JPH01296465A - Information reproducing device - Google Patents

Abstract

PURPOSE:To obtain the quick access by storing the following block data after the number of blocks for data of a reproducing medium if it is larger than a reference value and transfer block data if it is smaller when the data are transferred from a memory. CONSTITUTION:When the read of data is executed by a host computer, a comparison is made between the number of blocks to be transferred to the computer and the reference value T by a comparing part 6. When the number of the transfer blocks is larger than the reference value T, a buffer memory control part 4 is instructed by an instructing part 5 to hold five blocks of N+4-N+8 in the wake of a transfer completion block N+3. Then, when it is smaller than the reference value T, the control part 4 is instructed by the instructing part 5 to hold five blocks of N-N+4 inclusive of a transfer starting block N. By this method, the access operation to the recording medium can be speeded up.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an information reproducing apparatus that reproduces information from a recording medium such as a CD-ROM.

(Prior Art) In recent years, playback devices that use a compact disc as a recording medium to play back information (hereinafter referred to as a CD system) have become popular.

The CD used in this CD system has pits (irregularities with different reflectances) corresponding to digital data formed on one side of a disc-shaped disc made of transparent resin, and an extremely thin metal film such as aluminum is placed on top of the pits (irregularities with different reflectances). pasted,
Furthermore, a hard protective layer is provided thereon.

With this type of CD system, extremely high-quality sound can be played for more than an hour using light from a small disc (disc) with a diameter of 12 cm, without touching the disc. In addition, in such a CD system, in order to make the disc as small as possible, it is desirable to record at the same density on the inner and outer peripheries over the entire surface of the disc. A method is used in which the position of the built-in pickup is changed. This method uses CLV (Co
Instant Linear Velocity).

Recently, attention has been paid to the enormous recording capacity of the above-mentioned CD system, and CD-ROM has been developed as a read-only data recording medium.
(Read Only l+Iemory) has been developed. In such a CD-ROM, digital information is reproduced by adding a new recording format to the above-mentioned CD without changing the recording format.

By the way, the above-mentioned CD system samples two channels of analog signals at 44.1kHz and records them as 16-bit digital signals, but CD-RO
In the M method, as shown in Figure 3, this 16-bit digital signal is divided into 8 bits (1 byte) each and 235
Data is recorded in units of 2 bytes (1 block).

However, the structure of the data shown in the figure is as follows.

■) Synchronization pattern to recognize the start of each block
...... 12 bytes II) Address information for 1 block... 4 bytes ■) Data used by the user ...... 2048 bytes - 2 bytes ■)
Data for data error detection and error correction (
MODEL) or data used by the user (MODE2
)...... 288 bytes And the data (MODEL) in the above ■ is 0 of the music CD format.
1. It is used when the error in C2 parity check cannot be corrected, and the error rate in this case is ultimately 10-1.
It has improved to below 2.

In addition, in the above data (MODE 2), since the data error rate is 10-9 or less, the data used by the user per block is increased to 2048+288=2336 bytes.

Note that the above 1 block is played back every 1/75 seconds, and for example, the data (MODEL) is 2 bytes/1 block, so CD-1? The data transfer rate of OM is (2 bytes/block) x (75 blocks/sec) -150 bytes/block in 7 seconds. As a result,
A CD-ROM disc with one hour of recording on one side can record information of (150 bytes in 7 seconds) x 60 x 60 seconds - 540 megabytes of information. This storage capacity is equivalent to 500 to 1000 regular floppy disks or approximately 2000 characters per page.
Equivalent to 70,000 pieces. In this way, the CD-ROM is a recording medium with a large storage capacity and a low error rate.

Further, a part of the recording area of the CD-ROM can be used as a conventional music area, and data and music information can also be mixed for each song.

By the way, in order to read data recorded on such a CD-ROM, first a predetermined command is transferred from the host computer to cause the CD-ROM driver to search for a desired block. Next, when the search by the CD-ROM driver is completed, this CD is downloaded via the interface.
- The requested user data is transferred from the ROM driver to the host computer.

At this time, the data transfer speed from the CD-ROM to the host computer varies depending on the host computer's CPU performance and the application software that operates the CD-ROM driver, but generally the data transfer speed of the CD-ROM (150XB/5EC) becomes lower. For this reason, a buffer memory for data transfer is usually provided in the CD-ROM driver in order to synchronize the data transfer speed.

