JP3462675B2 - Disk unit - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, a CD-R.
The present invention relates to a disk device such as a (compact disk recording) device, and particularly to a buffer memory circuit used in the disk device.

[0002]

2. Description of the Related Art Generally, when data is sent from a disk device to a host computer, a buffer memory for storing data in the disk device is provided.

A control method and a device which can shorten the access time of the disk device of the host computer by executing the data reading from the disk device and the data transfer to the host computer in parallel are conventionally known. (For example, Japanese Patent Laid-Open No. 2-59923).

Recently, in personal computers and the like,
CD-ROMs for reproducing data and CD-Rs for recording have been widely used.

The same buffer memory is used for both reproduction and recording.

A conventional CD-R disk device will be described with reference to the drawings.

FIG. 3 is a functional block diagram showing an example of the essential structure of a conventional CD-R disk device. In the figure, 1 is a drive device, 2 is a CPU, 3 is a buffer control / interface circuit, 4 is a buffer memory, 5 is a host computer, a solid line shows a data flow, and a broken line shows a control flow.

The data reproduced from the drive device 1 is
Through the buffer control interface circuit 3, once 蓄 Erareru in the buffer memory 4.

Next, the buffer control / interface circuit 3 reads data from the buffer memory 4 and sends the data to the host computer 5.

In this series of operations, the CPU 2 controls the drive device 1 and the buffer memory 4 under the command of the host computer 5.

By the way, the CPU 2 may control the drive device 1 to read out more than the data designated by the host computer 5.

[0012] In this case, the read data 蓄 Erare the buffer memory 4, when the host computer 5 has issued a commander next reading the data, rather than from the drive device 1, from the buffer memory 4 The data is directly sent to the host computer 5.

That is, since the drive device 1 is not operated during the second access, the host computer 5
From the side, the data access time is apparently very fast. This operation is called prefetch.

Generally, the buffer memory 4 has a DR
AM (Dynamic Random Access Memory) is used.

In order to transfer data to the host computer 5 almost continuously by the device shown in FIG. 3 when reproducing data, the capacity of the DRAM is required to be about 256 kB.

Next, the case of recording data will be described.

[0017] The data from the host computer 5, via the buffer control interface circuit 3, once 蓄 Erareru in the buffer memory 4.

Next, the buffer control / interface circuit 3 reads the data from the buffer memory 4 and sends the data to the drive device 1.

The drive unit 1 stores the sent data in a CD.
-Record at R.

As described above, when recording data on a CD-R, there is a case in which a long time (a large amount) of data such as audio data is recorded all at once.

[0021] In this case, and data transfer capability of the host computer 5, the operations of hard disk transfer data are gills 蓄, the data transfer rate from the host computer 5 may be reduced.

However, even in such a case, the drive device 1 must continue recording data at a constant speed.

The reason for this is that if data is interrupted during this recording, a recording error (called buffer underrun) will occur.

Therefore, a CD-R device generally requires a buffer memory having a larger capacity than that of a read-only CD-R device. For example, at present, it is general to mount a memory having a capacity of 1 MB or more.

In recent years, the recording and reproducing speeds of CD-Rs and CD-ROMs have been increasing year by year, and the higher the recording speed of the drive, the higher the possibility of occurrence of buffer underrun. Larger buffer memory is required.

Here, the operation of the conventional CD-R disc device during reproduction will be described with reference to a flow chart.

FIG. 4 is a flow chart showing the main processing flow at the time of reproduction in the conventional CD-R disc device. In the figure, # 1 to # 6 indicate steps.

At step # 1, the presence or absence of a data read command from the host computer 5 is monitored.

[0029] When there is a data read instruction, the flow advances to step # 2, specified data is checked whether the data are gills 蓄 the buffer memory 4.

[0030] If data that is gills 蓄 the buffer memory 4, at the next step # 3, and the drive device 1, reads the designated data from the CD-R.

[0031] In step ♯4, the read-out data, once proceed to 蓄 Ete step ♯5 in the buffer memory 4.

[0032] As a result of checking in the previous step # 2, the designated data, even when the data are gills 蓄 the buffer memory 4, the flow proceeds to step # 5.

