JPH0793098A - Unit and method for buffer control - Google Patents

Abstract

PURPOSE:To increase the hit rate of data in a buffer memory used as a cache memory when data are read out as to a buffer control unit and buffer control method regarding a cache memory system which is used to increase the speed of a read from an optical disk. CONSTITUTION:The control unit is equipped with a driving means 2 which reads data out of the optical disk 5 within a specified range and stores the data in a specified area and a buffer memory 4 which consists of plural divided areas and stores the read data. And, the control unit is equipped with an interface means 3 which instructs the driving means 2 to read data by specifying a read range regarding a request to read the data out of the optical disk and one divided area of the buffer memory 4, and stores the read data in one divided area of the buffer memory 4 when a host device makes the request to read data out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer control device and a buffer control method according to a cache memory system used to increase the read speed from an optical disk.

[0002]

2. Description of the Related Art In recent years, in an image filing apparatus using an optical disk for registering and reading image information, for example, when data is read from the optical disk and transmitted to a host computer, the read data is temporarily stored in a buffer memory ( A so-called cache memory system is used in which the data is stored in a static storage medium (such as a semiconductor having a high read speed) and transmitted to the host computer, and the stored data is used in subsequent read requests. According to this method, if the data related to the read request hits (exists) in the buffer memory, it is sufficient to directly read the data, so that the read speed is apparently improved.

Therefore, in the cache memory system, the data stored in the buffer memory is managed. For example, in an image filing apparatus that uses a buffer memory as one area and transmits data via this buffer memory, the data in the read range requested by the host computer has hit the data buffer memory. If not, the data is read from the optical disc. Then, when this data read occurs, the read data is stored in the buffer memory, so that the content of another data in the buffer memory that has been managed until then is rewritten.

[0004]

When the buffer memory as a whole is used as one area and the data is read from the optical disk, the storage of this data leaves the data managed up to that point in the buffer memory. For example, when this data is read frequently, the hit rate in the buffer memory becomes low during subsequent read requests.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a buffer control device and a buffer control method capable of increasing the data hit rate of a buffer memory used as a cache memory when reading data. I am trying.

[0006]

According to one aspect of the present invention, a buffer memory composed of a plurality of divided areas and data registered in an optical disk are read out in a designated range and a predetermined area of the buffer memory is read. The read-out storage means to store in and the data read request from the host device,
A buffer control device having means for reading and storing data by designating a read range related to the read request of the data registered in the optical disc to the read storage means and a specific area of the buffer memory. According to another aspect of the present invention, drive means for reading data registered in the optical disc in a designated range and storing the data in the designated area,
When a data read request from the host device is made up of a plurality of divided areas and stores the read data, the data related to this read request is stored in the buffer memory at the time of the previous read and remains as it is. If so, it is read and transmitted to the host device. On the other hand, if the data related to the read request does not exist in the buffer memory, the read range of the data registered in the optical disc to the drive means and the read range related to the read request and Designate a specific divided area of the buffer memory to instruct data reading,
A buffer control device having an interface means for storing the read data in a specific divided area of the buffer memory is obtained.

According to still another aspect of the present invention, when the data registered on the optical disc is read in a designated area and the data is stored in the designated area, the length of the read data is read. If it exceeds the range of the specified divided area, the read data is stored by the drive means for rounding and storing the exceeded data from the beginning of the specified divided area and a plurality of divided areas. When a data read request is issued from the buffer memory and the higher-level device, the read range of the data registered in the optical disc to the drive means and the specific divided area of the buffer memory are designated and data is designated. A buffer control device having an interface means for issuing a read instruction and storing the read data in a specific divided area of the buffer memory It is.

According to another aspect of the present invention, when there is a read request for the data registered in the optical disc from the host device, the data related to this read request hits the buffer memory consisting of a plurality of divided areas. If it hits, it is read from the buffer memory and sent to the host device. On the other hand, if the data related to the read request does not hit the buffer memory, the read request is sent from the optical disk. There is obtained a buffer control method in which data is read in the read range according to the above and is stored in a specific divided area of the buffer memory.