In addition to synchronizing data transfer speeds, such buffer memories are also used to control data in the following manner.

That is, first, when a "data read" operation is executed by the host computer, CD-1? is stored in the buffer memory. The data read from the OM is written until it becomes full, and then, after the buffer memory becomes full, writing is continued.

Thereafter, the data is held in the buffer memory.

At this time, the data area held in the buffer memory is, for example, assuming the buffer memory size is 5 blocks, as shown in FIG. The data held in the block (N+1) to (N+5) are five consecutive blocks from the block (N+1) next to the read block (N).

Subsequently, when the next "read data" operation is performed by the host computer, if the requested data is previously held in the buffer memory, the data is immediately transferred from the buffer memory.

This makes it possible to perform the "data read", that is, the access operation at high speed.

(Problem to be Solved by the Invention) By the way, in the data control using the conventional buffer memory described above, when the buffer memory size is set to 5 blocks and data is read from block (N), the data held in the buffer memory is Block (N+1) ~ (N+
5), it is effective when reading data continuously.

However, when data is read by application software, block (N) may be read again depending on the application software. In this case, there is a wait for another access operation to the CD-ROM, which impedes speeding up of the access operation.

Therefore, in order to speed up data reading when rereading the same block, the following can be considered.

That is, as shown in FIG. 5, after the "data read" operation is executed, if the data area held in the buffer memory is read, for example, 4 blocks worth of data from block (N), the buffer memory In this case, data of five consecutive blocks from the first block (N) read out, that is, data of blocks (N) to (N+4), is held.

As a result, even if "data read" of block (N), which is the same block, is executed again, block (N) is immediately read.
) data can be transferred, so it is effective.

However, if continuous "data reading" is requested, for example, data reading from block (N+4), the number of blocks in the buffer memory will be 5 blocks ()l+1 in the block shown in FIG. ) ~ (N+5)
is maintained, whereas in Fig. 5 the block (N
) to (N+4), so data cannot be transferred immediately from the buffer memory.

Therefore, while the data of block (N+4) in the buffer memory is transferred to the host computer, the CD-RO
The access operation for block M is performed again from block (N+5). As a result, there is a waiting period for access, which hinders speeding up of access operations.

Note that the data transfer speed of the host computer is set to 1, for example.
If byte/see is set to 00, block (N+4)
The access time for one block is approximately 20 m5ec. On the other hand, since the average access time for block (N+5) to the old CD-RO is about 100m5, the host computer is forced to wait 1.00-20-80m5ec after reading block (N+4).

The present invention was made under these circumstances = 9
= An object of the present invention is to provide an information reproducing device that can easily and reliably speed up access operations to an information recording medium.

[Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, the information reproducing device of the present invention has the following features:
A holding means for temporarily holding data read from the information recording medium block by block; a comparing means for comparing the number of blocks of data transferred from the holding means with a reference value; and a comparing means based on the comparison result of the comparing means. For the holding means, if the number of blocks is larger than the reference value, the data from the next block following the last block of the data to be transferred is held, and if the number of blocks is smaller than the reference value, the data of the data to be transferred is held. and an instruction means for instructing to hold the data of the next block following the first block including the first block.

(Function) In the information reproducing apparatus of the present invention, the instructing means tells the holding means, based on the comparison result of the comparing means, that if the number of blocks is larger than a predetermined value, the next block following the last block of data to be transferred is It is possible to instruct to retain the data after the block, and if the number of blocks is smaller than the standard value, to retain the data after the next block following this first block, including the first block of data to be transferred. .

(Example) Hereinafter, details of an example of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of a CD-ROM playback device.

As shown in the figure, the CD-ROM playback device includes a buffer memory 3 that temporarily holds data read by the pickup 2 from the disc in each block, a data holding operation of the buffer memory 3, and a data transfer operation. A buffer memory control unit 4 controls the number of blocks of data transferred from the buffer memory 3, a comparison unit 5 compares the number of blocks of data transferred from the buffer memory 3 with a reference value to be described later, and the buffer memory control unit 4 controls the number of blocks in the buffer memory 3 based on the comparison result of the comparison unit 5. An instruction unit 6 is provided for instructing blocks of data to be held.

