JPH0452923A - Data input/output system - Google Patents

Abstract

PURPOSE:To increase the data access speed by providing a compressing/ expanding means which compresses/expands data between an image memory and a first-in first-out FIFO buffer and a transfer control means which transfers the data between the FIFO buffer and an auxiliary storage means. CONSTITUTION:When the data in an image memory 1 is compressed and written in an auxiliary storage device 5, an image compressing/expanding part 2 successively takes out the data from the image memory 1 and compresses it to store it in a buffer memory 3 by the instruction from a control part 6. In parallel with this operation, the control part 6 searches a free area of the auxiliary storage device 5 based on file management information in a file information storage part 7 to determine a write area and sends the write indication to an auxiliary storage device control part 4. This control part 4 successively writes the compressed data, which is written in the buffer memory 3, in the designated area of the auxiliary storage device 5. Thus, the data access speed is increased.

Description

TECHNICAL FIELD The present invention relates to a data input/output system, and more particularly to an image data input/output system between an auxiliary storage device such as a hard disk or magneto-optical disk and an image memory in an image filing device.

BACKGROUND OF THE INVENTION In general, when files are repeatedly created and deleted from an auxiliary storage device, empty storage areas become scattered and not continuous. For this reason, conventionally, when manually outputting data from an auxiliary storage device, the access size of the auxiliary storage device is set to a fixed length (for example, in units of sectors or clusters), and even if continuous areas within the auxiliary storage device are Even when used, input/output processing is performed independently for each fixed length.

Also, when compressing data and recording it in auxiliary storage,
Since the size of the data to be recorded cannot be determined unless it is compressed, a method is adopted in which the data in memory is compressed into another buffer memory and then written to the auxiliary storage device. On the other hand, when reading compressed data recorded in an auxiliary storage device, the method is to first read the compressed data from the auxiliary storage device to a buffer memory, then decompress it and transfer it to another memory. ing.

However, with the conventional data input/output method described above, when handling large data such as image data, processing is performed in fixed-length access size units even when accessing physically contiguous areas in the auxiliary storage device. It has the disadvantage that the access speed decreases because it is divided and cannot perform continuous input/output.

Also, when decompressing compressed data recorded in the auxiliary storage device and expanding it onto the image memory, and when compressing data on the image memory and writing it to the auxiliary storage device, input/output with the auxiliary input/output device is performed. The disadvantage is that the data compression/decompression processing cannot be performed in parallel.

Furthermore, a buffer memory is required to store a portion of the compressed data, and when handling large data such as image data, this buffer memory has a large capacity.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and its purpose is to provide a data input/output system that can access data faster.

Structure of the Invention The data input/output system according to the present invention comprises an image memory for storing image data, an auxiliary storage means for storing compressed data of the image data, and a data input/output system provided between the image memory and the auxiliary storage means. a first-in, first-out buffer, and compression/decompression means for compressing and decompressing data between the image memory and the first-in, first-out buffer;
It is characterized by comprising a transfer control means for transferring data between the first-in first-out buffer and the auxiliary storage means.

Another data input/output system according to the present invention includes an image memory that stores image data, and an auxiliary device that stores compressed data of the image data in separate areas and that can be read independently for each of the predetermined areas. storage means; a first-in first-out buffer provided between the image memory and the auxiliary storage means; a compression/decompression means for compressing and decompressing data between the image memory and the first-in first-out buffer; and the auxiliary storage means. management information storage means for storing storage management information indicating whether or not there is an area that can be continuously accessed out of a predetermined area in which the data in the data is divided and stored; When the storage management information indicates that there is an accessible area,
It is characterized by comprising transfer control means for transferring these areas between the auxiliary storage means and the first-in first-out buffer.

Example Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of a data input/output system according to the present invention.

In the figure, an image memory 1 is a memory for storing image data, and a semiconductor memory is used for this.

