the optical disk drive ODD transmits directory entry information in FAT format to the host HOST. The host which has obtained the directory entry information in this way can know the position (address) of the data (content) of the optical disc drive (ODD), and is in a playable state in which data can be read through this address. The MBR, BPB, and directory entry information transmitted from the optical disk drive to the host are in FAT format, but internally, the CDFS / UDF format is converted by the converter.

The table below shows Psedo code of the algorithm for converting CDFS / UDF to FAT and shows MakeFAT, a program function for FAT conversion.

FAT conversion function / sector size = 512 Function MakeFat

PASS IN: Integer of fat_offset
PASSOUT: nothing (void)

CALCULATE cur_tbl_start as 512 * fat_offset
CALL ClearFATT with sector_size

WHILE infinite
CALL ReadFATB with clus_start_index RETURING clus_start
CALL ReadFATB with clus_end_index RETURING clus_end

IF clus_start is equal to end of entry mark THEN
QUIT funciton
ENDIF

IF cur_tbl_start? Clus_start && cur_tbl_start <= clus_end THEN
SET buf_idx to 0
SET clus_idx_s to cur_tbl_start
ELSEIF cur_tbl_start <= clus_start && (cur_tbl_start + 512)> clus_start THEN
CALCULATE buf_idx as (clus_start-cur_tbl_start) * 4
SET clus_idx_s to clus_start
ELSE
SET buf_idx to -1
END IF

IF buf_idx is equal to -1 THEN
QUIT funtion
END IF

REPEAT
INCREMENT clus_idx_s

IF clus_idx_s> clus_end THEN
SET clus_idx_s to FAT32_LAST CLUSTER_MARK
ENDIF

CALL WriteFATT with buf_idx and clus_idx_s
INCREMENT buf_idx
UNTIL cur_tbl_start + 512> clus_idx_s
END WHILE
END FUNCTION

In the above pseudocode, clus_start_index and clust_end_index represent the start index and end index of the cluster, which is operated when the host requests a file allocation table (FAT), and stores the FAT offset as an argument or parameter And generates FAT by organizing the FAT entry corresponding to fat_offset into the FATT buffer using the file information stored in the FATB buffer.

4 is a conceptual block diagram of a file system converter according to an embodiment of the present invention having the aforementioned elements. The FATB buffer has a type of ring buffer and is part of the file system converter. The file system translator is part of the interface 15, which allocates and uses a certain area of its own internal memory (RAM). The FATB buffer (first buffer memory) stores a start position, an end position, and a file type of a file stored in the disc when the optical disc is loaded. The FATB buffer (first buffer memory) is used as raw data when converting FAT according to the pseudo code above. To be able. The FATT buffer (second buffer memory) is also a buffer that allocates a certain area of the memory, and organizes FAT entries using file information from the FATB buffer through a function of the algorithm, and stores the organized FAT entries. The FAT generator generates a file allocation table from the offset requested from the host using the file information of the FATB buffer and stores the FATT. Data stored in the FATT buffer is sent to the host through a data transmitter embedded in the interface. According to this structure, the FAT generation and transmission portions operate in parallel in separate blocks, thereby increasing the efficiency in FAT generation and transmission.

5 shows a logical structure of a FATB buffer that stores information about N files (N: natural numbers). When the optical disk drive in which the optical disk has already been loaded is started or a new optical disk is loaded into the optical disk drive, the file change system converter searches the entire file of the optical disk and stores the start position (4 bytes) of the files in the FATB buffer, End position (4 bytes), and file type (1 byte). For reference, UDF and ISO-9660 file systems consistently store file data in a single contiguous area, so that if you know only the beginning and end of a file, you can read the file data.

6 shows the logical structure of a FAT created by a FAT. Fig. 6 shows an example assuming a FAT32 file system in which a sector is 2048 bytes in size and one FAT entry is 4 bytes in size. In the FAT file system, as shown in Fig. 7, file data is stored in the form of discontinuous cluster chains. Therefore, in order to identify the location of the file data, FAT information as shown in FIG. 6 is required. That is, if the file data is stored in the 515, 516, and 600 clusters sequentially starting from 513, the 513 entry of the FAT is assigned the next cluster number 515, 516 is assigned to the 515 entry, and End Of Cluster (EOC) Provides information to record and read file data.

8 is a flowchart of a process of generating a FAT according to the algorithm described above. As described above, the value of fat_offset is received through the parameter, and the sector size is multiplied by 512 and inserted into the instance variable cur_tbl_start (81). In the general case, the FAT is continuously stored in a predetermined size from the LBA32 of the disk, and when a host request is made, the data of the address of the file is read and transmitted. In this case, the appropriate FAT for the requested address must be created and sent to the host. The offset is set based on the start position of FAT. When FAT starts from LBA 32, when the host requests data of LBA 32, fat_offset becomes 0. When requesting data of LBA 33, fat_offset is 1, . Cur_tbl_start (cluster start address) is calculated by multiplying fat_offste by 512 because the current cluster size is 2048 bytes and the address representing the cluster number is 4 bytes. That is, cur_tbl_start indicates the first cluster number among the FAT entries of the requested address.

