JP2006309403A - Information recording and reproducing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information recording and reproducing system reducing reading/writing time without access to a disk when rereading or rewriting. <P>SOLUTION: A host computer 1 has a function to set predetermined data in a cache buffer 22 of an information recording and reproducing device (disk drive) 2 to be unrewritable. Accordingly, by setting the data which is already known to be reread by the host computer 1 to be unrewritable, it is prevented that required data is deleted from the cache buffer 22, and the access to a disk 25 do not occur at the time of rereading or rewriting. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an information recording / reproducing system having a host computer and an information recording / reproducing apparatus connected to the host computer via an interface, and more particularly to a method for controlling a cache buffer of the information recording / reproducing apparatus.

Conventionally, a disk recording / reproducing apparatus controlled by a host computer is provided with a cache buffer for temporarily storing data read from the disk. If data read from the disk exists in the cache buffer, the disk is accessed. The data can be taken out from the cache buffer without any problem. A technique related to such a cache buffer is described in, for example, Japanese Patent Laid-Open No. 2001-014109 (Patent Document 1).
JP 2001-014109 A

  The conventional cache buffer cannot control the data to be stored from the host computer, but simply replaces the old data with the newly read data, so if there is no data that is known to be read again, it will be read again. There was a problem that it sometimes took time to access the disk.

  An object of the present invention is to provide an information recording / reproducing system capable of shortening read / write time without access to a recording medium at the time of re-reading or writing.

  To achieve the above object, the present invention includes a host computer and an information recording / reproducing device connected to the host computer via an interface, and the host computer instructs the information recording / reproducing device to input / output data. In the system, the information recording / reproducing apparatus has a cache buffer, and the host computer sets predetermined data in the cache buffer to rewrite prohibition.

  In the present invention, the host computer has a function of setting the predetermined data in the cache buffer of the information recording / reproducing apparatus connected via the interface to rewrite prohibition. Therefore, by setting the data that the host computer knows to read again to prohibit rewriting, the necessary data is not erased from the cache buffer, and access to the recording medium does not occur at the time of reading or writing again.

  According to the present invention, by setting the predetermined data in the cache buffer of the information recording / reproducing apparatus connected via the interface to the host computer, the data that is known to be read again can be set to the rewrite prohibition. Therefore, there is no deletion from the cache buffer, there is no access to the recording medium at the time of reading or writing again, and the read / write time can be shortened.

  Next, the best mode for carrying out the invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The system of FIG. 1 records or reproduces AV data such as video and audio by a disk drive 2 through a host computer 1. When AV data 11 is input to the host computer 1 during recording of AV data, the codec 13 performs encoding processing to MPEG or the like through the input / output device 12, and the encoded data is temporarily stored in the memory 14 and then the interface 15 And sent to the disk drive 2.

  The data sent to the disk drive 2 is temporarily stored in the cache buffer 22 through the interface 21 and written to the disk 25 which is an information recording medium such as an optical disk through the disk controller 23. Reference numeral 26 denotes actual recording data written on the disk 25, and writing is performed by the recording / reproducing head 24. The position actually written on the disk 25 is designated by a file system controlled by the CPU 10 on the host computer 1. Further, not only AV data but also management information such as a file system is recorded on the disk 25, and these data are created by the CPU 10 in the host computer 1.

  When AV data is played back, the data 26 recorded on the disk 25 is read by the disk controller 23 through the recording / playback head 24 and stored in the cache buffer 22 and then sent to the host computer 1 through the drive side interface 21. . Data sent to the host computer 1 is stored in the memory 14 via the host-side interface 15, decoded by the codec 13, and then output as video and audio through the input / output device 12.

  Management data other than AV data is not sent to the codec 13 and is processed by the CPU 10 on the memory 14. At this time, the position of data on the disk 25 is designated by the file system on the host computer 1. In the present embodiment, one file may be recorded in a continuous area or a plurality of data recorded in different areas, and a single piece of data recorded in a continuous area that forms a part of the file is stored. This is called an extent.

  FIG. 2 shows a conventional cache buffer. The cache buffer is a memory for temporarily storing data read / written from / on the disk by ECC decoding. For example, the ECC block has 64 KB. This is associated with the sector address of the disk in units of ECC blocks (64 KB), managed by the CPU 20 of the disk drive 2, the newly read data overwrites the old data, and the latest data is always saved. Is done.

  Since the host computer receives a data read / write request in units of sectors (2 KB), the necessary data is transferred to the host computer in units of 2 KB from the data of 64 KB written on the cache buffer, or sent from the host computer. Rewrite it with the data you have received.

