JP3192654B2 - Disk writing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a disk writing device for writing data to an optical disk.

(Prior Art) In recent years, the performance of computers has been remarkably improved with the development of semiconductor technology. With that, the amount of processing data is steadily increasing.
It handles data of about 0M bytes.

Recently, optical disks have been increasingly used as storage media for computers instead of magnetic tapes and magnetic disks. One of them is CD-ROM (Compact Disc Read Oni)
y Memory). This CD-ROM has several hundred times the capacity of a floppy disk, and has many advantages such as long life and low cost.

Furthermore, in the latter half of 1989, a writable CD standard (Orang Book) was proposed due to advances in materials and the like. This Orang Book is a rewritable MO (Magnet Opt
ical) disc and WO (Write Once), which allows only appending
It consists of two disc standards, and the rules for data structure, disc dimensions, optical characteristics, etc. are basically Red Book Yel
Compliant with low Book. After writing, the WO disk can be reproduced by a normal CD player or CD-ROM drive. The MO disk is a magneto-optical disk and can be reproduced only by a dedicated player.

By the way, an ordinary recordable or rewritable recording medium (magnetic tape, magnetic disk, etc.) is provided with an area called a gap between data sectors. This serves as a buffer band for preventing data destruction near the write start and end portions due to partial data rewrite.

On the other hand, there is no such sector gap in the above-mentioned Orang Book standard optical disc, and instead, when appending, several sectors near the boundary are used as gaps to prevent data corruption. .

FIG. 2 is a block diagram showing the configuration of a disk writing device for writing data to such an optical disk.

In the figure, 1 is an optical disk, 2 is a disk motor that drives the optical disk 1 to rotate, 3 is a motor control unit that controls the drive of the disk motor 2, 4 is an EFM encoder that writes data to the optical disk 1, and 5 is a motor control unit. 3 and E
A system control clock unit that generates a system clock used for the operation of the FM encoder 4. Also 6
Is a bus interface for controlling data transfer to and from the host computer, 7 is a buffer memory for temporarily storing data transferred from the host computer, and 8 is a system control microcomputer for controlling the entire apparatus as a whole. is there.

In this disk writing device, data transferred from a host computer is temporarily stored in a buffer memory 7 through a bus interface 6. After that, the system control microcomputer 8 captures the data write start timing on the optical disc 1 and sends a write command signal to the EFM encoder 4 and the buffer memory 7.

As a result, the EFM encoder 4 reads data from the buffer memory 7 at a speed corresponding to the system clock and writes the data on the optical disc 1.

During data writing to the optical disk 1, the system control microcomputer 8 continues to output a data transfer request to the host computer through the bus interface 6 so that the buffer memory 7 does not underflow. The data transfer rate at this time is generally 150 Kbytes / sec for a CD.

By the way, what is particularly important in the operation of the disk writing device is that data must be written to the optical disk 1 without interruption in one additional write process. For that purpose, data must always be supplied stably from the host computer to the disk writing device.

However, depending on the type of the host computer, the data transfer capability (speed) may be considerably faster or slower than the data transfer rate in the disk writing device, and as a result, the buffer memory 7 overflows or underflows, and the optical disk 1 The continuity of the above data may be lost.

(Problems to be Solved by the Invention) As described above, in the conventional disk writing device, a discontinuous portion occurs in the data on the optical disk due to the difference between the data writing speed to the optical disk and the data transfer capability of the host computer. There was fear.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a disk writing device capable of writing data seamlessly on an optical disk without being affected by the data transfer capability of a host computer.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, a disk writing apparatus according to the present invention includes: a disk motor configured to rotationally drive an optical disk;
Motor control means for controlling the driving of the disk motor; buffer memory for temporarily storing data transferred from the host computer; data writing means for reading data from the buffer memory and writing the data on an optical disk; Means for generating a system clock used in the operation of the means and the data writing means, and a free area in the buffer memory during data writing to the optical disk, and a change in the free area per unit time of the host computer. Means for estimating the data transfer rate and the optimum data write rate from the estimated data transfer rate of the host computer, and changing the frequency of the system clock output from the clock generating means so that writing is performed at the determined rate. Clock control means to control It is intended to comprise.

