JPH02122488A - Cd-rom disk reproducing device - Google Patents

Abstract

PURPOSE:To improve apparent access speed by executing the area data reading necessary for disk reproduction beforehand at the time of disk loading. CONSTITUTION:When a disk 306 is loaded, a pickup 305 is moved to a prescribed address part on the disk 306 by an access means, data in the address part are read, and the data are controlled so as to be stored nto a memory means 320. When the reading instruction of the stored data is issued from a host system 322, the data stored in the memory means 320 are transferred. Thus, the apparent access speed can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a CD (optical compact disc) type disc playback device, and particularly to a CD-ROM disc playback device.

(Prior art) A CD-based disc playback device plays a disc at CLV (
The disk is rotated using a constant linear velocity (constant linear velocity) method, and the disk is reproduced using a linear tracking method from the inner circumference side to the outer circumference side of the disk using an optical pickup incorporating a semiconductor laser and a photoelectric exchange element. The above-mentioned disk is a transparent resin disk having a diameter of 12 mm and coated with a metal thin film that forms pits (irregularities with different reflectances) corresponding to digital PCM data. Therefore, digital recording and playback is performed, and compared to conventional analog recording and playback systems, high-density recording (about 1 hour in stereo) and advanced control functions and performance are realized.

The above-mentioned disk contains subcode data for improving operability and realizing advanced functions, as well as a reproduced music signal for stereo reproduction. The subcode data consists of 8 bits per frame (subcode P to subcode W), of which subcode P (1 bit) is data indicating the change in the six songs recorded on the disc. . The subcode R-W (G bit) is data for displaying an image on, for example, a TV screen in synchronization with the reproduced music signal. Subcode R
By playing back a disc on which -W is recorded and connecting a dedicated decoder, it is possible to display a still image on the TV screen with almost the same resolution as an MSX personal computer. Subcode Q (1 bit) is called address data and is located in the program area (25 radius on the disk).
In the area (~2g++s), the song numbers (TNO), clause numbers (INDEX), elapsed time (TIME), and total elapsed time (ATIME) from the program area start position are shown for the six recorded songs. In addition, the lead-in area (radius 2
3 to 25 m+s), there is a TOC (Table of
Contents) data is recorded. Since the amount of information recorded on a disc is enormous, disc playback devices are equipped with a search function to easily and selectively play back the desired data to be played back. For execution, subcode Q is used.

The CD system is a system aimed at reproducing music, but focusing on its enormous recording capacity, the CD-ROM (Compact
A Disc-Read 0nly Men+ory) method was developed. In this method, digital information is recorded and reproduced by adding a new format to the previously described CD recording and reproduction format for music reproduction without changing it. The CD system uses two channels of analog signals at 44.1. KIIz is sampled and recorded as a 16-bit digital PCM signal, but C
In the D-ROM system, as shown in FIG. 3, these 16 bits are divided into 8 bits (1 byte) each, and data is recorded in 2352 bytes as one unit (1 block). However, the structure of the data shown in the figure is as follows.

■Synchronization pattern (1
2 bytes) ■Address information of the block corresponding to subcode Q (1
775 seconds (4 bytes) ■Data used by the user (2048 bytes - 2 bytes) ■Data for data error detection and error correction (MODE 1) (288 bytes) or data used by the user (MODE 1) 2) (288 bytes) When the data of ■ above (MODE L) is selected, the CD for music playback
It is used when errors cannot be corrected by C1 and C2 parity correction in the format, and the error rate is ultimately 10.
CI has been improved to the point where CI is used as a computer recording medium.
) - it becomes possible to use ROM. Furthermore, a mode (MODE 2) is defined in which this data is used as data that can be used by the user. In this mode,
The data error rate is 10-9, but the data that can be used by the user per block is 2048 + 288-2338.
It has even increased to a part-time job.

Note that the above 1 block is 1 of the subcodes mentioned above.
This corresponds to one frame, and l blocks are played every l/75 seconds. For example, MODE L data is 2 bytes/block, so the CD-ROM data transfer rate is 2KX 75-150 bytes per block.

Therefore, a CD-ROM disc recorded on one side for 1 hour has 150Kx 60x GO-540yl
It is possible to record gigabytes of information. This recording capacity is equivalent to 500 to 1°OO ordinary floppy disks, or about 270,000 documents with 2000 characters per page. In other words, the CD-ROM system can be said to be a data recording medium with a low error rate and a large storage capacity. Furthermore, instead of using the entire CDROM disk as a data recording medium, a portion can be used as a conventional music signal recording area. That is, by rewriting the control bits of the subcode Q according to the data area/music signal recording area, data and music can be mixed for each song.

