JPH05257810A - Information recording and reproducing device and information recording method - Google Patents

Abstract

PURPOSE:To speed up data recording operation by using a cache while securing safety. CONSTITUTION:When a file is recorded, a noncontrol information discrimination part 24a discriminates record data which is not control information of the file and a cache control part 24b employs a write-back system for the record data which is not the control information of the file and a write-through system for record data which is the control information of the file, so the data which is not the control information is recorded by the write-back system to increase the speed of the recording operation and the control information is recorded at the tail of the file records by the write-through system to report all errors in the file recording to a host system 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus and an information recording method for speeding up data access by using a disk cache when recording data in file units.

[0002]

2. Description of the Related Art The operation of a conventional information recording / reproducing apparatus using a disk cache will be described below with reference to FIG. For information on how to speed up I / O using the disk cache, see Nikkei Electronics 1985.3.1.
1, p.159-187.

FIG. 5 is a block diagram showing the structure of a conventional information recording / reproducing apparatus. In FIG. 5, the host system 11
Are connected to the disk device 12 via the system bus 13. The host system 11 includes a CPU 14 and a main storage unit 15.
And an input / output control circuit 16. CPU4
Reads and executes the program stored in the main storage unit 15. Programs and data are stored in the main storage unit 15. The input / output control circuit 16 is a circuit for connecting the host system 11 to the system bus 13.

On the other hand, the disk device 12 includes a disk control circuit 17, a disk cache 18 and a disk drive device 19.
It consists of The disk control circuit 17 controls the disk cache 18 and the disk drive device 19. The disk cache 18 is a memory for speeding up input / output processing with the host system 11. An information recording medium (not shown) is housed in the disk drive device 19.

In the information recording / reproducing apparatus having the above structure, the data recording / reproducing operation is performed as follows. (1) Data reproduction operation When the disk control circuit 17 of the disk device 12 receives a data read request from the host system 11, if the data of the next block of this data is not in the disk cache 18, the request is issued. The next block of data is read from the disk drive device 19 into the disk cache 18 (prefetch) once together with the requested data, and the requested data is transferred to the host system 11.

If there is a data read request from the host system 11 in this state, the disk control circuit 17 searches whether or not the corresponding data is stored in the disk cache 18. When the corresponding data is stored in the disk cache 18 (hits), the corresponding data is transferred from the disk cache 18 to the host system 11. If the corresponding data is not stored in the disk cache 18 (missed), this data and the data of the next block are sent from the disk drive 19 to the disk cache 18 again.
And read the corresponding data to the host system 11. The data in the disk cache 18 is replaced with new data in the order of not being accessed (LRU algorithm).

In general, there is a high probability that data that has been accessed once will be accessed again, and that the data of the subsequent block will be accessed. Therefore, the probability of hitting the disk cache 18 is high, and at this time, since the data is directly transferred from the disk cache 18 to the host system 11 without waiting for the reading from the disk drive device 19, the data reproducing operation is speeded up. It

(2) Data recording operation The method of controlling the disk cache 18 in the data recording operation is a write-through method in which data is directly written to the disk drive device 19 each time, and a method in which data is once written in the disk cache 18 and collected. At the time of writing, the write-back method can be roughly divided into two types.

First, in the case of the write-through method, when a data write request is issued from the host system 11, the disk control circuit 17 transfers the recording data to the disk drive device 19 and writes the data on the information recording medium. If the block corresponding to the record data is hit in the disk cache 18, the disk control circuit 17 invalidates the corresponding block of the disk cache 18 in order to match the content of the disk cache 18 with the content of the disk drive device 19. Or write the same data to the disk cache 18. With this method, there is no effect of improving the access time with respect to a data write request. In the write-through method, when a data recording request is received from the host system 11, actual data writing to the information recording medium is performed. In this method, the input / output is completed after the completion of the operation of writing data to the information recording medium in the disk drive device 19.

Next, in the case of the write-back method, when the host system 11 requests writing of data, the disk control circuit 17 transfers the recording data only to the disk cache 18. With this method, the disk cache 18
The input / output is completed when the writing of the data to is completed. After that, when free space is needed in the disk cache 18, when a certain time has passed since the data was stored in the disk cache 18, or because the data became unnecessary, the disk cache 18 When the host system 11 requests that the data in the disk match the contents of the information recording medium, the disk control circuit 17 transfers the data in the disk cache 18 to the disk drive device 19 and writes the data in the information recording medium.