[0009]

According to the buffer control device of the present invention, when a data read request is issued from the host device, the interface means and the read range and buffer relating to the read request of the data registered in the optical disk with respect to the drive means. The data reading is instructed by designating a specific divided area of the memory, while the drive means stores the read data in the specified specific divided area of the buffer memory.

The divided area is designated so as not to overlap with the divided area in which data is already stored. Further, as a dynamic storage medium other than the optical disc, there is a magnetic disc storage medium, but in any case, when the buffer control device and the buffer control method according to the present invention are used, the read speed is slower than that of a buffer memory made of a semiconductor. It is expected that the reading speed of the dynamic storage medium will be improved.

Further, according to the present invention, when there is a data read request from the host device, the interface means reads the data corresponding to the read request stored in the buffer memory and transmits the data to the host device.
On the other hand, if the data related to the read request is not stored in the buffer memory, the drive unit is instructed to read the data and the read data is stored in one divided area of the buffer memory.

Further, in the buffer control device of the present invention, when there is a data read request from the host device and the data is read from the optical disc, the drive means reads the data registered in the optical disc within a specified range, and this data is read. When storing the data in the specified area, if the length of the read data exceeds the range of the specified divided area, the exceeded data is rounded from the beginning of the specified divided area and stored. . As a result, when the read data is long, it is overwritten in the range of the divided area many times, so that this data is not stored in other divided areas.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 3 shows the configuration of an image filing device to which the buffer control device according to the present invention is applied. This image filing device includes a control module 6
0, memory module 61, image processing module 62, communication control module 63, scanner device 55, keyboard 31, CRT display device 44, printer device 5
6, the magnetic disk 34 and the magnetic disk device 33, the mouse 32, the system bus 38, the image bus 46, the character recognition unit 45, and the optical disk 15 and the optical disk device 12 according to the present invention.

The control module 60 connects the CPU 30 for performing various controls such as image storage, retrieval, and edit processing on the optical disk 15, the optical disk device 12, and the magnetic disk device 33 to the CPU 30, and the CP.
It is composed of an interface control unit 13 that gives an instruction to read optical disk data to the magnetic disk device 33 using the function of U30. A keyboard 31 and a mouse 32 are connected to the CPU 30.

The memory module 61 is a main memory 40 for storing various control programs for image storage, retrieval, editing, etc., management information, etc., a character recognition section 45 for recognizing the characters of the image, and several pages of A4 size document. A page memory 41 as an image memory having a storage capacity corresponding to an image,
A display memory 42 as a display interface, a display control unit 43, and the like are included. An area of the buffer memory 14 is provided in a part of the page memory 41. The page memory 41 is, for example, the optical disc 15
Is a memory for temporarily storing the image data stored in the optical disk 15 and the image data read from the optical disk 15, and the buffer memory 14 is a memory for temporarily storing the data read from the optical disk 15.

The display memory 42 is for temporarily storing an image displayed by the CRT display device 44. The display control unit 43 controls the display processing of the CRT display device 44 and the like.

The image processing module 62 includes an enlarging / reducing circuit 51 for enlarging and reducing an image, a vertical / horizontal converting circuit 52 for rotating an image, a compression / decompression circuit (CODEC) 50 for compressing / decompressing an image, and a scanner device. The scanner interface 53 for the printer 55, the printer interface 54 for the printer device 56, and the scaling circuit 5 described above.
1 and the vertical / horizontal conversion circuit 52, the compression / expansion circuit 50, the scanner interface 53, and the printer interface 54.

The compression / expansion circuit 50 is a MH (Modified Huff).
Band compression or band expansion is performed using a man (man) method, an MR (Modified Read) method, or the like. The communication control module 63 is configured by a communication interface 17 such as a BCP (Bus Communication Processor) connected to a communication line such as a local area network (Local Ared Network), and the host computer 11 is connected via this communication line. ing. Further, the communication control module 63 is connected to an external device such as an FCP (facsimile connection mechanism) or a personal computer through an interface, and a UCP (Universal Communication P).
rocessor) may be provided.