Since a CD-ROM disc is simply an information recording medium, there is a host system (host computer) that processes this information.

That is, by operating the keyboard of the host computer, a predetermined command is transferred from the host computer to the CD-ROM disc playback device, and the CD-ROM disc is played back.
Search for a desired address in the M disc playback device. After the search is completed, the user data at the requested address is transferred from the CD-ROM disc playback device to the host computer, and the data processing is executed by the host computer. As described above, the CD-ROM system operates according to the above-described procedure.

The data transfer speed of the host computer connected to the CD-ROM disk playback device varies depending on the performance of its CPU, the application software that operates the CD-ROM disk playback device, etc., and the data transfer speed of the CD-ROM disk playback device Speed (150KBytes
/See), a buffer memory for data transfer is provided in the CD-ROM disc playback device.

Normal data read processing is executed in the following steps.

(2) A command (Read command) specifying the target address and transfer data length is issued from the host computer to the CD-ROM disk reproducing device.

(2) CD-ROM CDROM disk The pickup is moved based on the address data read from the disk (access operation).

■Repeat the above procedure until the target address is reached, and then write the user data read from the disk to the buffer ram.

(2) After writing to the buffer ram is completed, the CD-ROM disk reproducing device generates a read request signal to the host computer.

(2) The host computer receives the requested data from the CD-ROM disc playback device based on the interface rules, and the data reading process is completed.

(Problems to be Solved by the Invention) As described above, since the CD-ROM disc playback device is used as a data recording device for a computer, it is required to have a high data reading speed. However, in conventional CD-ROM disc playback devices, after a command is issued from a host computer,
To initiate the access operation to move the pickup,
There is a problem that the data read speed decreases.

The present invention is intended to solve the above-mentioned conventional problems,
It is an object of the present invention to provide a CD-ROM disc reproducing device that can instantly transmit desired data to a host computer when a specific command is issued from the host computer.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a pickup for reading data from a disk, a storage means for storing predetermined data read from the disk by the pickup, and a predetermined data read from a host system. access means for moving the pickup to a target address in response to a data read command; and when the disk is loaded, the access means moves the pickup to a predetermined address portion on the disk in advance, control to read data and store this data in the storage means; and control to transfer the data stored in the storage means when a command to read the stored data is issued from the host system. It is equipped with a control means to

(Function) In the present invention, when loading a disc, data in an area necessary for disc playback is read out and stored in advance, and when a command to read the stored data is issued, the stored data is read out and stored in advance. to the host system. Therefore, the apparent access speed can be significantly improved.

(Example) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram for explaining the configuration of a CD-ROM disk reproducing apparatus according to an embodiment of the present invention.

As shown in the figure, in the CD-ROM disk playback device of this embodiment, a disk motor 303 and a pickup feed motor 304 are driven from a control circuit 301 via a disk playback system control circuit 302, and a pickup 30 is driven.
When the laser diode 5 is turned on, the disk 30
6 is reproduced by the pickup 305, and the reproduced signal is sent to the RF detection circuit 307.

This RF detection circuit 307 amplifies the supplied signal,
The reproduced EFM signal is separated into a signal supplied to the servo circuit 308 and a signal supplied to the EFM demodulation circuit 309.

Here, the servo circuit 308 controls the pickup 305 with focus servo and tracking servo, controls the pickup feed motor 304 with linear tracking servo, and controls the pickup feed motor 304 with linear tracking servo.
Various signals for performing CLV servo are sent to 03. Note that various servos are performed based on these various control signals and control signals sent from the control circuit 301 via the disk reproduction system control circuit 302.

The EFM demodulation circuit 309 shapes the waveform of the reproduced EFM signal, performs EFM demodulation, separates a synchronization signal that becomes subcode data, supplies this synchronization signal to the subcode Q detection circuit 310, and detects that the synchronization signal is The separated reproduction signal is supplied to a D/A conversion circuit 311, an unscrambler 312, and a synchronization detection circuit 313.

Here, the subcode Q (address data) detected by the subcode Q detection circuit 310 is T in the lead-in area.
If it is OC data, it is taken into the program RAM 314 via the control circuit 302 and used to realize a high-speed search operation.