In the write back method, the data in the disk cache 18 is still in the disk drive device 19.
If there is a request to write data to the same block again when it is not transferred to disk cache 18
Data will be overwritten. In a temporary file or the like, data write requests for the same block often concentrate. In such a case, the number of times of actual input / output is reduced, so that the data recording operation is speeded up.

[0012]

Here, for example, when an optical disk which is a replaceable medium is used as the information recording medium, due to dust or dirt adhering to the surface of the information recording medium, the data of the data by the disk drive device 19 is changed. Although an error may occur during the write operation, in the above-mentioned conventional write-back method, the completion of the input / output is reported to the host system 11 at the time when the record data is written in the disk cache 18, so the information is recorded later. Even if an error occurs in the disk drive device 19 while actually recording data on the medium, the host system 11 cannot know this. In this case, the host system 11 does not perform error recovery work, and the data to be recorded is lost. As described above, when the data is recorded by using the write-back method, there is a problem that the recording data is lost if an error occurs during the actual writing of the data to the information recording medium.

On the other hand, in the write-through method, since data is written to the information recording medium when a data recording request is made, the host system 11 must know that an error has occurred and perform recovery work for this error. You can Therefore, no data is lost due to the occurrence of an error, but with this method, the disk control circuit 17
Writes data to the information recording medium every time there is a data write request from the host system 11, there is a problem that it takes time to write data.

The present invention solves the above-mentioned conventional problems. It enables the host system to know the occurrence of an error and perform error recovery work, and speeds up the data recording operation using a disk cache. It is an object of the present invention to provide an information recording / reproducing apparatus and an information recording method capable of performing the same.

[0015]

To solve the above problems, an information recording / reproducing apparatus of the present invention has a disk cache which is a memory for speeding up input / output processing, and records / reproduces data in file units. An information recording / reproducing apparatus that uses the last recorded data at the time of recording a file as the control information of the file, the non-control information identifying section for identifying data that is not the control information of the file, and the non-control information identifying section. A cache control unit that sets the operation mode of the disk cache to the write-back method when the identification is performed by the unit, and sets the operation mode of the disk cache to the write-through method when the identification is not performed. It is a thing.

Further, the non-control information identifying section in the information recording / reproducing apparatus of the present invention, when the area in which the main body of the file is written is a data area, the data other than the control information of the file is identified by writing the recorded data. The configuration is such that the destination is identified in the data area.

Furthermore, the information recording method of the present invention uses a disk cache which is a memory for speeding up input / output processing, records data in file units, and the last recorded data at the time of file recording is the above-mentioned. An information recording method used as control information of a file, the step of identifying data which is not the control information of the file, and the step of setting the operation mode of the disk cache to a write-back method when the identification is performed. And a step of setting the operation mode of the disk cache to a write-through method when the identification is not performed.

Further, in addition to the above method, the information recording method of the present invention is such that when the area where the main body of the file is written is a data area, the identification of the data that is not the control information of the file is such that the writing destination of the recording data is This is to identify by looking inside the data area.

[0019]

With the above configuration, when the non-control information identifying section identifies data that is not file control information and it is identified that the recorded data is not file control information, the cache control section operates in the disk cache operation mode. When the data is cached by the write back method and it is not identified that the recorded data is not the control information of the file, the cache control unit sets the operation mode of the disk cache to the write through method and does not perform the data caching. Therefore, the recording data identified as not being the control information is cached in the disk cache by the write-back method, so the speed of the data recording operation is improved, and the control information is written at the end of the file recording operation by the write-through method. The error that occurred in the disk device up to that point is reported to the host system when the data related to the file is written, and the host system can perform error recovery work based on this report. The data recording operation is speeded up while ensuring safety.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an information recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, a host system 21 is connected to an optical disk device 22 which is an external storage device by a SCSI (Smal
l Computer System Interface) connected via bus 23. In this SCSI bus 23, the command is CDB
It is transferred in the form of (Command Discriptor Block).

