JPH043218A - Data writing method and device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a data writing method and an apparatus thereof;
More specifically, the present invention relates to a method and apparatus for writing data to a storage device such as a magnetic disk.

<Prior art and problems to be solved by the invention> Computer systems have traditionally used magnetic disks, floppy disks, etc. to store various data.
Storage devices such as disks, memory cards, and RAM disks are used. And these storage devices are
It is designed to store a certain amount of information as a unit. Specifically, for example, 256 bytes, 512 bytes, 1024 bytes, etc. are set as one unit of information amount.

Therefore, if processing is interrupted due to a power failure etc. while writing information for one storage unit, the information for that storage unit will become incomplete, and the integrity of the data itself written to the storage device will be compromised. It will no longer be guaranteed.

Furthermore, when writing is being performed on a removable storage device such as a floppy disk or memory card, there is a possibility that the storage medium may be removed while writing one storage unit of information. Even if a storage unit is removed, the integrity of the data in the corresponding storage unit cannot be guaranteed.

To explain in more detail, as shown in FIG. 4, the storage device has a data area in which the data itself is stored, and a pointer indicating the identification name, bus, data size, and storage address of each data. The required access time can be shortened by first searching the directory area, reading the pointer, and then accessing the corresponding data itself. In addition, numerically speaking, if the data is up to 256 bytes in length, the integrity of data writing is ensured regardless of the occurrence of a power failure. Therefore, with such a device, the integrity of the entire data can be guaranteed by performing the following processing every time data is written in one storage unit. That is, ■ write a copy of the write data to a preset first area; ■ write the directory status, address of the write data,
Writes information indicating whether writing is complete or not to the randomly set second area, ■ writes the data to the corresponding address, ■ writes the directory, and ■ finally writes the data written to the second area. The information indicating whether or not the writing is completed is changed to the information indicating that the writing is completed, and then the information is written.

By performing this series of processes, even if a power failure or removal of the storage medium occurs in step 2, it is possible to restore the data by referring to the information written in step 2.

However, if such a series of processes is to be performed for each storage unit, it is necessary to add special circuits and devices to ensure data integrity when writing data for one storage unit. This increases the cost of the entire system.

<Object of the invention> This invention was made in view of the above problems,
The present invention relates to a novel data writing method and device that can ensure the integrity of written data without using any special circuit or device for ensuring the integrity of writing.

Means for Solving the Problems> In order to achieve the above object, the pig writing method of the present invention includes a storage means, a data area in which the data itself is written, and data information allocated for each written data. It is divided into a data information storage area to be written and a flag area to write a flag indicating whether writing of the data itself or pig information has been completed, and if processing is interrupted or occurs while writing data to the storage means. In this case, it is determined whether or not the data itself written in the data area is normal based on the flag, and only when it is determined that the data is not normal, the data itself is written to the storage means after the above processing is interrupted. be.

In order to achieve the above object, the data writing device of the present invention has a data area for writing data, a data information storage area for writing data information allocated for each written data, and a data storage area for writing the data itself. a storage means divided into a flag area for writing a flag indicating whether or not writing of data information is completed; a writing means for writing predetermined data into the corresponding area of the storage means; and an interruption of processing in the middle of writing data to the storage means. An interruption detection means detects that a process has occurred, and on the condition that the interruption detection means detects that a processing interruption has occurred, it is determined whether the data itself written to the data area is normal or not based on the corresponding flag in the flag area. The control means includes a determining means for determining whether or not the processing is normal, and a control means for writing the data itself into the storage means after the above processing is interrupted, on the condition that the determining means determines that the data is not normal.

With the above data writing method, the storage means is divided into a data area where the data itself is written, a data information storage area where data information allocated for each written data is written, and a storage area where writing of the data itself is completed. First, data information is written, and if the data information writing is completed successfully, the flag area is divided into a flag area where a flag indicating whether writing of data information is completed is written. is set to data indicating that the process has been completed and written to the flag area. Next, the data itself is written, and if the writing of the data itself is performed normally, a flag is set to data indicating that the writing of the data itself has been completed, and is written in the flag area. In this case, if the flag is read correctly, a predetermined processing procedure may be executed. In this case, if a power failure, removal of the storage medium, etc. occurs during writing of one storage unit including the flag, and the flag is not written correctly, the data information area and the data itself are also written correctly. The integrity of the data is guaranteed even if the flag is determined to indicate completion of data writing or if the data is written again based on the data information.