In addition, the reproduced signal converted back to an analog signal by the D/A conversion circuit 311 is supplied to the speaker drive circuit 315 after necessary error correction and error correction processing is performed, thereby driving the speaker to play. be done.

The reproduced signal (data shown in FIG. 3) sent out from the EFM demodulation circuit 309 is sent to a synchronization detection circuit 313 that detects the block synchronization pattern of the CD-ROM disc and an unscrambling circuit that descrambles the signal based on predetermined rules. The data for one block shown in FIG. 3 is supplied to the scrambler 312 and taken into the decode RAM 31B.

In addition, only the header data (corresponding to the address data of subcode Q) in the block ■ is detected by the header detection circuit 31.
7 and is supplied to the control circuit 301. When searching for desired data, the control circuit 301 uses the subcode address supplied from the above-mentioned subcode Q detection circuit 310 and the C supplied from the header detection circuit 317.
A search operation is performed using the address of the D-ROM data. According to the standard, this is the subcode low address and CD-R
This is because the OM header addresses are allowed to differ by a maximum of one second, so the final search operation is always performed using the CD-ROM header address. Decoder RAM 3
The data written to 1B is subjected to a predetermined error detection process, and if an error has occurred, the data is sent to the control circuit 301.
performs error correction using decoder RAM controller 318 and error correction circuit 319.

The data in the decoder RAM 3113 for which error correction has been completed is taken into the buffer RAM 320. however,
All data in the decoder RAM 31G is not transferred, but the control circuit 301 is transferred to the RAM controller 3.
18 is used to transfer only the user data shown in FIG. 3 to the buffer RAM 320.

After all desired data is written into the buffer RAM 320, the control circuit 301 supplies a data read request signal to the host computer 322 via the host computer interface 321.

After the host computer 322 is ready to read the data, the host computer interface 32
1 to the control circuit 301, and after receiving this signal, the control circuit 301 controls the address of the user data in the buffer RAM 320 using the RAM controller 323, and sends the data to the host computer 322. Transfer.

Normally, this system is controlled by selectively operating the keyboard of the host computer 322, supplying a predetermined command to the control circuit 301 via the host computer interface 821, and controlling the disc playback system to a predetermined state. is in operation, but a key switch group 324 is provided so that simple operations can be performed even when the host computer 322 is not connected.

Further, as described above, the necessary display is normally made on the CRT of the host computer 322, but in consideration of the case where the host computer 322 is not connected, a simple display is displayed via the display power control circuit 325. The configuration is made on the portion 32B.

In addition, the program RAM 314 and the program ROM
327 stores a predetermined program for driving the control circuit 301.

By the way, the data structure (synchronization pattern, header address, user data, error correction code structure) of the CD-ROM disk mentioned above is specified in the CD-ROM standard, and is usually converted into a physical format (
All CDs called Physical Format
- The ROM disk (media) is recorded according to this format, but the content to be recorded in the user data therein is of course a standard that the user can freely decide.

The structure of the user data (for physical format,
One of the standards that defines a logical format (called a "Logical Foriat") has been announced.

This standard is for FDD (floppy disk drive)
and HDD C hard disk drives) as well as CD-
This is a standard for handling ROM disk playback devices.

This logical format is generally
For example, the main structure (Tree 5 structure) of the otretory or the old
The structure of % PathTable corresponds to High Sierra PortaL.

As one of the standards of Hi-Sierra ForIlal, V T OC (Volume or Table
of'Contents). This is: ■Root old directory address information.

■Path Table address information.

■This is the area where copyrsight information 0, etc. is recorded, and the basic information necessary to handle CD-ROM discs is recorded (according to the standard, the signal is 0 minutes 2 seconds 18 frames on the disc). ). Therefore, the host computer must read this area first, and then execute R according to that information.
Read OOT Directory and then SυB
Processing such as reading the Directory is being executed. In this system, after a CD-ROM disc as a medium is loaded into a CD-ROM disc playback device, the host computer always issues the above-mentioned VTOC data read command. Therefore, CD
- In a ROM disc playback device, when a CD-ROM disc is loaded, it can be expected that the first command from the host computer will be "read data of 0 minute 2 seconds IB frame".

Next, the data reading operation of the CD-ROM disk reproducing apparatus configured as described above will be explained using the flowchart shown in FIG.