The host system 21 comprises a CPU 24, a main memory 25 and a SCSI interface 26. The CPU 24 reads out and executes the program stored in the main storage unit 25. The CPU 24 contains a non-control information identifying section 24a and a cache control section 24b.
The main storage unit 25 also stores programs and data. Further, the SCSI interface 26 is an input / output control circuit for connecting the host system 21 to the SCSI bus 23. The non-control information identifying unit 24a of the CPU 24 looks at the area where the recording data is written and identifies the data that is not the file control information in the recording data. Further, the cache control unit 24b sets the SCSI CDB to switch the caching mode of the recording data in the optical disk device 22 between the write-back method and the write-through method.

The optical disk device 22 comprises an optical disk control circuit 27, a disk cache 28 and an optical disk drive device 29. This optical disk drive 29
An optical disk 29a, which is an information recording medium, is stored in. The optical disk control circuit 27 is a SCSI bus 23.
Interprets the command sent from the host system 21 via the disk, and the disk cache 28 and the optical disk drive 29
To control. The disk cache 28 is a memory for speeding up input / output processing. The optical disk drive device 29 records or reproduces data on the optical disk 29a.

FIG. 2 shows the SCSI C of the data recording command.
It is a content diagram of DB. In FIG. 2, the operation code 2Ah is set in the byte 0 of the CDB of the data recording command. The byte 1 bit 3 of the CDB is called the FUA bit and is used for setting the mode of caching recorded data. If this FUA bit is "1",
The device receiving the CDB completes the input / output after actually writing the data on the information recording medium. That is, in this embodiment, the optical disk control circuit 27 uses the disk cache 28 in the write-through method. Also, the FUA bit is "0".
If so, the optical disk control circuit 27 is a disk cache.
28 is used in the write-back method. In byte 2 to byte 5 of the CDB, a logical block address which is an address of the recording data on the optical disc is set. Further, in bytes 7 to 8 of the CDB, the transfer length which is the capacity of recording data is set. Note that the other fields of the CDB are not particularly related to the present invention, and thus the description thereof will be omitted in this embodiment.

FIG. 3 is an area diagram on the optical disk 29a in this embodiment. In FIG. 3, an area on the optical disk 29a is a system reserved area, FAT (File Allocation Ta
ble) area, directory area, and data area. Each of these areas is arranged at a fixed address of the optical disc 29a, and the plurality of areas do not overlap.
The boot program is written in the system reserved area. This boot program is read only when the system is started, and is not accessed during normal file access. Further, in the FAT area, FAT, which is a table showing the arrangement information of where the main body of the file exists on the optical disc 29a, is stored. Further, the directory area stores a directory indicating the logical position of the file. Further, the data of the file body is stored in the data area. In the present embodiment, the file control information is the FAT and the directory which are the information other than the main body of the file that is accessed when the file is recorded.

FIG. 4 is a flow chart showing the flow of processing in the host system 21 of the information recording / reproducing apparatus of FIG. As shown in FIG. 4, in the information recording method, a data recording operation is started, and first, a SCSI CDB is created in step S1 and each field other than FUA such as an operation code, a logical block address, and a transfer length is set.
Next, in step S2, it is determined whether or not the logical block address of the CDB is included in the data area. If the logical block address is included in the data area, the FUA bit of the CDB is set to "0" in step S3, and if it is not included, C is set in step S4.
Set the FUA bit of DB to "1". After this, SC
The created CDB and the recording data are sent to the SI bus 23 in step S5, and the process ends.

The file recording operation in the above information recording / reproducing apparatus will be described in detail below. In the following description, regarding the data read operation,
Since the procedure is similar to that of the conventional example, its details are omitted here. The file recording operation is performed in the following order.

(1) Reading the directory The host system 21 reads the directory from the optical disk device 22 to the main storage unit 25 and searches the read directory for an entry that matches the file name.

(2) Writing File Name to Directory When the host system 21 already has an entry with the same file name in the directory stored in the main memory 25, it sets the file size of this entry to 0. If the same entry as the file name does not exist in the directory, an entry with a new file name with a file size of 0 is added to the directory.