  When there is a data read instruction from the host computer, if there is an ECC block (64 KB unit) containing data on the cache buffer, the data is read from the cache buffer without accessing the disk, but if it does not exist in the cache buffer. A new read from the disk.

  In addition, when there is a data write instruction from the host computer, if there is data on the cache buffer, it is sufficient to rewrite only the necessary part and write it back to the disk, but if it does not exist in the cache buffer, It is necessary to read the ECC block including the corresponding data from the disk, rewrite the necessary part, and write it back to the disk.

  FIG. 3 shows the cache buffer memory of this embodiment. The configuration and operation are the same as in the prior art, except that the data written to the cache buffer 22 can be set to be overwritten prohibition in units of ECC blocks (64 KB) in accordance with instructions from the host computer 1 (CPU 10). That is, the cache buffer 22 has an overwrite-inhibited part and an overwritable part, and data newly read from the disk 25 is overwritten from old data in the overwritable part. It remains on the cache buffer 22 until it is.

  In this way, data that is frequently read and rewritten, such as management data, can be left on the cache buffer 22, and the number of accesses to the disk 25 can be reduced.

  4 and 5 are flowcharts showing a data reading procedure from the disk and a data writing procedure to the disk according to this embodiment. FIG. 4 shows a data read procedure. First, when a data read command is issued from the host computer 1 to the disk drive 2, it is checked whether or not there is an ECC block including data designated by the CPU 20 in the cache buffer 22 (S101).

  If the designated data exists in the cache buffer 22, the corresponding part is transferred to the host computer 1 (S103). If it does not exist, an ECC block (64 KB unit) containing data is read from the disk 25 and copied to the overwrite-permitted portion in the cache buffer 22 (S102), and then the corresponding data is transferred to the host computer 1 (S103). .

  Next, it is determined whether or not the read data is designated as overwriting prohibition by the host computer 1 (S104). If overwriting is prohibited, the ECC block including the corresponding data in the cache buffer 22 is determined. Overwriting prohibition is set (S105). On the other hand, if the overwriting prohibition is not set, the ECC block is overwritten over (S106).

  FIG. 5 shows a data writing procedure. First, when a data write command is issued from the host computer 1 to the disk drive 2, it is checked whether or not there is an ECC block including data designated by the CPU 20 in the cache buffer 22 (S201). If there is an ECC block (64 KB unit) containing data to be written in the cache buffer 22, the data in the corresponding part is rewritten (S203) and written to the disk 25 in ECC block units (S204).

  If it does not exist, the ECC block including the corresponding data is read once from the disk 25 to the cache buffer 22 and copied to the overwritable portion of the cache buffer 22 (S202). Thereafter, the corresponding data is rewritten (S203), and the rewritten ECC block is written back to the disk 25 (S204).

  Next, it is determined whether or not the written data is designated to be overwritten by the host computer 1 (S205). If overwriting prohibition is set, the ECC block including the corresponding data in the cache buffer 22 is set overwriting prohibition (S206). If overwriting prohibition is not specified, the ECC block is set overwriting permission (S207). .

  Next, the effectiveness of the present invention will be described with specific examples. FIG. 6 shows the data arrangement on the disk. In order to improve the access speed of the disk 25, management information such as applications and file systems are concentrated in the inner peripheral area of the disk, and normal data such as AV data is not stored. Recorded in the outer area. In this case, when the management information is read collectively when the disc is inserted, or when the management information is updated in the middle, a long distance seek does not occur and the access time is shortened.

  FIG. 7 is a diagram showing an example of data arrangement in the memory 14 on the host computer 1 when the AV data is actually recorded on the disk 25. AV data is arranged in the AV data area 142, and management information such as a file system for managing the AV data is arranged in the normal data area 141. In addition to this, an area used by hardware may exist, but is omitted in the present embodiment.

  The AV data area 142 is used as a ring buffer when recording / reproducing AV data in real time, and also has a function as a shock proof memory. In FIG. 7, the AV data is arranged after the memory address 1024 KB and is divided into 512 KB, which is a write command unit to the disk drive, for convenience. Also, management information as file system information is arranged on the memory with a size of 8 KB from the position of the memory address 512 KB.

  Considering that AV data is actually written to the disk in real time, a process of updating management information such as a file system may be performed at regular intervals as a measure against instantaneous interruption during writing. This is because even if an instantaneous interruption occurs and the data on the memory disappears, the data up to the previous file system update can be reproduced on the disc.