If the data writing device has the above configuration, there is a data area where the data itself is written, a data information storage area where data information allocated for each written data is written, and a data information storage area where the writing of the data itself is completed. First, the writing means writes data information into the storage means divided into a flag area in which a flag indicating whether the data is completed is written, and if the data information has been written normally, the writing means ,
A flag indicating that writing of data information is completed is written in the flag area. Next, the writing means writes the data itself, and if the writing of the data itself is performed normally, a flag indicating that the writing of the data itself is completed is written in the flag area.

If a processing interruption occurs due to a power failure or the like while performing the above series of processing, the interruption detection means can detect the interruption of the processing, and the discriminating means will determine whether the processing is stopped based on the flag. Determine whether the integrity of the interrupted data is guaranteed. In other words, if the flag indicates that writing of the data itself has been completed, it means that not only the data information but also the data itself has been completely written; conversely, the flag indicates that writing of the data information has been completed. If the data indicates , it can be seen that only the data information has been completely written, and the data itself has not been completely written. Therefore, when the latter determination result is obtained, the control means controls the writing means to rewrite the data itself based on the completely written data information, so that the integrity of the data can be ensured.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

Figure 2 shows storage media (1) (floppy disk, magnetic disk,
This is a diagram schematically showing the allocation of a magneto-optical disk (such as a magneto-optical disk), and shows the data area (1a) in which the data itself is written, the identification name, node, data size, and storage address of the data corresponding to the data itself. It is divided into a data information area (lb) in which data information such as a pointer is written, and a flag area (1c) in which a flag indicating whether writing of the data itself or data information is completed is written.

FIG. 1 is a flowchart showing an embodiment of the data writing method of the present invention, and FIG. 1(A) shows a case where the writing process is not interrupted due to power abnormality or the like. In step (2), writing is performed to the data information area (1b), and when the writing is completed, in step (2), a flag (for example, “1 Next, the data itself is written to the data area (1a) in step ■, and when the writing is completed, step
In this step, a flag (for example, a "0° flag") indicating that writing of the data itself has been completed is written to the corresponding address (the same address as in step 2) of the flag area (]C).

And if there is other data to write,
Repeat the above series of processes. Note that "0" is assigned to the above flag as an initial value.

FIG. 1(B) shows the processing when the write processing is interrupted.

If the write process is no longer interrupted, proceed to step ■
It is determined whether the flag is "0°" or "1'", and if it is "Y°", only the data information is completely written, and the data itself is not completely written. Therefore, in step (2), the data is The corresponding data itself is written based on the information, and the flag is set to "O" in step (3).

Set it to end the series of processing. On the other hand, if the angle is "0°," the data written in the data area is complete, so the process ends.

To explain in more detail, if processing is interrupted while data information is being updated (see step ■ in Figure 1 (A)), the flag is "0" and the data itself is complete (however, the updated (previous complete state), there is no need to recover the data itself.

Updating the data itself (see step ■ in Figure 1 (A))
If a processing interruption occurs, the flag is "1" and the data itself is incomplete.

However, since the data information is complete, the data itself can be made complete by updating the data itself again based on the data information.

If processing is interrupted when writing the flag in step (2) in Figure 1 (A), if the flag is "0", the data itself is complete (however, it is in the complete state before updating).
Data itself does not need to be recovered. vice versa,
If the flag is "1°," the data information has been completely written, so the data itself can be completely updated by updating the data itself based on the data information.

If processing is interrupted when writing the flag in step (2) in Figure 1 (A), if the flag is "0", the data itself is complete (however, it is in a complete state after updating)
Data itself does not need to be recovered. vice versa,
Even if the flag is "1°," the data information has been completely written, so the data itself can be made complete by updating the data itself based on the data information.

FIG. 3 is a block diagram showing an embodiment of the data writing device of the present invention, which includes an identification section (2) that receives data to be written and identifies data information and the data itself, and an identification section (2) that receives data to be written and identifies the data information and the data itself; The writing unit (3) receives and writes the data itself in this order to the corresponding address of the storage medium (1), and the writing unit (3) confirms that the writing of data information has been completed and that the writing of the data itself has been completed. An end detection unit (4) that detects the completion of writing, a flag output unit (5) that supplies a flag of “1°” or “0” to the write unit (3) in accordance with the type of data for which the end of writing has been detected, and a power source. An interruption detection unit (6) that detects that the writing process has been interrupted due to an abnormality, etc., and a flag reading unit that reads the flag from the flag area of the storage medium (1) when the process is resumed on the condition that the interruption has occurred. σ)
and a determination unit S) that determines whether or not it is necessary to update the data itself based on the read flag, and a determination unit S) that determines whether or not it is necessary to update the data itself based on the read flag; ), and a control unit (9) that causes the data itself to be written again based on the data information read from the data information area (1b).