This data is recorded as follows. The CPU 24 of the host system 21 creates the SCSI CDB, sets the operation code to 2Ah, the address of the directory where the logical block address is written, the length of the directory where the transfer length is written, and other than the FUA. Here, all the fields are set to 0 (step S1). Next, the non-control information identifying unit 24a of the CPU 24 determines whether or not the logical block address of the CDB is included in the data area (step S).
2). Here, since the recording data is a directory and its logical block address is not included in the data area, the cache control unit 24b of the CPU 24 causes the CDB FUA to
The bit is set to "1" (step S4). After this,
The CPU 24 drives the SCSI interface 26, and S
The created CDB and the directory stored in the main memory 25 are sent as recording data to the optical disk device 22 via the CSI bus 23 (step S5). And
In the optical disc control circuit 27 of the optical disc device 22, the C
When the DB is received, since the FUA bit is set to "1", the disk cache 28 is controlled by the write-through method. That is, the data of the same block on the optical disk 29a in the disk cache 28 is invalidated, and at the same time, the recording data is recorded on the optical disk 29a stored in the optical disk drive 29. After waiting for the end of this operation, the optical disk control circuit 27 reports the normal end of the command to the host system 21.

(3) Reading the FAT The host system 21 reads the FAT from the optical disk device 22 into the main memory 25 and searches for an empty area on the optical disk 29a for writing a file.

(4) Writing of data in the file body The host system 21 records the data in the file body.
When recording the file body, a plurality of data may be recorded instead of only one data recording. Particularly for temporary files, data recording is often performed a plurality of times for the same block on the optical disc.

Each data recording is performed as follows. CP
U21 creates the CDB and sets the operation code to 2
In Ah, the address of the data for recording the logical block address, the length of the data for recording the transfer length, and all other fields other than the FUA are set to 0 (step S1). Next, the non-control information identifying unit 24a determines whether or not the logical block address of the CDB is included in the data area (step S2). Here, since the record data is the data of the main body of the file, and its logical block address is included in the data area, the cache control unit 24
b sets the FUA bit of the CDB to "0" (step S3). After that, the CPU 24 sends the created CDB and the recording data stored in the main memory 25 to the optical disk device 22 (step S5).

The optical disc control circuit 27 uses the F of this CDB.
Since the UA bit is set to "0", the disk cache 28 is controlled by the write back method. That is, the optical disk control circuit 27 stores the recorded data in the disk cache.
When it is transferred to 28, the normal end of the command is reported to the host system 21.

Therefore, in writing the data of the file body, the data recording operation is speeded up by performing the caching by the write-back method. (5) Writing FAT The host system 21 creates an FAT indicating the arrangement information of the newly written file body on the optical disc and records it. In order to ensure security, the FAT has exactly the same information written in two places in the FAT area. Therefore, the data recording is performed twice. Since the logical block address of the CDB at the time of FAT recording is not included in the data area, as in the case of the data recording in “(2) Writing the file name to the directory”, the disk cache 28
Is controlled by a write-through method to record each data.

(6) Writing the data of the file body The host system 21 is
Data that is smaller than the block size of the optical disc 29a is recorded. This data is usually the last block of the file.

Since the recorded data is a part of the body of the file and the logical block address of the CDB is included in the data area, "(4) Writing of data in the file body"
Similarly to the case of (3), data recording is performed by controlling the disk cache 28 by the write-back method.

(7) Reading the directory The host system 21 reads the directory from the optical disk device 22 into the main memory 25, and searches again for an entry that matches the file name.

(8) Writing File Size to Directory The host system 21 sets the file size of the entry of the corresponding file in the directory stored in the main storage unit 25 to the capacity of the main body of the file.

Since the logical block address of the CDB at the time of directory recording is not included in the data area, "(2)
Similar to the case of the data recording in “writing the file name to the directory”, the data recording is performed by controlling the disk cache 28 by the write-through method.

In the above file recording operation, even if an error occurs in the optical disk device 22 while the optical disk control circuit 27 is using the disk cache 28 by the write-back method, the host system 21 recovers this error. It is possible. As an example, a case where an error occurs during data recording in “(4) Writing data in file body” will be described.

In "(4) writing data in the file body", since the disk cache 28 is controlled by the write-back method, the optical disk control circuit 27 causes the optical disk device 22 to normally terminate the command to the host system 21. After reporting, the actual data is written to the optical disk 29a.

Since the host system 21 is informed that the command has been normally completed, the host system 21 next performs "(5) write FAT". Here, the FUA bit of the CDB is "
1 "and the disk cache 28 is controlled by the write-through method, so the optical disk control circuit 27 writes all the recording data existing in the disk cache 28 to the optical disk 29.
After the data is actually recorded in a, the data for which the write-through write request is made, that is, the FAT is recorded.