(Operation) In the disk writing apparatus of the present invention, the optimum data writing speed is obtained by estimating the data transfer speed of the host computer from the amount of change in the free area in the buffer memory during data writing to the optical disk. Since the frequency of the system clock is controlled so that the writing is performed by the, the data can be written seamlessly on the optical disk regardless of the data transfer capability of the host computer.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram for explaining the configuration of a disk writing device according to one embodiment of the present invention.

In the figure, 11 is an optical disk, 12 is a disk motor for driving the optical disk 11 for rotation, 13 is a motor controller for controlling the drive of the disk motor 12, and 14 is an EFM encoder for writing data to the optical disk 11. Reference numeral 15 denotes a system control clock unit capable of changing a frequency for generating a system clock used in the operation of the motor control unit 13 and the EFM encoder 14. 16 is a bus interface for controlling data transfer with the host computer,
Reference numeral 17 denotes a buffer memory for temporarily storing data transferred from the host computer, and reference numeral 18 denotes a system control microcomputer that controls the entire apparatus.

Next, the operation of the disk writing device will be described. First, the system control microcomputer 18 operates the bus interface 16 to write data at the maximum speed possible with this device.
A data transfer request is sent to the host computer through.

As a result, data is transferred from the host computer to the apparatus, and the transferred data is temporarily stored in the buffer memory 17 through the bus interface 16.

On the other hand, the system control microcomputer 18 sends a write command signal to the EFM encoder 14 and the buffer memory 17 by capturing the timing of starting to append data to the optical disc 11.

As a result, the EFM encoder 14 reads data from the buffer memory 17 at a speed corresponding to the system clock generated by the system control clock unit 15, and writes the data to the optical disk 11.

The system control microcomputer 18 monitors the free space in the buffer memory 17 while writing data to the optical disk 11, and determines the average data transfer capability (speed) of the host computer based on the amount of change in the free space per unit time. Guess. Then, the system control microcomputer 18 obtains an optimum data writing speed from the estimation result, and switches the frequency of the system clock output from the system control clock unit 15 so that data writing is actually performed at this speed.

Therefore, according to the disk writing device of this embodiment, even if there is a large difference between the data transfer capability of the host computer and the data writing speed of the disk writing device, it is possible to cause the buffer memory 17 to overflow or underflow. Thus, continuous data can be written on the optical disk 11.

By the way, it is the motor control unit 13 that becomes the largest bottlenet with respect to the change of the data write speed. That is, the motor control unit 13 can respond only on the order of several hundred milliseconds. Therefore, it is basically desirable that once the data writing speed is determined according to the capability of the host computer, it is not changed unnecessarily. For this purpose, it is preferable that the buffer memory 17 have a certain capacity (for example, about 1 Mbyte if the data transfer rate is 150 Kbytes / sec).

[Effect of the Invention] As described above, according to the disk writing apparatus of the present invention, it is possible to write data seamlessly to an optical disk regardless of the data transfer capability of the host computer.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining the configuration of a disk writing apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram for explaining the configuration of a conventional disk writing apparatus. 11 optical disk, 12 disk motor, 13 motor controller, 14 EFM encoder, 15 system control clock unit, 16 bus interface, 17
Buffer memory, 18 System control microcomputer.

Claims (1)

(57) [Claims] 1. A disk motor for rotating and driving an optical disk, a motor control means for controlling the drive of the disk motor, a buffer memory for temporarily storing data transferred from a host computer, Data writing means for reading and writing the data on the optical disc; clock generating means for generating a system clock used in the operation of the motor control means and the data writing means; and an empty space in the buffer memory during data writing on the optical disc. Means for monitoring the area and estimating the data transfer rate of the host computer from the amount of change in the free area per unit time; and finding and finding the optimum data write rate from the estimated data transfer rate of the host computer. Writing at the speed of the octopus Disk writing apparatus characterized by comprising a clock control means for controlling the frequency of the system clock output from said clock generating means so.