JPH07141658A - Cd-rom device - Google Patents

Abstract

PURPOSE:To transmit an error rate to a main machine after final processing by providing a work area in a CD internal buffer RAM, counting the number of errors for every generation of error by error codes and totalling them in a ROM device. CONSTITUTION:The host machine issues an error count page of a mode selection command after initializing. A CPU for CD receives it by an SCSI controller, and initializes an error counting area in the internal buffer RAM. The CPU issues a read/write command and commands the read of a specified section. The CPU actuates a CD-ROM device, and processes reading information. When the error generates at this time, the CPU adds +1 to respective error count values in the RAM. When the read of the specified section is ended, the host machine reads the value of the error count page of the mode selection command. The CPU for CD receives the command by the SCSI controller, and transmits the value of the error counting area to an SCSI bus. The main machine displays respective error count values on a video to inform a user. When an error incapable of restoration generates, the processing is immediately ended, and shifted to the display of the error rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CD-ROM device used in a game machine or a computer using a CD.

[0002]

2. Description of the Related Art An optical compact disc (CD) was developed as a medium capable of digitally recording and reproducing voice, and has become popular as a CD audio disc capable of reproducing faithful sound and continuously reproducing for a long time. Furthermore, attention is paid to large capacity and high-speed access performance, and its use as a recording medium is advancing.

The data structure of a CD audio disc will be described. L / R audio signal is PCM modulated and 1
Obtain digital data of 6 bits × 2 channels. 24 bytes of digital data in 6 sample sections are in 1 frame units. For the purpose of suppressing errors, when data is converted in units of L / R 12 bytes, an error correction code is entered and interleaved, 8 bits × 12 data and 8 bits × 4 parity are respectively obtained. A 1-byte subcode is added to 1 frame, and a digital signal obtained by modulation is recorded on a CD.

98 frames form one subcode block. The first 2 bytes are the subcode header,
The remaining 96 bytes are the subcode 8 channels. Of the subcode, 24 bytes are used for read control,
Address information for searching, such as the type of user data, absolute time, and subcode frame number, is recorded. 1
The data attached to one subcode block is 2352.
Equivalent to the amount of information in bytes.

The CD audio disc reproducing apparatus is provided with a program function using sub-codes, such as a cue of a music piece and setting of a reproduction order, as means for performing digital signal processing. Using the index on the innermost circumference of the disc as a clue,
The sub-code is searched for and demodulated, and the target block is searched by the absolute time of the sub-code. The read digital signal is demodulated, error correction is performed by deinterleaving and error correction code, and digital signal processing is performed to obtain digital data. Digital data is processed by D / A converter,
It is output as an audio signal.

A typical example of using an optical compact disc as a computer recording medium is a CD-ROM whose physical format is a unified standard. CD-R
The OM physical format standard is shown in FIG. As the physical format, three kinds of modes of mode 0, mode 1 and mode 2 are defined. One sector of CD-ROM is
It is composed of data of 2352 bytes which is equal to a subcode block of a CD audio disc, and a 12-byte block sync signal (sync) is placed at the head of each block for separating the blocks.

After the block synchronization signal, 4 bytes of header are arranged, which consists of 3 bytes of block address and 1 byte indicating the data recording mode. In mode 0 and mode 2, the remaining 2336 bytes become the data area. In mode 0, this data is all 0s.

Mode 1 is used for computer data that requires more accurate error correction. Program data, image data having a high compression rate, and the like cannot operate normally even with a 1-bit error. Unlike such image data or acoustic data that can be interpolated, such data is not allowed to have errors.

In order to improve the reliability of the data of the CD-ROM, an auxiliary data area is set in the data structure of 2336 bytes, and 2048 bytes of user data and 28
Divided into 8 bytes. The setting of auxiliary data is defined by setting the data recording mode to mode 1. 288 bytes of auxiliary data are 4 bytes for error detection,
The error correction is 276 bytes including 8 bytes of space, 172 bytes of P parity and 104 bytes of Q parity.

Mode 2 has a data structure in which 2336 bytes are all user data, and image / sound data and the like that can be error-corrected by interpolation processing can be recorded. However, in general, define the structure in the user data of mode 2,
The physical format is expanded and the data structure of mode 2 is used when performing time division processing of various data. The program data and the like have a large number of consecutive redundant codes having the same code, and read errors are likely to occur. Therefore, in the block of 2352 bytes in which the sync data, the header data, and the auxiliary data data are added to the user data, the scrambling process is performed while leaving the sync data to eliminate the redundant code.

After the scramble process, like the CD audio disc, an error correction code is inserted and interleaved, a subcode is added, and a modulated digital signal is recorded in a CD-ROM.

