JPH0467468A - Writing control system for disk device - Google Patents

Abstract

PURPOSE:To prevent invalid data from being written to a disk medium and to prevent data from being damaged by inhibiting writing in a data underrun state. CONSTITUTION:A data buffer control part 11 possesses a host pointer 11a as the first counting means and a drive pointer 11b as the second counting means. Then, when the value of the host pointer 11a is larger than the value of the drive pointer 11b, a data underrun state is dissolved and writing is allowed by a writing allowing part 13. Thus, data writing to a disk medium 15 in the data underrun state is inhibited and invalid data is prevented from being written to the disk medium 15. Thus, the data damage of the disk medium 15 can be prevented.

Description

[Detailed Description of the Invention] [Summary] Regarding a write control method for a disk device that prevents data destruction in a disk device during data writing, writing in a data underrun state is prohibited and invalid data or data is written to a disk medium. A write control method for disk devices in which data transferred from a host device is stored in a data buffer, and data read in blocks from the data buffer is written to a disk medium, with the aim of preventing data from being destroyed. a first counting means that counts up each time one block of data is stored from the host device in the data buffer;
a second counting means that counts up each time a block of data is read and written to the disk medium;
write permission means for comparing the value of the counting means and the value of the second counting means and permitting writing to the disk medium only when the value of the first counting means is greater. do.

[Industrial application field]

The present invention relates to a write control method for a disk device, and more particularly, to a write control method for a disk device that prevents data destruction in the disk device during data writing.

For disk devices such as magnetic disk devices and optical disk devices, the data transfer speed from the host device is different from the data writing speed to the disk medium, so data from the host device is stored in a data buffer and transferred from the data buffer to the disk medium. Write data to. At this time, it is necessary to prevent invalid data from being written to the disk medium and being destroyed.

[Conventional technology]

Conventionally, even if the data for two blowers, which is the data writing unit, has not been transferred from the host device to the data buffer (a so-called data under-order state), when there is a write request from the disk medium, the data is stored in the data buffer. 1
A block of data is written to the disk medium, and after one block of data is transferred from the host device to the data buffer, it is rewritten to the disk medium.

[Invention or problem to be solved]

In the above conventional method, when data is written to a disk medium in a data underrun state, invalid data is written to a part of the written I block on the disk medium, and after this, the power is turned off. If the host device cannot retry (rewrite) due to a failure or the like, there is a problem in that the data on the disk medium remains destroyed due to writing of invalid data.

The present invention has been made in view of the above points, and provides a write control method for a disk device that prohibits writing in a data untarrun state to prevent invalid data from being written to a disk medium and data being destroyed. The purpose is to

[Means to solve the problem]

A write control method for a disk device according to the present invention stores data transferred from a host device in a data buffer, and writes data read in blocks from the data buffer to a disk medium.
A first counting means that counts up each time one block of data is stored from the host device in the data buffer, and a second counting means that counts up each time one block of data is read from the data buffer and written to the disk medium. counting means, and write permission means for comparing the value of the first counting means and the value of the second counting means and permitting writing to the disk medium only when the value of the first counting means is greater. [Function] In the present invention, writing is permitted after the value of the first counting means becomes larger than the value of the second counting means and the data underrun condition is resolved. Writing data to disk media during run state is prohibited.
Invalid data is prevented from being written to the disk medium, thereby preventing data from being destroyed on the disk medium.

〔Example〕

FIG. 1 shows a block diagram of an embodiment of a disk device according to the present invention.

In the figure, IO is an interface control unit that controls data transfer with the host device, 11 is a data buffer control unit that controls the data buffer 12, and 13 is a control unit that controls data transfer to the disk medium 14 when there is valid data in the data buffer 12. A write permission section 14 that permits writing is a formatting section that assists in writing and reading data to and from the disk medium 15.

The data transferred from the host device is transferred to the interface unit 10.
The data is supplied to the data buffer control section II, and written into the data buffer 12 by the data buffer control section 11.

The data buffer control section 11 has a host pointer jl a as a first counting means and a drive pointer 11b as a second counting means, and the data buffer control section 11 has a host pointer jl a as a first counting means and a drive pointer 11b as a second counting means. When data is stored in the buffer 12, the value of the host pointer 11a is counted up by "1" as shown in FIG.
Count up the value of b by "1".

When the format control unit 14 is ready for writing to the disk medium 15, it supplies the data buffer control unit 11 with an H-level transfer request signal REQDRV.

The write permission unit 13 has the configuration shown in FIG.
．． The terminal 21 supplies the values of the host pointer tea and the drive pointer 11b, respectively, and the transfer request signal REQDRV is supplied from the terminal 22. The conveyor circuit 23 compares the host pointer value and the drive pointer value, and only when the host pointer value is greater, generates a HI/HER signal and supplies it to the AND circuit 24. When the transfer request signal REQDRV is at H level, a transfer response signal ACKDRV of H level is generated, and this is supplied from the data buffer control unit 11 to the formant control unit 14.

The data buffer control unit 11 receives the transfer response signal ACKD.
When RV is at the H level, one block of data is read from the data buffer 12 and transferred to the format control unit 14, and the format control unit 14 receives the transfer response signal ACKDRV at the H level to read out data from the data buffer 12. Data for 11,072 minutes is written to the disk medium 15.

In this way, writing is permitted after the value of the host pointer 11a, which is the first counting means, becomes larger than the value of the drive pointer 11b, which is the second counting means, and the data underrun state is resolved. Data writing to the disk medium 15 in a data underrun state is prohibited, invalid data is prevented from being written to the disk medium 15, and data destruction of the disk medium is thereby prevented.

〔Effect of the invention〕

As described above, according to the write control method of the disk device of the present invention, writing in a data underrun state can be prohibited to prevent invalid data from being written to the disk medium.
This is extremely useful in practice as it can prevent the data on the disk medium from being destroyed.

FIG. 2 is a diagram for explaining the host pointer and drive pointer, and FIG. 3 is a block diagram of the write permission section.

In the figure, 10 is an interface section, 11 is a data buffer control unit; 12 is a data buffer; 13 is a write control unit; 14 is a format control unit; 15 is a disk medium shows.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of a disk device according to the present invention. Host pointers (each) m m+1 ↓ ↓ ? m m+1 Drive pointer? ? ? Diagram 2 to explain host pointer and drive pointer

Claims (1)

[Claims] Data transferred from a host device is stored in a data buffer (12
), and writes the data read in blocks from the data buffer (12) to the disk medium (15). a first counting means (11a) that counts up each time one block of data is stored; and a second counting means (11a) that counts up each time one block of data is read from the data buffer (12) and written to the disk medium (15). The value of the first counting means (11a) is compared with the value of the second counting means (11b), and the value of the first counting means (11a) is larger. Only when the disc media (
15) a write permission means (13) for permitting writing to a disk device;