Then, clus_start and clus_end are set by reading data corresponding to the start and end positions of the file from the FATB buffer (82). As described above, the FATB buffer stores the start position and the end position of the file for all the files on the disk. When the loop is repeated, the start position and the end position of the next file are read and clus_start and clus_end . When the loop is repeated (83) and the value of clus_start is 0x0FFFFFFF (84), it determines that there is no more file information and terminates the algorithm for creating a file allocation table.

In an embodiment of the present invention, creating a file allocation table means writing a FAT entry in a FATT buffer, e.g., having a size of 2048 bytes. As described above, since the size of one FAT entry (cluster number) is 4 bytes, a 2048-byte FATT can represent 512 FAT entries. Compare the start (clus_start) and end positions (clus-end) of the file previously read from the FATB buffer to transfer the FAT requested by the host to cur_tbl_start, and proceed to step "85" if it is greater than clus_start and less than or equal to clus_end. Otherwise, execution proceeds to step "89".

In step 85, the instance variable buf_idx, which stores the buffer index for determining the write position in the FATT buffer larger than the beginning of the file, is set (cleared) to '0', and the temporary variable instance variable clus_idx_s is written to the corresponding buf_idx. The cluster number to be stored is stored (85). Then add 1 to clus_idx_s until clus_idx_s is larger than clus_end (86), and if clus_idx_s is larger than clus_end (87), add 0x0FFFFFFF to clus_idx_s, the end of the cluster chain (88). Next, clus_idx_ is written to buf_idx of the FATT buffer, and the value of buf_idx is increased to '1' (8B). The process of setting clus_idx_s and writing to the buf_idx position of the FATT buffer is repeated until buf_idx becomes larger than 512. That is, if buf_idx after step "8B" is smaller than 512, the process returns to the above-described step "82", otherwise, the process proceeds to step "86".

On the other hand, since cur_tbl_start is the starting cluster number of fat corresponding to the requested fat_offset in step "89", if clus_start is equal to or larger than cur_tbl_start and is smaller than cur_tbl_start + sector size (512), the cl_tbl_start is stored in the FAT in the requested fat_offset. This is an included situation, and the process proceeds to step "8A". In step "8A", (clus_start-cur_tbl_start) * 4 is assigned to buf_idx to determine the first position to be written to the FATT buffer, and clus_start is substituted for clus_idx_s to write to buf_idx. After the initial value has been determined, the process proceeds to step "86".

The above description relates to a typical FAT file system recognition and operation process, and the conversion from the CDFS / UDF format to the FAT format is performed in real time at the conversion unit at the request of the host.

9A and 9B are front and back views of optical disk drives 10a and 10b according to embodiments. The optical disc drives shown in Figs. 9A and 9B are supported by the CDFS / UDF, which is the native file system format of the optical disc drive, when connecting to a host, for example, a receiver, which is not compatible by the native file system as described above. The arrangement of the host selection switches 105 and 105 'for distinguishing and selecting when connecting to a personal computer (PC) is shown. The host selection switches 105 and 105 'may be connected to internal circuits of the optical disk drive 100 to select device information conversion and file system conversion / transmission by the method described above.

9A and 9B, reference numeral 101 denotes a main body, 102 an optical disc tray, 103 a train opening / closing button, 104 an operation status indicator light, 106 an power supply terminal, 107 an interface terminal, for example, a USB terminal. Indicates. The optical disk drive 100 shown in FIG. 9A has a host select switch 105 installed at the front, and the optical disk drive 100 shown in FIG. 9B has a host select switch 105 'installed at the rear. .

Fig. 10 shows an exemplary method of playing (accessing) contents of an optical disc to which file systems of three types (FAT, CDFS, UDF) are applied using a receiver (TV) supporting a file system of FAT format as a host. It is a flow chart.

When the optical disk drive is turned on in the state in which the optical disk device is connected to the host (51), the optical disk drive internally checks the state of the host selection switches 105 and 105 '(52). If the state of the switches 105, 105 'is determined to be not the TV mode (53), it is determined that it is a general universal PC mode, and enters the existing mode, that is, the PC mode 54. If it is determined that the TV mode, and enters the TV mode (55).

Determination of whether the TV mode is used as described above, if there is an external switch, the optical disk drive that does not have an external switch is a software that utilizes the above features, the process of the TV and PC to recognize the USB device is different (S / W) Use the conventional method.

As a first step of the TV mode, the subclass 02h of the USB interface descriptor is changed to 06h, which is a subclass allowed by the TV (56).

Following the subclass change, change to the device type that has the instruction set that the TV accepts. For example, change 05h (Multi media logical unit) using the MMC instruction set to 00h (Direct-access block device, e.g., magnetic disk) using the SBC instruction set (57).