The subcode corresponds to the structure of the CD audio disc, and one subchannel having a size of 8 channels × 12 bytes is added to one block. Of these, two channels are used for read control, and address information for searching, such as the type of user data, absolute time, and subcode frame number, is recorded.

The CD-ROM reproducing device is a computer,
An image display means such as a CRT or a printer, a data input means such as a keyboard, and a CD-ROM reading means are combined. In response to the address designation by the computer, the CD-ROM reading means performs digital signal processing in exactly the same manner as the reproduction of a CD audio disc.

Since the obtained digital data is scrambled, the sync in the data block is detected to descramble it, the header address is detected, and then the target block is accessed. After the error detection and correction using the auxiliary data is performed according to the data structure mode in the header, the user data is read into the computer. The reliability of data is enhanced by such a two-step error correction function.

The CD-ROM is common with the CD audio disc in digital signal processing. Originally CD-
Since the ROM is derived from the CD audio disc, most CD-ROM reading means are
It also serves as a playback device for audio discs.

The CD-ROM reproducing device is utilized as a multimedia, and image data as well as program data,
We handle acoustic data. The data transfer rate of the CD-ROM reading means is based on 1/75 second per block. By matching the data transfer rate to that of a CD audio disk and setting 1/75 second as a reference, it is used as a shared machine.

As the image display means such as a CRT, the NTSC system in which the horizontal synchronization and the vertical synchronization are about 16 kHz and about 60 Hz, respectively, is widely used. When displaying a moving image using a multimedia composed of a CD-ROM and a computer, the CPU prepares each screen data by processing the image data in the vertical blanking period every 1/60 seconds. Since the CD-ROM reading means transfers data every 1/75 second, the image data is temporarily held in a dedicated secondary buffer and is read from the buffer at a rate equal to the vertical synchronizing signal to achieve synchronization. ing.

In both the CD audio disc and the CD-ROM, the subcode has a space of 6 channels × 12 bytes. By inserting character data or image data here, a screen display function is added or supplemented. Even a CD audio disc can be displayed on the screen by providing a circuit for converting data into characters and images, a CRT, etc. in the reproducing device.

[0019]

In the conventional CD-ROM device, an error is displayed when a serious error occurs and the CD data cannot be used. However, there was no indication or warning about errors that could be repaired even if an error occurred, such as slow processing speed. For this,
There were times when I continued to use the CD in question without knowing the cause.

It is an object of the present invention to provide a device capable of finely tabulating CD errors, analyzing the results as an error occurrence rate, and notifying the user.

[0021]

The CD-ROM device of the present invention collects CD errors in the CD-ROM device and notifies the host machine as an error rate at the end of processing.
For this reason, a work area is provided in the CD internal buffer RAM, and an error count is taken for each error code each time an error occurs.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a CD including a CD-ROM shown in FIG.
The procedure until the error rate is displayed on the host machine will be described using the ROM device as an example.

1. The host machine is MODE SELECT
After initializing the error count page of the T command,
Issue.

2. The CD CPU sends the command to the SCS
Received by the I controller, the work area for error count in the CD internal buffer RAM is initialized.

3. Next, the host machine issues a PLAY command or a READ command to instruct reading of the designated section.

4. The CPU for CD receives the command by the SCSI controller, operates the CD-ROM drive device,
Then, the read data is processed.

5. If an error such as C1 or C2 occurs during this period, the CD internal buffer RAM (work area)
Each error count value in is incremented by one.

6. After reading the specified section, the host machine reads the value of the error count page of the MODE SENSE command.

7. The CPU for CD receives the command by the SCSI controller and sends the value of the work area for error counting to the SCSI bus through the SCSI controller.

8. The host machine displays each error count value on the video display and informs the user using this device as the number of error occurrences of the CD-ROM device.

The flow chart of FIG. 3 simply shows the above procedure. Generally, when an unrecoverable error occurs in error recovery, the process immediately ends and moves to the error occurrence rate display process. However, depending on the processing, even if an unrecoverable error occurs, the processing may be continued, so that determination is omitted in the figure.

[0032]

By using the device according to the invention, the user is informed of the details of the error, whereby the subsequent C
Information that can improve D and CD data can be obtained. In particular, although no information has been obtained so far about the data which has been repaired even if an error has occurred, the present invention has the effect of making it possible to understand in detail and to easily understand the problem.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a data format structure of a CD-ROM.

FIG. 2 is a relationship diagram between a CD-ROM device and a host machine in the device of the present invention.

FIG. 3 is a flowchart showing an error occurrence rate display by the CD-ROM device of the present invention.

Claims (1)

[Claims] 1. A CD-ROM device comprising a work area provided in a CD internal buffer RAM and means for counting each occurrence of an error.