JP3414130B2 - Real-time data storage device and write / read method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for writing / reading real-time data such as video data and audio data to / from a replaceable storage medium, and more particularly, when the storage medium is replaced. The present invention relates to a technique for performing optimum access processing to the storage medium.

[0002]

2. Description of the Related Art In a data storage device capable of writing / reading data in real time, write / read access to a storage medium has been performed at a fixed rate. Examples of such a storage medium include a video tape for recording / reproducing audio data and video data, an MD (mini disk) for recording / reproducing audio data, and the like.

In addition, with the development of data compression technology and cost reduction of storage media, storage media such as hard disk drives (HDD) and flash memories that have been used mainly in computers in the past are used as real-time data such as video data and audio data. The use for writing / reading data is being put to practical use.

[0004]

However, since the hard disk drive, flash memory, and the like are not created in consideration of real-time read / write / read, the access rate varies greatly depending on the model. Further, in a hard disk drive, there may be a large variation in access rate depending on the area even within the same disk. Furthermore, for hard disk drives, users can purchase bare drives for expansion or replacement, but if the system has a fixed data access rate, the advantage of using alternative storage media cannot be utilized.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an apparatus and method for performing optimum access processing to a storage medium when the storage medium is replaced.

[0006]

In order to solve the above-mentioned problems, a real-time data storage device according to the present invention comprises a data storage device containing a replaceable storage medium and a control block. The control block has means for evaluating the writing / reading capability of the storage medium, and the writing / reading capability is the maximum transfer rate per unit time for a continuous area of the storage medium. A real-time data storage device according to the present invention includes a data storage device having a replaceable storage medium built therein and a control block, and the control block evaluates the write / read capability of the storage medium. Have means,
The writing ability and the reading ability are evaluated, and the one that is not larger is used as an evaluation value, and writing / reading is performed based on the evaluation value.

The real-time data writing / reading method according to the present invention evaluates the writing / reading ability of a storage medium built in a data storage device and configured to be replaceable, so that the continuous area of the storage medium can be read per unit time. It is characterized in that the maximum transfer rate is set to the writing / reading capability. The real-time data writing / reading method according to the present invention evaluates the writing and reading capabilities of a replaceable storage medium built in a data storage device, and sets the evaluation value to the one that is not greater than the evaluation value. It is characterized in that writing / reading is performed on the basis of.

According to the present invention, when the storage device is activated, it is determined whether or not the writing / reading ability is stored in a predetermined area of the storage medium, and if not, the writing / reading ability is evaluated. Writing / reading is performed based on the evaluation result.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a data storage system to which the present invention is applied. This system is based on JPEG (Joint Photo).
Image data compressed by the Graphic Experts Group method and audio data quantized by 16 bits are recorded on a disc.

As shown in FIG. 1, this data storage system includes a data supply device 1, a control block 2 connected to the data supply device 1, a data storage device 3 and a data reproduction device 4 connected to the control block 2. It consists of and.

The data supply device 1 supplies the image data compressed by the JPEG system and the audio data quantized with 16 bits to the control block 2.

JPEG is one of the image compression algorithms and has the characteristic that an image is compressed in field units and the amount of data generated in each field after compression can be varied within a certain range. In this system, control block 2
The target value of the data generation amount after compression can be set by the control of the CPU 21 inside. As a result, the data supply device 1 performs compression so that the data generation amount falls below the target value.
However, this does not guarantee that the amount of generated data will completely fall below the target value.

In accordance with a control signal from the CPU 21 in the control block 2, the data storage device 3 writes the data supplied from the control block 2 to a designated area of the built-in disc or designates the disc. It has a function to read data from the area and transfer it to the control block 2. The disk block built in the data storage device 3 can be replaced and used as needed. And write /
Various disk blocks with different read transfer rates can be used.

The data reproducing device 4 separates the video data and the audio data supplied from the control block 2, and further decodes the analog data to reproduce it.

The control block 2 comprises a CPU 21, a data selector 22, and a data storage device interface 23.

The CPU 21 manages the system by control signals and monitors the system status. It has an internal memory and saves data as needed.

The data selector 22 transfers either the data from the data supply device 1 or the data from the data storage device 3 to the data reproduction device 4 in response to a control signal from the CPU 21.

The data storage device interface 23 is C
Under the control of the PU 21, data is transferred to and from the data storage device 3 and some control signals are exchanged. Data storage device interface 2 from CPU 21
By specifying the write address, the write data size, and the write / read section to 3, the data storage device interface 23 can autonomously exchange data. Further, it is possible to autonomously generate specific data by the setting of the CPU 21 and write it to the disc.