In step # 5, the data is read from the buffer memory 4.

In step # 6, the read data is sent to the host computer 5, the process returns to step # 1 again, and the same processing is performed thereafter.

By the processing in steps # 1 to # 6 described above, a so-called prefetch operation is performed and high-speed data transfer is performed.

[0036]

As described in the above-mentioned conventional example, in the CD-R, when recording a long time (large amount) of data, if the data is interrupted during recording, a recording error (buffer under Run).

Therefore, 512 kByte to 2 MByte
A buffer memory capable of storing the data e is required, but the DRAM used in this case is expensive, which increases the cost of the device.

An object of the present invention is to realize a disk device capable of high speed recording operation without using an expensive large capacity DRAM.

[0039]

In [SUMMARY OF] of claim 1 the invention is connected to a host computer, the once disc apparatus which performs by e 蓄 recording or reproduction of data from the buffer memory data, the buffer memory, the first a buffer memory, this is composed of a first of the second buffer memory access time from the buffer memory is slow large capacity, 蓄 example data to said second buffer memory at the time of data recording, the at the time of data reproduction first Buffalo of 1
At the same time as storing data in memory, the host computer
Data other than that specified by the
Obtain 蓄 the read-ahead data in the second buffer memory out look.

[0040] In the invention of claim 2 is the disk <br/> apparatus of claim 1, wherein the first buffer memory is DRAM, the second buffer memory is a flash memory.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Reference Example In this reference example, two types of buffer memories are provided, and the buffer memories are selectively used for writing and reading data, and the first buffer memory is relatively fast and small. It is characterized in that a large capacity memory is used at a relatively low speed as the large capacity memory and the second buffer memory.

FIG. 1 is a functional block diagram showing an example of the main configuration of the disk device of the present invention.
The reference numerals in the figure are the same as those in FIG. 3, 6 indicates the second buffer memory, the thin solid line indicates the flow of recording data, and the thick solid line indicates the flow of reproduction data.

The disk device shown in FIG. 1 has a second buffer memory 6 in addition to the device shown in FIG.
The basic configuration is the same except that is added.

The second buffer memory 6 has the (first
Like the buffer memory 4), it is connected to the buffer control / interface circuit 3.

In this case, a NAND flash memory is used as the second buffer memory 6. This N
AND type flash memory has access time DRA
Although it is slower than M, it has a feature that the cell size can be made smaller, so that the cost is lower than the capacity.

For example, the transfer rate at the time of recording of the CD-R drive is 600 KB / sec at the double speed (when the recording is performed by rotating at twice the rotation number of the music CD).

On the other hand, the data read speed of the NAND type flash memory is about 2.1 MB / sec because it is about 32 bytes / 15 μsec.

Since writing / reading is performed at this speed, even if the transfer speed is half that speed, the CD
-Because it is a value larger than the transfer rate of 600 KB / sec at the time of recording of the R drive, it can be used as a buffer at the time of recording.

Therefore, in the disk device of FIG. 1, data is sent to the host computer 5 via the (first) buffer memory 4 as in the case of FIG.

As described above, the recording / reproducing speed of the CD-R drive is increasing year by year as in the case of the CD-ROM.
The buffer memory 4 has a DR that enables high-speed access.
I am using AM, but there is no particular problem.

Therefore, with the configuration shown in FIG. 1, a low-cost CD-R can be realized without using a high-speed buffer memory having a large capacity. Embodiment In the above reference example, a low-speed second buffer memory 6 is used for recording, a high-speed (first) buffer memory 4 is used for reproduction,
However, in this case, there is a problem that a large-capacity buffer memory is required to effectively perform the prefetch operation in the reproducing operation, and the apparatus becomes expensive. .

In this embodiment of the present invention, in the reproducing operation requiring two large capacity buffer memories,
The device is characterized in that the prefetch operation can be effectively performed with a low-cost device.

Also in this embodiment, the hardware configuration is the same as that shown in FIG.

[0054] At the same time obtain 蓄 data during reproduction (first) buffer memory 4, (in the previous prefetch operation, the data other than the designated data from the host computer 5 that has been read in advance) prefetching data, second 蓄 Eteoku of the buffer memory 6.