However, it is assumed that an error occurs in the recording data writing in "(4) Data writing of file body" during the actual data writing to the optical disc 29a because dust is attached to the surface of the optical disc 29a. .. This error is reported from the optical disk control circuit 27 to the host system 21 as an error for the previous command, a so-called deferred error.

Upon receipt of this report, the host system 21 requests the user to clean the optical disk 29a, and after the user cleans the optical disk 29a, performs error recovery processing such as repeating the recording operation of the corresponding file. be able to.

That is, in the present invention, attention is paid to the fact that the control information is recorded at the end of the recording operation of each data in the recording of the file, and at least the control information is controlled by the write-through method to control the file. All the data is recorded on the information recording medium by the time the recording of the above is completed to ensure the safety of the data.

As described above, according to the embodiment of the present invention, the non-control information identifying section 24a identifies data that is not file control information because the recording destination of the recording data is within the data area. Then, the cache control unit 24
In b, the operation mode of the disk cache 28 for recording data that is not file control information is a write-back method, and the operation mode of the disk cache 28 for recording data that is file control information is a write-through method. As a result, the data which is not the control information is cached and recorded in the disk cache 28 by the write-back method, so that the speed of the data recording operation is improved, and the control information is finally written by the write-through method in the file recording operation. Written by the host system 21
Can know the error that occurred in the optical disk device 22 in all the data recording operations of the file.

In this embodiment, the data which is not the control information of the file is arranged in the continuous area on the information recording medium, but the areas of the data which are not the control information of the file are arranged dispersedly. Even in this case, the present invention can be applied when this area can be uniquely specified. Further, although the information recording medium is described as an optical disc in the present embodiment, the present invention can be applied to the information recording / reproducing apparatus and the information recording method using the other information recording medium in exactly the same manner.

[0048]

As described above, according to the present invention, when the data is recorded, the record data which is not the control information of the file is identified, and when the record data is not the control information of the file, the caching is performed so that the record data is the file. If the control information is the control information described above, the non-control information data is cached by stopping the caching of the recording data, so that the speed of the data recording operation can be improved, and the data is written last in the file recording operation. When the control information is detected, the caching is stopped and the data recording is performed. Therefore, the host system can know the error that occurred in the disk device in the recording operation of the corresponding file, and therefore the data recording can be performed while ensuring the safety. The operation speed can be increased, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an information recording / reproducing apparatus in an embodiment of the present invention.

FIG. 2 is a content diagram of a SCSI CDB of a data recording command.

FIG. 3 is an area diagram on an optical disc 29a in the present embodiment.

4 is a flowchart showing a flow of processing in a host system of the information recording / reproducing apparatus of FIG.

FIG. 5 is a block diagram showing a configuration of a conventional information recording / reproducing apparatus.

[Explanation of symbols]

 21 Host system 22 Optical disk device 23 SCSI bus 24 CPU 24a Non-control information identification section 24b Cache control section 25 Main memory section 26 SCSI interface 27 Optical disk control circuit 28 Disk cache 29 Optical disk drive 29a Optical disk

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Takagi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. Information having a disk cache as a memory for speeding up input / output processing, recording / reproducing data in file units, and using last recorded data at the time of file recording as control information of the file. In the recording / reproducing apparatus, a non-control information identifying section that identifies data that is not the control information of the file, and a write-back method that determines the operation mode of the disk cache when the non-control information identifying section identifies the data. An information recording / reproducing apparatus further comprising: a cache control unit that sets the operation mode of the disk cache to a write-through method when the identification is not performed. 2. The non-control information identifying section, when the area in which the main body of the file is written is a data area, identifies the data that is not the control information of the file by writing the recording data in the data area. The information recording / reproducing apparatus according to claim 1, wherein the information recording / reproducing apparatus is configured to be identified by seeing. 3. An information record using a disk cache, which is a memory for accelerating input / output processing, to record data in file units and use the last record data at the time of file recording as control information of the file. A method of identifying data that is not the control information of the file, a step of setting the operation mode of the disk cache to a write-back method if the identification is performed, and the identification is not performed. And a step of setting the operation mode of the disk cache to a write-through method. 4. When the area in which the main body of the file is written is a data area, the identification of the data that is not the control information of the file is made by recognizing that the write destination of the recording data is in the data area. The information recording method according to claim 3,