The system bus 38 is a bus for control signals of various devices and connects the control module 60 to the memory module 61, the image processing module 62, and the communication control module 63. The image bus 46 is an image bus, and connects the memory module 61, the image processing module 62, and the communication control module 63.

The scanner device 55 is, for example, a two-dimensional scanning device and obtains an electric signal corresponding to an image on the original by scanning the original (document) two-dimensionally with a laser beam.

The optical disk device 12 is for sequentially storing the images read by the scanner device 55 in the optical disk 15, and also searches the optical disk 15 for an image corresponding to a search code designated by the keyboard 31 or the like. It is a thing.

The keyboard 31 is used to input a unique search code corresponding to an image stored in the optical disk 15 and various operation commands for storage, search, edit processing and the like. In addition, the mouse 32 moves the cursor (not shown) displayed on the display window of the CRT display device 44, for example, vertically and horizontally, and gives an instruction at a desired position so that the cursor is positioned. The display contents are selected or instructed.

The CRT display device (cathode ray tube display device) 44 displays the image read by the scanner device 55 and the image retrieved from the optical disk 15. Icons and the like are displayed at the upper end, the lower end, and the right end on the display window of the CRT display device 44.

The printer device 56 prints out (hardcopy) the image read by the scanner device 55, the image retrieved from the optical disk 15 or the image displayed on the CRT display device 44.

The magnetic disk device 33 stores various control programs on the magnetic disk 34 mounted on the magnetic disk device 33, and stores a search code input from the keyboard 31 and an image corresponding to the search code. It stores search data (search information) including a storage address on the optical disc 15, an image size, a search frequency, and the like.

The search data is managed by a document management table. In this document management table, one document number corresponding to each search code (image name) consisting of a plurality of search keys is stored. A title management table 35, a page management table 36 in which record numbers are stored in page units of one document, a storage address (storage start position) of an image on the optical disk 15 for each record number, a document size (image size), Image attributes such as compression method and resolution, and search frequency (access frequency)
Is stored in the record management table 37.

The above-mentioned storage address is a logical address, and the physical track address and physical sector address are calculated from this at the time of access.

The character recognizing unit 45 performs character recognition on the dot image data of the image, converts it into a character code, and outputs it. For example, one line unit of the image data stored in the page memory 41 is taken out and recognized for each character. As a result, the character code for searching when performing the character search is output.

As a storage process of image data in the image filing apparatus having the above-mentioned configuration, for example, the registration mode is selectively set by the keyboard 31. Next, the document is set on the scanner device 55, and the CPU 30 operates the optical disk device 12 and the scanner device 55. The scanner device 55 two-dimensionally scans an image of a set document or the like to perform photoelectric conversion, and the line information of the photoelectrically converted image is sequentially stored in the page memory 41. The image stored in the page memory 41 is displayed in the display memory 42.
The display contents of the display memory 42 are stored in the display control unit 4.
3 is displayed on the CRT display device 44.

Next, the search code of the image stored in the optical disk 15 is input. This search code is composed of a plurality of search keys, and the contents of the items of this search key are preset. CPU
30 checks the validity of the input search code and compares it with the search code registered in the optical disk 15 to check the double registration. Depending on the result of this check, the entered search code is stored in the main memory 40.
Be registered with.

When the displayed image is satisfactory, a memory key (not shown) is input. Then the CPU
In the compression / expansion circuit 50, the image 30 stored in the page memory 41 is subjected to band-compression by the compression / expansion circuit 50 by a well-known MR method or the like to perform encoding processing. The encoded image is supplied to the optical disc device 12 and registered in the optical disc 15.

If there is a read request from the host computer 11 connected to this apparatus via a communication line, the data registered in the optical disk 15 in this way is the data related to this read request. Is read from and is transmitted to the host computer 11.

