JPH0778102A - Artificial cd-rom device - Google Patents

Abstract

PURPOSE:To make it unnecessary to prepare a virtual CD-ROM disk and to reduce turn-around time by providing this artificial CD-ROM device with a correlation table and a means for converting a data format from a management and control device format to a CD-ROM format at real time. CONSTITUTION:A management and control device 10 receives a data transfer instruction obtained from a host computer 2 using a CD-ROM device through an interface circuit 4 having the same interface as the CD-ROM device. The data transfer instruction specifies data to be transferred based upon an address stored in a CD-ROM disk. The device 10 retrieves the correlation table 3 based upon the address and specifies a file in a file management system 11 of a corresponding electronic calculator. The device 10 converts data into CD-ROM format data by a conversion means 6 and transfers the converted data to the host computer 2 through the circuit 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for simulating a data transfer operation of a CD-ROM drive device using a storage device, an interface circuit, the storage device, and a management control device for managing and controlling the interface circuit. Is.

[0002]

2. Description of the Related Art Conventionally, a virtual disk, which is a file in which material data is rearranged in the same data arrangement as a CD-ROM disk, is created on an external storage device, and a CD-R is created.
By converting the address of the OM into a byte position in the virtual disk file and accessing the data, the data transfer operation that is apparently the same as that of the CD-ROM device was simulated.

As another method for enabling data transfer between different file systems, there is a method as disclosed in JP-A-63-59639.

[0004]

Conventionally, a virtual disk must first be created in an external storage device, etc.
The turnaround was getting longer.

[0005]

An external storage device is provided with a correlation table indicating an identifier of a file based on the file management system of the management control device and at which address on the CD-ROM the file is located. Means is provided for converting the data format from the management controller format to the CD-ROM format in real time.

[0006]

The management control device receives a data transfer command obtained from the host computer using the CD-ROM device through the interface circuit having the same interface as the CD-ROM device. The data transfer command is CD-RO
The address on the M disk specifies the data to be transferred. The management control device searches the correlation table based on the address, and specifies the corresponding file under the file management system of the electronic small-sized computer. The management control device converts the file into data in the CD-ROM format by the data conversion means, and transfers the data to the host computer through the interface circuit.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall construction of an embodiment of a pseudo CD-ROM device 1 according to the present invention. In FIG. 1, the management control device 10 is connected to the CD-ROM interface circuit 21 of the host computer 2 via the interface circuit 4. The interface circuit 4 is a CD-R to be simulated with respect to the host computer 2.
The host computer 2 has the same electrical specifications and timing specifications as the OM drive, and the host computer 2 has the same CD-ROM interface circuit 21 as when the CD-ROM drive is used.
Then, the control software sends a data transfer command to the pseudo CD-ROM device 1.

When specifying the data on the CD-ROM drive, the address where the corresponding data is stored is often designated. The format includes physical addressing in units of minutes, seconds, and data blocks, and logical addressing in which a user area head is set to 0 and an ascending sequential number is assigned to each data block.

The management control device 10 receives data designation in these formats. The management control device 10 uses the correlation table 3
CD-ROM by file name search process 12 using
The identifier of the file stored in the storage device 5 is searched from the above address information.

An example of the correlation table 3 is shown in FIG. The correlation table 3 is composed of address information corresponding to the file identifier. That is, when the data of the address 32 (00 minutes 02 seconds 30 data block) on the CD-ROM disc is requested, the file identifier A31 is obtained. Note that, for example, when the management control device 10 uses MS-DOS in the file management system, the file identifier is a file name.

Based on the file identifier, the file management system 11 identifies, for example, the file 51 from the storage device 5 and transfers it to the interface circuit 4. The interface circuit 4 is provided with a data format conversion circuit 6 for converting the data format of the material data 72 to the data format of the CD-ROM data 71.

FIG. 3 shows an example of the CD-ROM data 71 and the material data 72. The material data 72 is a group of continuous data, whereas the CD-ROM data 71 is
SYNC 711, header 712, subheader 713, error control code 714, etc. are added to partial data 710 obtained by dividing the material data 72 into 2048 bytes. When the CD-ROM interface circuit 21 of the host computer 2 receives the data in such a format, it is necessary to convert the format of the data in real time when transferring the file.

FIG. 4 shows a CD-RO to be simulated.
An example of the data format conversion circuit 6 for performing data format conversion in real time so that the data transfer time is equivalent to that of the M device is shown. In this example, an example is shown in which data transfer is performed at a speed four times faster than the encoder used in the data format conversion circuit.

The data format conversion circuit 6 uses the material data 72.
A buffer circuit 61 for receiving the data, encoder circuits 600, 610, 620, 630 for converting the data format, and a multiplexer circuit 62 for selectively outputting the output from each encoder circuit.

Each encoder circuit has the same circuit configuration.
The encoder circuit 600 includes an input FIFO 601, an encoder 602, and an output FIFO 603. Input F
The IFO 601 stores the data transferred by the buffer circuit 61, and transfers the data in the order of storage in synchronization with the data input of the encoder 602. In addition, the buffer circuit 61
The half full signal 604 is generated when the data received from the device exceeds 1/2 of the capacity. The encoder 602 is
The data is received from the input FIFO 601 and the data format is converted to the CD-ROM format and written in the output FIFO 603. The output FIFO 603 is the input FIFO 601.
Similarly, the received data is stored and the data is output in synchronization with the reading of the multiplexer circuit 62.