Next, the operation of such a CD-ROM reproducing apparatus will be explained using FIG. 2.

Note that the size of the buffer memory 3 described below is assumed to be 5 blocks. Moreover, the reference value T is preferably about 2 to 3 blocks based on experience, and here it is set to 3 blocks. Furthermore, it is assumed that the number of blocks transferred to the host computer is 2 and 4.

Generally, most of the data recorded on the disc 1 is data consisting of image data with a large amount of data and key data for data retrieval with a small amount of data. As a result, it is possible to predict whether the data requested by the host computer is image data or key data for data search by setting the reference value T to, for example, 3 blocks and comparing it with the number of blocks transferred to the host computer. I can do it. Furthermore, in the case of image data, the data is often read out continuously, and in the case of key data for data retrieval, the same block is often read out again, so it is difficult to read the data requested by the host computer. It can be predicted.

First, when a "data read" operation is executed by the host computer, the comparator 5 compares the number of blocks transferred to the host computer with a reference value T.

Then, when the number of transferred blocks is larger than the reference value T, as shown in FIG. Instructs to hold five consecutive blocks of data from (N+4) to (N+8).

After this, 5 blocks are stored in buffer memory 3 (lJ+4
) to (N+8) are held.

As a result, continuous reading from the host computer becomes effective.

Also, the number of blocks transferred to the host computer is the standard value T
If the transfer start block (N) is smaller, the instruction unit 6 instructs the buffer memory driver 4 to transfer five consecutive blocks (N ) to (N+4).

After this, 5 blocks (N) to (
Data up to N+4) are held.

As a result, the same block can be read again by the application software.

As described above, in this embodiment, when the number of blocks transferred to the host computer is larger than the reference value T, the instruction unit 6
is 5 blocks (N+4) to (N+) from the next data block (N+4) following the transfer end block (N+3).
8) can be instructed to retain data up to 8). Further, when the number of transfer blocks is smaller than the reference value T, the instruction unit 6 transfers five blocks (N) to (N+4) including the transfer start block (N) and the data block (N+4).
) can be instructed to hold up to.

As a result, continuous reading and re-reading of the same block can be made effective.

In addition, in this example, when the reference value T is 3 (
However, the explanation is not limited to this example, and the reference value T is 2 and I
-, or the reference value T may be arbitrarily set according to an instruction from the host computer.

[Effects of the Invention] As described below, according to the information reproducing apparatus of the present invention, the instructing means instructs the holding means to transfer the data if the number of blocks is larger than a predetermined value based on the comparison result of the comparing means. The data from the next block following the last block of data to be transferred is retained, and if the number of blocks is smaller than the reference value, the data from the next block following this first block is retained, including the first block of data to be transferred. Since it is possible to instruct the data to be retained, it is possible to easily and reliably speed up the access operation to the information recording medium.

[Brief explanation of the drawing]

FIG. 1 shows a CD-1? which shows an embodiment of the present invention. ol, I A block diagram of the configuration of the playback device, FIGS. 2(a) and 2(b) are diagrams showing the data area held in the buffer memory of FIG. 1,
FIG. 3 is a diagram showing the data structure of a conventional CD-ROM system, and FIGS. 4 and 5 are diagrams showing the data area held in the buffer memory of FIG. 3. DESCRIPTION OF SYMBOLS 1...Disk, 2...Pickup, 3...Buffer memory, 4...Buffer memory control section, 5...
- Comparison section, 6... instruction section. Applicant Toshiba Corporation Patent Attorney Satoshi Suyama − Host Gu===ko L−2=> ■ [Figure 1 Figure 21 Audio Audio 3I (b) Figure

Claims (1)

[Claims] (1) Holding means for temporarily holding data read from an information recording medium block by block; Comparing means for comparing the number of blocks of the data transferred from the holding means with a reference value; Based on the comparison results, for the holding means,
If the number of blocks is larger than the reference value, the data from the next block following the last block of the transferred data is retained, and if the number of blocks is smaller than the reference value, the data to be transferred is 1. An information reproducing apparatus comprising: instruction means for instructing to hold data from the next block following the first block including the first block.