Now, the operation after the power is turned on to the system is as shown in FIG. That is, after the power is turned on, the CPU 21
Reads the data of the area that is set as software by the system as the management data recording area in advance,
It is determined whether system management data is recorded (steps S1 and S2). The recorded management data includes the average data write / read capability value (data transfer rate) of the disk unit incorporated in the data storage device 3 for one field period.

If the management data is recorded, the target value of the data supply device 1 is set so that the amount of data generated by the data supply device 1 falls within a small value of the write rate and the read rate (step). S3, S
4). If the management data is not recorded, the writing / reading capability of the data storage device 3 is tested (step S5).

The system prerequisites for the data storage device 3 will now be described. First, the disk in the data storage device 3 has a predetermined access unit for writing / reading, and this is called an address. Second, the storage capacity and the number of addresses of the disk are determined by the CPU 21
Can be acquired from the data storage device 3 every time.

A test method for writing / reading capability is shown in FIG. As shown in this figure, when the CPU 21 sends a data write / read address, write / read data amount, write / read classification, and a test bit valid signal indicating the start of the write / read test to the data storage device interface 23. The data storage device evaluation circuit 231 in the data storage device interface 23 starts the transfer rate test.

More specifically, the CPU 21 sets a data set regarding a data write / read address, a write / read data amount, and a write / read section in a register (not shown) in the data storage device evaluation circuit 231. This dataset is C
Although the default numerical values are set in the ROM (not shown) inside the PU 21, it is possible for the user to reset the numerical values later.

In the data write / read address of the data set, all the previously acquired addresses of the disk are evenly divided to create a plurality of continuous address areas, and the value of the head address is given. If it cannot be divided evenly, the area is divided so that the number of addresses is as small as possible. Although the default number of areas is stored in the ROM inside the CPU 21, it can be set by the user. A default value for the write / read data amount is also stored in the ROM, but it can be changed later by the user. The default value is the typical amount that the system is expected to write / read per second.

For example, if the disk in the data storage device 3 is 1
It is assumed from the acquired data that it has a storage capacity of G bytes and has one address for each 1 Mbyte. C
It is assumed that the PU 21 divides the disk area into 10 areas, and uses the start address 0, 100, 200, ..., 900 as a data set write / read address to write / read about 2 Mbytes of data per second. Then, write to the register together with write / read designation.

First, when the CPU 21 specifies the test of the writing ability (step S11), the data storage device interface 23 autonomously generates data from the internal data storage device evaluation circuit 231 and specifies it from the specified address. The written amount of data is written to the disk of the data storage device 3 at the maximum speed (step S1).
2). When the writing is completed, the time required for writing is calculated and the value is transmitted to the CPU 21 (steps S13 and S14).

Next, when the CPU 21 designates a read capability test (step S15), the data storage device evaluation circuit 231 reads out a designated amount of data from a designated address of the disk at the maximum speed ( Step S16). After all reading is completed (step S17), the time required for reading is calculated and the value is transmitted to the CPU 21 (step S18).

The CPU 21 compares the write rate calculated in step S14 with the read rate calculated in step S18, and sets the target value of the data supply device 1 so that the data is supplied so that the rate is not higher. Is performed (step S4 in FIG. 2).

After the target value is set and the other settings are completed as described above, the system shifts to a steady state. As shown in FIG. 2, the steady state has three states, that is, a simple recording state, a simple reproducing state, and a simultaneous recording / reproducing state, and shifts to another state according to a command from an external remote controller or the like, or the state of the system. .

In the simple recording state, the system writes the data from the data supply device 1 to the disk of the data storage device 3 and transfers it to the data reproduction device 4. During this time, C
The PU 21 constantly monitors the amount of supplied data in 1-field units from the control signal from the data supply device 1. And
When data that exceeds the target value set by the CPU 21 is generated, the image data from the data supply device 1 is controlled by the control signal to the data storage device interface 23 until the data amount of the difference from the target value can be written. Do not write to the data storage device 3. On the other hand, audio data is continuously written.

In the simple reproduction state, the system reads out a predetermined amount of data from the address designated by the CPU 21 for each field and transfers it to the data reproducing device 4. During this time, the CPU 21 monitors the data read-out status in 1-field units. If the data cannot be supplied in time, the reading of the image data from the disc in units of one field is stopped, and the data of the previous image is held by the control signal to the data reproducing device 4. On the other hand, the audio data is continuously read.