The input FIFO 601 has a capacity of 2048 bytes, which is 2/3 or more of the size (2352 bytes) of one data block of a CD. File management 11
Transfers the material data 72 to the buffer circuit 61. The buffer circuit 72 distributes the data of one data block to the respective encoder circuits 600, 610, 620, 630.

The data transfer procedure will be described with reference to FIG. The buffer circuit 72 first transfers 1/3 of the data of the first data block to the encoder circuit 600 (first transfer). Next, 1/3 of the data of the second data block is transferred to the encoder circuit 610 (second transfer).
Similarly, ⅓ of the third data block is transferred to the encoder circuit 620 (third transfer), and the fourth is transferred to the encoder circuit 630.
1/3 of the above data block is transferred (fourth transfer).
Here, since the input FIFO 601 has not yet reached 1/2, the half-full signal 604 has not been output. Therefore, another 1/3 of the data is transferred (fifth transfer).
Similarly, the encoder circuit 620 and the encoder circuit 63
0, data is transferred to the encoder circuit 640. In this state, if each encoder has not finished processing the data of the input FIFO 601, each half-full signal 6
Since 04 is output, the data transfer is stopped. Later,
1/3 when half-full signal 604 is not output
Transfer data block by block. By this operation, the data can be continuously supplied without causing the input FIFO 601 to overflow. The data processed by each encoder is stored in the output FIFO 603. The multiplexer 62 fetches data from the output FIFO 603 of each encoder circuit in order of the encoder circuit 600, the encoder circuit 610, the encoder circuit 620, and the encoder circuit 630 at a speed four times the processing speed of each encoder, and outputs the data.

The operation when the file corresponding to the designated address does not exist due to the arrangement of the material files on the CD-ROM disc will be described with reference to FIG.
Depending on the allocation of the material file 51 and the material file 52 on the CD-ROM disk 53, there may be a free area 54 in which no file exists. In this case, the management control device 10 uses the correlation table 3 and the material file 51,
When the empty area 54 in which no file exists is detected from the size of the material file 52 and the data transfer of the area is designated by the host computer 2, only the address information part is stored as the assumed address information and the other part is stored. Transfers data that is 0.

[0020]

According to the present invention, since it is possible to access a file under the file management system of the management controller by addressing on the CD-ROM disk by using the correlation table, it is necessary to generate a virtual CD-ROM disk. No, it has the effect of reducing the turnaround time.

According to the present invention, a virtual CD-ROM is used by using a data conversion circuit capable of converting real-time data.
Since a response equivalent to the operation of the CD-ROM drive can be made without generating a disc, the turnaround time required for simulation can be shortened.

According to the present invention, in the data conversion circuit, each encoder is provided with an input / output FIFO, and parallel operation can be performed by supplying data to each encoder without excess or deficiency. Real-time simulation of transfer is possible, which has the effect of improving convenience.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall view of a pseudo CD-ROM device according to the present invention.

FIG. 2 is an explanatory diagram showing a specific example of a correlation diagram used in the pseudo CD-ROM device of the present invention.

FIG. 3 is an explanatory diagram showing a specific example of a data format used in the pseudo CD-ROM device of the present invention.

FIG. 4 is a block diagram showing a specific example of a data format conversion circuit used in the pseudo CD-ROM device of the present invention.

FIG. 5 is an explanatory diagram for explaining the operation of the present invention.

FIG. 6 is an explanatory diagram for explaining the operation of the present invention.

[Explanation of symbols]

 1: Pseudo CD-ROM device 2: Host computer 3: Correlation table 4: Interface circuit 5: Storage device 6: Data format conversion device 10: Management control device 11: File management system 12: File name search process 21: CD-ROM Interface circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinobu Imada 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Stock AV equipment division, Hitachi, Ltd. (72) Toshihiro Matsunaga 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Hitachi Image Information System Co., Ltd.

Claims (4)

[Claims] 1. A CD using a storage device, an interface circuit equivalent to a CD-ROM device, and a management control device for managing and controlling the storage device and the interface circuit.
A device for simulating a data transfer operation of a ROM device is characterized in that a correlation table of a file identifier based on file management used by the management control device and address format information of a CD-ROM disc is provided on the storage device. Pseudo CD-ROM device. 2. The pseudo CD-ROM device according to claim 1, wherein when data transfer of an area in which a file based on file management used by the management control device does not exist is requested, an address of an address format of a CD-ROM disc is requested. A pseudo CD-ROM device which transfers data which has information but is 0 in the other parts. 3. A device for simulating a data transfer operation of a CD-ROM device using an interface circuit equivalent to a CD-ROM device and a management control device for managing and controlling the storage device and the interface circuit. A CD trying to simulate a file in the file management format used by the management control device on the storage device at the transfer speed.
A pseudo CD-ROM device, characterized in that it is provided with means for converting the data format to the output format of the ROM device in real time. 4. The data format converting means according to claim 3, wherein the number of formatters having a processing speed of 1 / n of the data transfer speed (n is a natural number) and the transfer provided to each input of the formatter. A FIFO memory having a capacity larger than ⅔ of a unit data block, and ½ of the capacity when the storage capacity of the FIFO memory becomes ½ or less.
A pseudo CD-ROM device comprising a control circuit for transferring the following data.