The image compression/decompression section 2 takes out the image data stored in the image memory 1, compresses it, and stores it in the buffer memory 3, and also decompresses the compressed data written in the buffer memory section 3 and transfers it to the image memory section 1. This is the part that processes writing to.

The FIFO (first in, first out) type buffer memory 3 is a memory for time storage in which data can be read out in the order in which they are written.

The auxiliary storage device control unit 4 is a part that controls the output of image data compressed between the auxiliary storage device 5 and the buffer memory 3 using DMA (formerly rect memory access), and allows continuous multiple data accesses. Units can be input and output at once.

The auxiliary storage device 5 is a part that stores compressed image data, and corresponds to a hard disk or a magneto-optical disk.

The control unit 6 includes an image compression/decompression unit 2 and a buffer memory 3.
This is a part that controls the operation and processing timing of the auxiliary storage device control section 5.

The file information storage section 7 stores information in the auxiliary storage device 5 before accessing the file information storage section 7.
This is a part that stores information (file management information) regarding the usage area, data storage area, size of stored data, etc. in the auxiliary storage device 5, which has been read out in advance from the auxiliary storage device 5. By referring to the information in this file information storage section 7, it can be determined whether or not there is a physically continuous storage area in the auxiliary storage device 5.

The control signal line 8 is a signal line through which the control section 6 controls the input/output of the image compression/expansion section 2, the buffer memory 3, and the auxiliary storage device control section 4.

Next, the operation of each part of the system configured as described above will be explained.

The data in the image memory 1 is compressed and stored in the auxiliary storage device 5.
When writing data to the image memory 1, upon receiving an instruction from the control unit 6, the image compression/expansion unit 2 sequentially extracts data from the image memory 1.
This is compressed and stored in the buffer memory 3. In parallel with this, the control unit 6 searches for an empty area in the auxiliary storage device 5 based on the file management information in the file information storage unit 7,
The area to be written is determined and a write instruction is sent to the auxiliary storage device control unit 4. The auxiliary storage device control unit 4 sequentially writes the compressed data written in the buffer memory 3 to a designated area of the auxiliary storage device 5.

The above write operation will be explained using the flowchart of FIG.

First, the control unit 6 sets the transfer direction for the buffer memory 3 (step 31). Thereafter, data is read from the image memory 1, compressed by the image compression/expansion section 2, and then stored in the buffer memory 3 (step 32).

Next, the auxiliary storage device control unit 4 reads the compressed data from the buffer memory 3 and starts writing it to the auxiliary storage device 5 (step 33). Thereafter, the process continues until all data has been written (step 34→3).
1→...).

Returning to FIG. 1, when reading compressed data written in the auxiliary storage device 5 to the image memory 1, the control unit 6 reads out the area to be read from the file management information stored in the file information management unit 7. information, and sends a read instruction to the auxiliary storage device control section 4. Auxiliary storage control unit 4
reads the compressed data from the auxiliary storage device 5 and stores it in the buffer memory 3. In parallel with this, the control section 6 sends a data expansion instruction to the image compression/expansion section 2.

The image compression/expansion section 2 takes out compressed data from the buffer memory 3, decompresses it, and inputs it into the image memory section 1.

The above read operation will be explained using the flowchart of FIG. 2.

First, the control unit 6 sets the transfer direction for the buffer memory 3 (step 21). Thereafter, the auxiliary storage device control unit 4 starts reading the compressed data from the auxiliary storage device 5 and sequentially stores it in the buffer memory 3 (step 22).

Next, the image compression/expansion section 2 decompresses the data in the buffer memory 3, and writes the decompressed data into the image memory (step 23). Thereafter, the process continues until all data has been read (step 24-2).
1→...).

In each of the above operations, the buffer memory 3 temporarily stores data so that the auxiliary storage device control section 4 and the image compression/expansion section 2 can perform their respective processes in parallel asynchronously. This allows the auxiliary storage device control section 4 and the image compression/expansion section 2 to perform processing in parallel.