In the simultaneous recording / reproducing state, the system switches the writing / reading processing in field units. That is, writing and reading are time-divisionally processed in field units for each of the image data to be written / read. The three methods for simultaneous recording and reproduction are shown below.

In the first method, the simultaneous recording / reproducing pattern is changed according to the maximum transfer rates of writing and reading that are measured in advance. That is, the two rates are compared, and if the transfer rate at the time of reading is within 1.5 times the average transfer rate at the time of writing, as shown in FIG. It shall be performed every 4 fields. On the other hand, when the transfer rate at the time of reading is 1.5 times or more the average transfer rate at the time of writing, as shown in FIG. To read and play.

In the second method, as shown in FIG. 6, writing and reading are alternately repeated every other field.

Data is thinned out in the above two methods. However, if the write / read rate of data at consecutive addresses is more than twice the average supply data rate, a buffer memory is placed in the middle of the disk to temporarily store data for two fields, Simultaneous recording and reproduction can be performed without thinning out. A third method realizing this is shown in FIG.

In the steady state described above, the system shifts to the system stop state by an external power-off operation. At this time, the value of the average transfer rate of recording and reproduction and other management data are recorded in a predetermined area of the disk of the data storage device 3, and then the stop state is entered.

In the above description, the data supplied from the data supply device 1 is the data compressed by the JPEG method.
The present invention can be applied to any system in which 1 is adaptively controllable.
PEG (Moving Picture Expert)
s Group) data may be compressed.

In the above description, the video data and the audio data are stored in the data storage device, but it is also possible to store additional data such as character data.

[0039]

As described in detail above, according to the present invention, it is possible to perform optimum real-time access processing for each storage medium when the storage medium is replaced. Further, by recording the test result in a predetermined area of the storage medium, it is not necessary to carry out the test each time the power is turned on, so that the number of tests can be reduced. Furthermore, the test method can be changed without depending on the storage medium. The above effects are particularly remarkable when a storage medium having a large variation in data access capability depending on the model such as a hard disk drive and the area of the disk is used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a data storage system to which the present invention is applied.

FIG. 2 is a diagram showing an operation after the system is powered on.

FIG. 3 is a diagram showing a method for testing write / read capability.

FIG. 4 is a diagram showing a simultaneous recording / reproducing system in which writing and reading are performed every four fields.

FIG. 5 is a diagram showing a simultaneous recording / reproducing method in which continuous 2 fields are read out every 4 fields with respect to writing every 4 fields.

FIG. 6 is a diagram showing a simultaneous recording / reproducing method in which writing and reading are alternately repeated every other field.

FIG. 7 is a diagram showing a simultaneous recording / reproducing method without thinning out data.

[Explanation of symbols]

1 ... Data supply device, 2 ... Control block, 3 ...
Data storage device, 4 ... Data playback device

Claims (8)

(57) [Claims] 1. A data storage device having a replaceable storage medium built-in, and a control block, wherein the control block writes / writes the storage medium.
A storage device for real-time data, characterized by having a means for evaluating read capability and having a maximum transfer rate per unit time for a continuous area of a storage medium as a write / read capability. 2. A data storage device having a storage medium configured to be replaceable therein, and a control block, wherein the control block writes / writes the storage medium.
A real-time data storage device characterized by having a means for evaluating read-out capability, evaluating write-ability and read-out capability, and taking the lesser one as the evaluation value, and performing writing / reading based on the evaluation value. 3. A data supply device in which the amount of data generated per unit time is variable under the control of a control block, and the upper limit value of the amount of data generated per unit time does not exceed an evaluation value. The real-time data storage device according to claim 2. 4. The real-time data storage device according to claim 3, wherein when the upper limit value of the data generation amount per unit time exceeds the evaluation value, the writing of data is temporarily stopped. 5. A write / read capability of a replaceable storage medium built in a data storage device is evaluated, and a maximum transfer rate per unit time for a continuous area of the storage medium is set as the write / read capability. A method for writing / reading real-time data, which is characterized in that 6. A method of evaluating writing and reading capabilities of a replaceable storage medium built in a data storage device, wherein a smaller one is used as an evaluation value, and writing / reading is performed based on the evaluation value. Characteristic real-time data write / read method. 7. The method according to claim 6, wherein an upper limit value of the data generation amount per unit time of the data supply device having a variable data generation amount per unit time does not exceed an evaluation value. Real-time data write / read method. 8. The method for writing / reading real-time data according to claim 7, wherein when the upper limit of the amount of data generated per unit time exceeds the evaluation value, the writing of data is temporarily stopped. .