First, the control circuit 30 is sent from the host computer 322 via the host computer interface 321.
1, a disk load command is issued. Or CD-
By operating a key switch group 324 provided in the ROM disk playback device, the disk load is controlled by the control circuit 30.
1 (step 1).

After this, the CD-ROM disc playback device operates the disc caddy or closes the disc tray, and then puts the servo circuit 308 into an operating state via the disc playback system control circuit 302, and then controls the focus servo and tracking servo. is turned on. Further, the control circuit 301 reads subcode lower address data read from the disk 306 via the subcode Q detection circuit 310, reads TOC (Table or Contents) data necessary for subsequent operations, and stores the data in the program RAM 314. (Step 2).

After the above-mentioned initialization procedure is completed,
The control circuit 301 drives the pickup feed motor 304 to move the pickup 305 to the area where the VTOC data is recorded, that is, to the front of 0 minute 2 seconds 16 frames (access operation) (step 3).

Thereafter, the drive of the pickup feed motor 304 is stopped and the process waits until predetermined data (data of 0 minute 2 seconds 1B frame) is reproduced from the disk 30B.

After this, the reproduced data is transmitted to the RF detection circuit 307, E
Necessary demodulation processing is performed in the FM demodulation circuit 309, and the CD-
Unscrambler 31 compatible with ROM format
2 and the synchronization detection circuit 313. The data is then separated into Herada data and user data/error correction code parts, and the user data/error correction code is decoded by the RAM controller 318.
It is temporarily written to A M 31G. Additionally, if there is an error in the written data, the control circuit 301
By driving the error correction circuit 319, necessary error correction is performed. After the error correction is completed, the control circuit 301 controls the RAM controller 318 and the RA F
Decode RAM 3 using v1 controller 323
The data in 1B is transferred to the buffer RAM 320 (step 4).

After this, when the VTOC data is written to the buffer RAM 320, a series of initialization operations of the CD-ROM disc playback device is completed, and the drive enters a standby state in which it is capable of receiving commands from the host computer (step 5).

The control circuit 301 then checks whether a data read command (Read command) has been issued by the host computer 322 via the host computer interface 321 (step 6).

If the issued data read command is not an access with the target address set to 0 minutes 2 seconds 16 frames indicating VTOC, that is, if it is other than the 0 minutes 2 seconds 16 frame of the target address, then the access operation for the commanded target address is performed. (step 8), reads the data at the target address, and transfers the data to the buffer RAM 320 (step 9).

Also, in step 7, the destination address 0 minutes 2 seconds 16
When a frame data read command is issued, the data previously written in the buffer RAM 320 in step 4 is transferred to the host computer 322 using the RAM controller 323 and host computer interface 321 (step 10).

In other words, if the data read command after disk loading has a target address of 0 minutes 2 seconds 16 frames (normally, the first data read command after loading has a target address of 0 minutes 2 seconds 16 frames). ), there is no need for access that requires pick-up and movement, and the apparent access time is 0.
It can be done.

[Effects of the Invention] As explained above, the CD-ROM disc playback device of the present invention reads data from an area necessary for disc playback in advance when loading a disc, thereby allowing a specific command to be issued. If, instantly,
Immediately transfer the desired data to the host system. Therefore, the apparent access speed can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the configuration of a CD-ROM disc playback device according to an embodiment of the present invention, and FIG.
A flowchart for explaining the data read operation in the CD-ROM disc playback device shown in FIG.
- It is a figure for demonstrating the structure of the data of ROM system. 301... Control circuit, 302... Disc playback system control circuit, 304... Pickup feed motor, 305
...Pickup, 307...RF detection circuit, 30
9... EFM demodulation circuit, 310... Subcode Q detection circuit, 312... Unscrambler, 314...
・Program RAM, 31G...Decode RAM,
318.322...RAM controller, 320.
...Buffer RAM, 321...Host computer interface, 322...Host computer, 327...Program RAM0 Applicant
Toshiba Corporation

Claims (1)

[Scope of Claims] A pickup for reading data from a disk, a storage means for storing predetermined data read from the disk by the pickup, and moving the pickup to a target address in response to a predetermined data read command from a host system. an access means for causing the pickup to be moved to a predetermined address portion on the disk by the access means in advance when the disk is loaded, reading data at this address portion, and storing this data in the storage means. It is characterized by comprising a control means for controlling the storage means and for controlling the data stored in the storage means to be transferred when an instruction to read the stored data is issued from the host system. CD-ROM disc playback device.