Also, check whether there is a timing when the data flow is interrupted for each input/output unit of the auxiliary storage device 5, or whether the buffer memory 3
stores some data, so the image compression/decompression unit 2
can process data continuously. Therefore, the overall processing time can be shortened and the apparent processing speed can be improved. Note that since the buffer memory does not need to accommodate all of the image data, its capacity can be small.

By the way, the storage capacity of the buffer memory 3 depends on the access speed of the auxiliary storage device 5 and the compression/expansion section 2.
It must be determined taking decompression processing speed into consideration. Generally, processing efficiency is good if the following relationship holds.

Buffer memory storage capacity [bytes] ≧ Auxiliary storage device delay [bytes/second] × Access time [seconds] Note that the auxiliary storage device delay is the expected maximum delay of the auxiliary storage device with respect to the image compression/decompression section, Access time is the expected maximum time for auxiliary storage access time.

Furthermore, when accessing the auxiliary storage device 5, the control unit 6 preliminarily transfers the data from the auxiliary storage device 5 to the auxiliary storage device control unit 4 before accessing the auxiliary storage device 5 so that the physically continuous storage area within the auxiliary storage device 5 can be input/output. control and read file management information,
It is held in the file information storage section 7.

When accessing the auxiliary storage device 5, the control section 6 checks from the file management information stored in the file information storage section 7 whether or not the area to be accessed is continuous. As a result, if there are a plurality of consecutive access size units, an instruction is given to the auxiliary storage device control unit 4 to input/output the plurality of consecutive access size units at once.

In this way, by inputting and outputting multiple consecutive access size units at once, the time required for sending and receiving control signals between devices and calculating address values, that is, the overhead, can be reduced and access speed is improved. .

Note that if a plurality of consecutive access size units does not exist in the area to be accessed, access is performed in fixed length access units as in the past.

When reading compressed data from the auxiliary storage device 5, the control unit 6 checks the number of file access units to be read from the file management information and whether or not each file access unit is continuous.

On the other hand, when compressing and writing data to the auxiliary storage device 5,
Since the size after compression is not known before compression, the controller 6
determines the upper limit of the continuous access unit to be written to the auxiliary storage device 5 based on the data size before compression. Then, a write instruction is issued to the auxiliary storage device control unit 4 for each consecutive access unit below this upper limit, and after the image data compression/expansion unit 2 detects the completion of compression of all the image data, the control unit 6 Waiting until the data is output from the buffer memory 3 to the auxiliary storage device control section 4, it issues an instruction to the auxiliary storage device control section 4 to stop writing.

Next, the fifth section describes the operation at the end interrupt of the auxiliary storage device.
This will be explained using figures. When the auxiliary storage device end interrupt occurs, it is determined whether read processing or write processing is still necessary (steps 51→52).

If any processing is required, the next auxiliary storage device read or write processing is started (steps 52-+53
).

If neither read processing nor write processing is necessary, it is determined whether the end flag (not shown) for the image compression/expansion section is "end" (steps 52→54). If “Finish”, all processing is finished (step 5).
4 to 56), otherwise sets an end flag (not shown) for the auxiliary storage device to "end" (steps 54-55).

In addition, the operation at the end interrupt of the image compression/decompression section is as follows.
It will look like the figure. When the end interrupt of the image compression/decompression unit occurs, it is determined whether the end flag (not shown) for the auxiliary storage device is "end" (step 6l-62).
. If it is "end", all processing ends (steps 62-64); otherwise, an end flag (not shown) for the image compression/expansion section is set to "end" (steps 62-63).

In other words, when the end flag for the auxiliary storage device and the end flag for the image compression/expansion section become "end", all processing ends.

Next, a description will be given of processing when the buffer memory 3 becomes full during read processing or write processing. In this case, the buffer memory 3 is generally composed of multiple stages of D-type flip-flops connected in cascade, and whether or not each flip-flop has free space can be monitored using hardware.