  An example of read and write commands from the disk drive 2 at this time is shown in FIG. The command is a read command (Read) and a write command (Write), and there are four parameters: memory 14 address, data size, disk address, and overwrite prohibition setting. Memory addresses and data sizes are shown in KB units, and disk addresses are shown in sector units (2 KB).

  First, management information (file system information or the like) related to recording AV data is read from the disk 25. As shown in FIG. 7, the management information for 8 KB is read from the sector address 5000 on the disk 25 to the address 512 KB on the memory 14. At this time, a 64 KB ECC block including management information 8 KB is read from the disk into the cache buffer 22, but this management information needs to be read from the disk again at the time of update. Set it.

  This eliminates the need to read from the disk again. Note that if management information for AV data is only newly created and does not exist on the disc at first, the management information read procedure is omitted.

  Next, a procedure for recording the AV data on the disk 25 is performed. During the recording of the AV data on the disk 25, the management information (file system information) is updated. That is, after the AV data 1 is recorded on the 512 KB disc, the updated management information is recorded 8 KB, and then the AV data 2 is recorded 512 KB.

  At this time, the memory address and data size as the recording source are as shown in FIG. 7, and the sector address on the disk 25 as the recording destination is recorded on the outer periphery (100,000,100256) of the disk in the case of AV data. Information is recorded on the inner circumference (5000). Since 256 sectors on the disk correspond to 512 KB, the 100256 sector, which is the recording start position of the AV data 2 on the disk, is the next sector after the recording end position of the AV data 1 on the disk.

  In addition, if the ECC block including the updated portion is not in the cache buffer, the corresponding portion needs to be read from the disk once. In this case, since the ECC block read last time is set to prohibit overwriting and always exists in the cache buffer, it is only necessary to rewrite the updated part and write it back to the disk. Furthermore, although overwrite prohibition is set here as well, overwriting may be permitted if it is not necessary in the future.

  FIG. 9 shows the movement of the recording / reproducing head on the disk at this time. The numbers in the figure indicate the order in which the heads move. First, AV data 1 is recorded (1). Next, since the file system is updated as a measure against instantaneous interruption during recording of AV data, a jump is made to the management information area (2). When the file system information is updated (3), it returns to the end of the AV data being recorded (4), and recording of the AV data 2 is resumed (5).

  At this time, in the update of the file system information, if the ECC block including the updated portion is not on the cache buffer, it is necessary to read the corresponding portion from the disk once. The process of (3) is performed by reading the pre-update data from the disk. Therefore, a complicated procedure of writing the updated data to the disk occurs.

  In this way, when updating management information such as a file system at regular intervals, if the ECC block including the management information is not present in the memory, it is necessary to read the corresponding portion from the disk 25 once. Due to time, real-time recording may fail.

  In this embodiment, by setting the ECC block including the management information to be overwritten in the cache buffer, the rewrite data always exists in the memory, so the procedure of reading from the disk can be omitted, and the disk access is written. Since it is only an operation, the possibility that real-time recording fails will be significantly reduced.

1 is a block diagram illustrating an embodiment of a system according to the present invention. It is a figure which shows the conventional cache buffer. It is a figure which shows the cache buffer of this invention. It is a flowchart which shows the read-out procedure from the disc of this invention. It is a flowchart which shows the write-in procedure to the disc of this invention. It is a figure which shows the data arrangement | positioning on a disk. It is a figure which shows the data arrangement | positioning of the memory on a host computer. It is a figure which shows the example of the command transferred to a disk drive from a host computer. It is a figure which shows the motion of the recording / reproducing head at the time of real-time recording.

Explanation of symbols

1 Host computer 2 Disk drive 10 Host side CPU
11 AV data 12 Input / output device 13 Codec 14 Memory 15 Host side interface 20 Drive side CPU
21 Drive side interface 22 Cache buffer 23 Disk controller 24 Recording / playback head 25 Disk medium 26 Recorded data 141 Normal data area 142 AV data area

Claims (3)

A system comprising: a host computer; and an information recording / reproducing apparatus connected to the host computer via an interface, wherein the host computer instructs the information recording / reproducing apparatus to input / output data. And the host computer sets the predetermined data in the cache buffer to prohibit rewriting. 2. The information recording / reproducing system according to claim 1, wherein the cache buffer is controlled in units of ECC blocks, and the rewrite prohibition setting is set in units of ECC blocks. 2. The information recording / reproducing system according to claim 1, wherein the input / output data is smaller than an ECC block size.

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