At that time, in order to increase the reading speed, a so-called cache memory method is used in which a part of the data registered in the optical disk 15 is stored in the buffer memory 14, but in this embodiment, the buffer memory 14 is used. Is divided into a plurality of areas, and the optical disk 1 is divided into units.
It was decided to store the data read from No. 5. As shown in FIGS. 5A and 5B, the buffer memory 14 is divided into, for example, N divided areas 1 to 2 to N, and each divided area is used as one storage unit in the optical disc. The data read from 15 is stored.

FIG. 4 shows only a processing element related to the management of the buffer memory 14 from the image filing apparatus shown in FIG. This buffer control device 16
It is connected to the host computer 11 (corresponding to the host device 1) via the command communication path 20 and the data communication path 23. The device 16 includes a communication interface 17 for controlling communication with the host computer 11, a buffer memory 14 whose area is divided into N divided areas,
An optical disk device 12 that searches for and reads out data instructed to be read from the optical disk 15 in which various data such as image data is registered and stores the data in the buffer memory 14.
It has an interface control unit 13 (corresponding to the interface unit 3) (corresponding to the drive unit 2) and an instruction for reading data from the optical disk device 12 using the functions of the CPU 30.

The communication interface 17 and the interface controller 13 are connected via a command communication path 20 and a data communication path 23, and the interface controller 13 and the optical disk device 12 are connected via a drive control communication path 21. Connected. Further, the optical disk 15 and the optical disk device 12 and the optical disk device 12 and the buffer memory 14 are connected via a data read path 22.

The operation of the buffer controller 16 when the host computer 11 makes a read request will now be described. When a read request command is output from the host computer 11, this command is sent to the buffer control device 16 via the command communication path 20. Then, the communication interface 1 provided in the device 16
7, and this command is sent to the interface control unit 13.

The interface control unit 13 having received the above command judges whether or not the read request range of the data designated by this command is hit in the buffer memory 14, and if it is hit, it is judged from the buffer memory 14. The corresponding data is read and the data communication path 23
This data is transmitted to the host computer 11 via.

On the other hand, if the buffer memory 14 is not hit, the logical block address of the optical disk 15 for reading the data requested by the command, the read data length, and the address of the divided area of the buffer memory 14 are read through the drive control communication path 21. Optical disc device 1 with designation
2 is instructed to read data. In designating this divided area, for example, an empty divided area or a divided area in which data that is read infrequently is held is specified.

Then, the optical disk device 12 reads the data in the specified range from the optical disk 15, and passes the read data through the data read path 22 to the buffer memory 14.
It is stored in the specified divided area of.

The example of FIG. 4 shows that the data read from the optical disk 15 is stored in the divided area of the buffer memory 14 having the number 1.

In the example of FIG. 5A, when the data is read from the optical disk 15, the read data length for instructing the optical disk device 12 to read the data from the optical disk 15 has a read data length of the divided area of number 1 of the buffer memory 14. It shows how data is stored when the size is equal to or shorter than the size. In this case, since the read data can be stored in the divided area with the number 1, the data in the divided areas with the numbers 2 to N in the buffer memory 14 are stored as they are.

In the example of FIG. 5B, when the data is read from the optical disk 15, the read data length for designating the data read from the interface control unit 13 to the optical disk device 12 is the divided area of the number 1 of the buffer memory 14. It shows how data is stored when it is longer than the size. In this case, since the read data cannot be stored in the divided area of number 1, the data is stored while returning to the head address of this divided area and rounding the divided area. Therefore, the data in the divided areas numbered 2 to N in the buffer memory 14 are stored as they are.

Therefore, according to the above-described embodiment, when a data read request is issued from the host computer 11, if the data associated with the read request hits the buffer memory 14, it is read and sent to the host computer 11. On the other hand, the data related to the read request is the buffer memory 1
If 4 is not hit, the data read from the optical disk 15 is stored in one divided area of the buffer memory 14. Therefore, if the data related to the read request hits the buffer memory 14, the reading speed is high. In addition, since the data read from the optical disk 15 is stored in the divided areas of the buffer memory 14, it is expected that the read speed will be improved in the subsequent read requests.