Then, when the next read command is given from the host computer 5, if the designated data matches the prefetch data, the CPU 2 operates the second buffer memory 6 without operating the drive device 1. The data is read and sent to the host computer 5.

As described above, the second buffer memory 6 is slower than the (first) buffer memory 4, but compared with the operation of reading from the drive device 1.
Much faster.

In addition, since the capacity is extremely large compared to the (first) buffer memory 4, the probability that the designated data from the host computer 5 matches (hits) the prefetch data is also high.

With this configuration, the average access time of data from the host computer 5 can be shortened and the cost can be reduced.

The above operation is shown in the flow chart.

FIG. 2 is a flow chart showing the main processing flow during data transfer according to the second embodiment of the disk device of the present invention. In the figure, # 1
1 to # 20 indicate steps.

In step # 11, the host computer 5
The presence or absence of a data read command from is monitored.

[0062] When there is a data read instruction, the process proceeds to step # 12, the designated data is checked whether the data are gills 蓄 (first) buffer memory 4.

The designated data is stored in the buffer memory 4.
When the data that has been gills 蓄, the process proceeds to step ♯16.

[0064] On the other hand, as a result of checking in the previous step # 12, if data that is gills 蓄 the buffer memory 4, at the next step # 13, the second buffer memory 6
To check whether the data has been gills 蓄 to.

[0065] The specified data, when the data being gills 蓄 in the second buffer memory 6, step ♯20
Go to.

In step # 20, the data is read from the second buffer memory 6, the read data is sent to the host computer 5 in step # 17, and the process proceeds to step # 18.

[0067] By contrast, if, as a result of checking in the previous step # 13, if data that is gills 蓄 in the second buffer memory 6, the next step # 14, and the drive device 1, Read the specified data from the CD-R.

At step # 15, the read data is
Once proceed to 蓄 Ete step ♯16 in the buffer memory 4.

In step # 16, the data is read from the buffer memory 4.

In step # 17, the read data is sent to the host computer 5.

In step # 18, the drive unit 1 is controlled to read the data other than the designated data from the CD-R (prefetch: prefetch operation).

[0072] In step # 19, the read data 蓄 Ete in the second buffer memory 6, again the previous step ♯1
Returning to 1, the same processing is performed thereafter.

By the processing in steps # 11 to # 20 described above, the data is read in advance according to the present embodiment, and high-speed data transfer is realized.

[0074]

In the disk apparatus of the present invention exhibits, at the time of reading, the data other than the specified data from the host computer, so that obtain 蓄 the second buffer memory of a large capacity at low cost.

The second buffer memory is slower than the (first) buffer memory, but much faster than the read operation from the drive device, and the second buffer memory is Since the capacity is large, the probability that the designated data from the host computer matches the prefetch data also increases.

Therefore, the average access time of data from the host computer can be shortened and the cost of the disk device can be reduced.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing an example of an embodiment of a main configuration of a disk device of the present invention.

FIG. 2 is a flowchart showing a main processing flow during data transfer according to the second embodiment of the disk device of the present invention.

FIG. 3 is a functional block diagram showing an example of a main part configuration of a conventional CD-R disk device.

FIG. 4 is a flowchart showing a main processing flow at the time of reproduction in the conventional CD-R disc device.

[Explanation of symbols]

1 drive device 2 CPU 3 buffer control / interface circuit 4 buffer memory 5 Host computer 6 Second buffer memory

Claims (2)

(57) [Claims] 1. A is connected to a host computer, in the disk apparatus for recording or reproducing data data is once e 蓄 the buffer memory, the buffer memory includes a first buffer memory, from the first buffer memory consists access the second buffer memory time is slow mass, 蓄 example data to said second buffer memory at the time of data recording, the at the time of data reproduction first buffer memory
Data is stored in the
Read data other than those specified from the prefetch data
Disk apparatus characterized by the obtaining 蓄 <br/> the preread data in the second buffer memory by. Wherein a first buffer memory DRAM, disk apparatus according to claim 1 Symbol mounting and said second buffer memory is a flash memory.