The operation of the data writing device having the above configuration is as follows.

When data to be written is sent, first, the data information and the data itself are identified in the identification section (2), and the identified data information and the data itself are supplied in this order to the writing section (3). , storage medium (
Writing to the data information area (1b) of 1) is performed. Writing in this case is performed in units of a predetermined writing unit length. Since writing of data information is completed first, the end detection unit (4
) detects the end of writing, and the flag output section (5)
Flag 1 indicates that writing of data information has finished.
' is supplied to the writing unit (3), so the storage medium (1)
A flag 1' is written in the flag area (1c).

Next, the identified data itself is supplied to the writing unit (3), so that writing to the data area (1a) of the storage medium (1) is performed for each predetermined writing unit length. When the writing of the data itself is completed, the end detection section (4) detects whether the writing is completed, and the flag output section (5) sends a flag 0" indicating that the writing of the data itself has been completed to the writing section (3). Therefore, the flag O° is written in the flag area (lc) of the storage medium (1).

Thereafter, the above operation is repeated every time data writing is instructed.

Also, during the above series of processing, a power failure may occur.
If processing is interrupted due to removal of the storage medium itself, etc., the interrupted processing can be recognized by the interruption detection unit (6), so that processing can be resumed when the corresponding cause is resolved. I can do it. In this case, first, the flag is read out by the flag reading section (7),
In the control unit (8), it is determined whether or not the data itself should be written again based on the read flag, and if it is determined that the data itself should be written again (if the flag is "1").
The data information area (i
The data itself is stored in the data area (1a) based on the information in b).
can be written to ensure data integrity.

On the other hand, if it is determined that the flag is "0", the data integrity is already ensured, so the write process is not performed again.

<Effects of the Invention> As described above, the first invention identifies whether the writing of data information or the writing of the data itself has been completed using a flag that can ensure the integrity of data regardless of the interruption of the writing process. This feature makes it possible to reliably identify whether or not to write again due to processing interruption, and to ensure the integrity of written data without adding special circuits or devices. It has the effect of

The second invention also makes it possible to identify whether the writing of data information or the writing of the data itself has been completed using a flag that can ensure the integrity of the data regardless of the interruption of the writing process. This has the unique effect of being able to reliably identify whether or not to write again due to an interruption, and ensuring the integrity of written data without adding any special circuits or devices.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of the data writing method of the present invention, FIG. 2 is a diagram schematically showing allocation of storage media to which the data writing method of the invention is applied, and FIG. 3 is a flowchart showing an embodiment of the data writing method of the present invention. FIG. 4 is a block diagram showing the actual configuration of a data writing device. FIG. 4 is a diagram schematically showing the conventional allocation of storage media.

Claims (1)

[Claims] 1. The storage means (1) includes a data area (1a) in which the data itself is written, a data information storage area (1b) in which data information allocated for each written data is written, and the data itself. The flag area (1c) is divided into a flag area (1c) in which a flag indicating whether the writing of data has been completed or whether the writing of data information has been completed. Based on the flag, it is determined whether the data itself written to the data area (1a) is normal or not, and only when it is determined that it is not normal, the data itself is written to the storage means (1) after the above processing is interrupted. A data writing method characterized by: 2. A data area (1a) where data itself is written, a data information storage area (1b) where data information allocated for each written data is written, and a data area (1b) where writing of the data itself is completed or writing of data information is completed. A storage means (1) is divided into a flag area (1c) for writing a flag indicating whether the An interruption detection means (6) detects that an interruption of processing has occurred during data writing, and a flag area (1c) is set on the condition that the interruption detection means (6) detects that an interruption of processing has occurred. A determining means (8) for determining whether the data itself written in the data area (1a) is normal based on the corresponding flag, and a storage means for determining whether the data itself is normal or not based on the determining means (8). A data writing device comprising: (1) a control means (9) for causing the writing of data itself to be performed after the above-mentioned processing is interrupted.