Further, in the optical disk device 12, when the length of the data read from the optical disk 15 exceeds the range of the specified divided area, the exceeded data is rounded from the head of the specified divided area and stored. Therefore, regardless of the size of the read range related to the data read request from the host computer 11, the data is stored in only one divided area, and the data stored in the other divided areas remains unchanged. Since the data is stored, the hit rate of the entire buffer memory 14 can be improved.

[0046]

As described above in detail, according to the buffer control device of the present invention, the interface means specifies the read range and the buffer memory according to the read request of the data registered in the optical disk to the drive means. Since the configuration is adopted in which the data read instruction is made by designating the divided areas of the data, the interface means can easily manage the data stored in the buffer memory and improve the read speed at the time of subsequent read requests. Be expected.

Further, according to the buffer control device or the buffer control method of the present invention, when a data read request is issued from the host device, if the data related to the read request hits the buffer memory, the data is read. If the data related to the read request does not hit the buffer memory, the data read from the optical disk is stored in a specific divided area of the buffer memory, so the read speed becomes faster. At the same time, it is expected that the read speed will be improved in the subsequent read requests.

Further, according to the buffer control device of the present invention, when the length of the data read from the optical disc exceeds the range of the designated divided area, the drive means designates the exceeded data. Since the divided areas are stored in a round form from the beginning, regardless of the size of the read range related to the data read request from the higher-level device, the data is stored only in a specific divided area. Since the data stored in is stored as it is, the hit rate of the buffer memory can be improved.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a buffer control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of a buffer control method according to an embodiment.

FIG. 3 is a block configuration diagram of an image filing device according to the present invention.

FIG. 4 is a block configuration diagram of a buffer control device according to an embodiment.

5A and 5B are explanatory diagrams for storing read data in a buffer memory according to an embodiment, FIG. 5A is a diagram showing a storage state when data is shorter than a divided area, and FIG. 5B is read data. FIG. 6 is a diagram showing a storage state when is longer than a divided area.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Host device, 2 ... Drive means, 3 ... Interface means, 12 ... Optical disk device, 13 ... Interface control part, 4 ... Buffer memory, 5 ... Optical disk.

Claims (4)

[Claims] 1. A buffer memory comprising a plurality of divided areas, a read storage means for reading data registered in an optical disk in a designated range and storing the data in a predetermined area of the buffer memory, When a data read request is made, it has means for reading and storing data by designating the read range of the data registered in the optical disc to the read storage means according to the read request and a specific area of the buffer memory. A buffer control device characterized by: 2. A drive means for reading data registered on an optical disk in a designated range and storing the data in a designated area, and a buffer comprising a plurality of divided areas for storing the read data. At the time of a data read request from the memory and the host device, if the data related to the read request hits the buffer memory, it is read and transmitted to the host device, while the data related to the read request is sent to the buffer memory. If it does not hit, the data read instruction is performed by designating the read range related to the read request of the data registered in the optical disc to the drive means and the specific divided area of the buffer memory, and reading the read data. A buffer control device having interface means for storing the data in a specific divided area of the buffer memory. 3. When the data registered on the optical disk is read in a designated area and the data is stored in the designated area, the length of the read data is set in the designated divided area range. If it exceeds, a drive means for rounding and storing the exceeded data from the beginning of the specified divided area, a buffer memory composed of a plurality of divided areas for storing the read data, and a host device When the data read request is issued, the read data is instructed to the drive means by designating the read range of the data registered in the optical disk according to the read request and the specific divided area of the buffer memory, and the read data is read. A buffer control device having interface means for storing the data in a specific divided area of the buffer memory. 4. When a read request for data registered in the optical disc is issued from the host device, it is checked whether or not the data related to the read request hits a buffer memory composed of a plurality of divided areas. If there is a hit, it is read from the buffer memory and transmitted to the host device. On the other hand, if the data related to the read request does not hit the buffer memory, the data is read from the optical disk within the read range related to the above read request, A buffer control method characterized by storing this in one divided area of the buffer memory.