Then, it is checked whether an optical disk exists in the disk tray (58). If it exists, the process proceeds to the next file system verification step, otherwise terminates. The above-mentioned file system converter searches the entire file of the disk, and then stores the start position, the end position, and the file type of the file in the FATB buffer as described above. Note that the UDF or ISO-9660 file system stores file data in a single area, so that file data can be read if only the start and end positions of the file are known.

As a first file system check step, it is determined whether the optical disk is a FAT format disk (59). For example, a DVD-RAM can be formatted as a file system in UDF or FAT. When formatted in FAT, the FAT format is terminated because the TV supports it (5F). If it is not FAT format, it is determined whether the optical disk is a CDFS format disk (5A). If the optical disk is a CDFS-formatted disk, the file system of the optical disk drive is changed from CDFS to FAT so that it can respond to host's inquiries (5B). If the optical disc is not a CDFS format disc, it is determined in the next determination step 5C whether the optical disc is a UDF format disc. If the optical disk is a UDF-formatted disk, the UDF file system is changed to the FAT file system so as to meet the request of the host. (5E)

After the above process, the host can take FAT file system information such as directory entries and FATs (File Allocation Table) from the optical disk drive, thereby uploading and playing contents from the optical disk drive.

The apparatus and method of the above-described embodiments may be used in the case where the connection of the optical disc drive is not allowed or does not support the native file system of the optical disc drive. That is, when an optical disk drive is not compatible with a particular host among various hosts, for example, the receiver, the ability to convert to a file system, for example, a FAT system, which is compatible with device information and file system for the host, and Steps are given to the optical disc drive and the optical disc drive method to broaden its application range.

Various exemplary embodiments of the present invention have been described and shown in the accompanying drawings. However, it should be understood that these embodiments are only part of the various embodiments. Since various other modifications could occur to those of ordinary skill in the art.

1 illustrates an example in which an optical disk drive contacts a receiver.

2 shows a schematic configuration of an optical disk drive according to one embodiment.

3 is a conceptual diagram illustrating a connection through a USB interface between a host TV such as a receiver and a slave ODM according to an embodiment.

4 is a conceptual block diagram of a file system converter according to an embodiment.

FIG. 5 is a logical structure diagram of a buffer memory used for a file system converter according to an embodiment and storing file information obtained from an optical disk.

6 illustrates a structure of a FAT table obtained according to an embodiment.

7 illustrates the structure of a cluster chain discontinuous in a typical FAT system.

8 is a flowchart illustrating a FAT generation algorithm according to an embodiment.

9A is a front view of an optical disk device according to one embodiment.

9B is a rear view of an optical disk device according to other embodiments.

FIG. 10 is a flowchart illustrating an exemplary method of playing (accessing) contents of an optical disk to which three types of formats are applied using a receiver (TV) supporting a FAT format file system as a host, according to another embodiment. .

Claims (19)

An information processor for processing information relating to an optical disk having a file system of a native format; And an interface connecting the information processor to an external host supporting the native format file system or the FAT file system. The interface provides a host that supports file system information of a native format of the optical disc, and provides a file system information of the native format, and a host that supports a FAT file system without supporting a file system of a native format of the optical disc. Includes a conversion unit for converting the information of the FAT file system allowed by the host, The interface provides the host with device information acceptable to the host to the host supporting a FAT file system, and the conversion unit comprises: a buffer memory for temporarily storing file information from the optical disk; And a buffer memory for storing information of the FAT file system. The method of claim 1, And the host is a display device. delete The method of claim 1, Said interface accepts a unique set of commands of an optical disk drive into a set of commands accepted by said host. The method of claim 1, And the unique file system of the optical disc is one of CDFS and UDF. The method of claim 1, And the interface uses a universal serial bus (USB) protocol. The method according to any one of claims 4 to 6, The host is any one of a personal computer (PC) and an air wave receiver (TV). And the interface determines whether the host is a PC or a TV in a process of recognizing the USB protocol between the PC and the TV. The method of claim 1, And the interface uses a wireless protocol. If the host connected to the optical disc drive supports the file system of the native format of the optical disc driven by the optical disc drive, causing the host to directly use the file system information of the native format; And When the host does not support the file system of the native format, the file system information of the native format of the optical disk mounted on the optical disk drive is converted into FAT file system information and transmitted to the host to which the optical disk drive is connected. step; And The optical disk drive providing the host with device information acceptable to the host to the host supporting a FAT file system; Driving method of an optical disk drive comprising a. The method of claim 9, Storing entire file information from an optical disc loaded in the optical disc drive in a first buffer memory, The transmitting may include converting the file information into the FAT file system using the file information stored in the first buffer memory. 11. The method according to claim 9 or 10, The transmitting may include storing the FAT file system information in a second buffer memory and transmitting the FAT file system information stored in the second buffer memory to the host. delete 11. The method according to claim 9 or 10, And the host accepts the unique command set of the optical disk drive into a command set. 11. The method according to claim 9 or 10, The unique file system of the optical disc is any one of CDFS and UDF. 11. The method according to claim 9 or 10, And the optical disc drive exchanges information with the host by a USB protocol. delete delete delete delete

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