Therefore, in the flowchart of FIG. 4, when the system power is on, it is always monitored whether the buffer memory 3 is full (steps 41-42).
→41...). If the buffer memory 3 is full, control is performed to stop reading from the transfer source to the buffer memory 3 (steps 42-43).

The stopped state continues until there is space in the buffer memory 3 (steps 44→43→44, etc.). When a free space is available, it is again monitored whether the buffer memory 3 is full (steps 44-41-42, . . . ).

That is, according to the present invention, a first-in, first-out buffer memory is provided between the auxiliary storage device control section and the image compression/expansion section, which is capable of bidirectional data transfer using the DMA method, and which can store time data. This allows the auxiliary storage device control section and the image compression/expansion section to perform their respective processes separately and in parallel, improving processing speed. Furthermore, since the data can be processed in parallel, it is not necessary to store all the image data in the buffer memory, and the memory capacity can be reduced. Furthermore, in the auxiliary storage device, input/output is performed for each data size, so there are times when the data flow is interrupted, but since some data can be stored in the buffer memory, the image compression/decompression section continues. This allows data to be input and output using the same method, increasing overall speed.

Note that in this embodiment, in addition to improving access speed by performing processing on the input end and output side of the buffer memory in parallel, continuous storage areas in the auxiliary storage device are accessed all at once. Although we aim to improve access speed by using only one method,
It is clear that access speed can be improved.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a first-in, first-out buffer memory section between the auxiliary storage device control section and the image compression/expansion section, and connects the auxiliary storage device control section and the image compression/expansion section. The image compression/decompression section can perform its respective processes in parallel, and the image compression/decompression section can input and output data continuously regardless of the input/output timing of the auxiliary storage device. This has the effect of reducing time and apparently improving processing speed. Furthermore, since the buffer memory does not need to accommodate all of the image data, it has the advantage that its capacity can be small.

Furthermore, the control unit reads the file management information from the auxiliary storage device in advance and stores it in the file information storage unit before accessing the auxiliary storage device, and when accessing the auxiliary storage device, the control unit reads the file management information from the auxiliary storage device. Since the auxiliary storage device control unit is controlled so that continuous storage areas can be input/output at once, there is also the effect that the time required for data input/output can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a data input/output system according to an embodiment of the present invention, FIG. 2 is a flow chart showing the read processing procedure, FIG. 3 is a flow chart showing the write processing procedure, and FIG. FIG. 5 is a flowchart showing the operation of the auxiliary storage device at the time of termination interrupt, and FIG. 6 is a flowchart showing the operation of the image compression/expansion unit at the time of termination interrupt. Explanation of symbols of main parts 1...Image memory 2...Image compression/expansion unit 3...Buffer memory 4...Auxiliary storage device control unit... ... Auxiliary storage device 6 ... ... Control section 7 ... File information storage section

Claims (2)

[Claims] (1) An image memory for storing image data, an auxiliary storage means for storing compressed data of the image data, a first-in first-out buffer provided between the image memory and the auxiliary storage means, and an image memory for storing the image data. A data input device comprising: compression/expansion means for compressing/expanding data between a memory and the first-in, first-out buffer; and transfer control means for transferring data between the first-in, first-out buffer and the auxiliary storage means. output system. (2) an image memory that stores image data; an auxiliary storage means that divides and stores compressed data of the image data in predetermined areas, and that can read each predetermined area independently; and the image memory; A first-in, first-out buffer provided between the auxiliary storage means, a compression/expansion means for compressing and decompressing data between the image memory and the first-in, first-out buffer, and data in the auxiliary storage means is divided and stored. management information storage means for storing storage management information indicating whether or not there is an area that can be accessed consecutively among the predetermined areas that have been accessed; A data input/output system comprising: transfer control means for transferring those areas between said auxiliary storage means and said first-in first-out buffer when said storage management information indicates.