JPH0785608A - Storage device - Google Patents

Abstract

PURPOSE:To provide a storage device capable of surely verifying that data are accurately stored in the storage device. CONSTITUTION:This device is provided with memory arrays 12 and 14 for storing inputted data and encoded data, the encoded data read from a storing mechanism 11 ares compared with data used for writing by a comparator circuit 18, and the coded data are compared with them by a comparator circuit 19. In the case when compared results from the comparator circuits 18 and 19 are matched with each other, it is judged that data are accurately stored in a recording medium by an error operation detecting circuit. The encoded data written in the recording medium by one head of a storage mechanism 11 having two heads are read by the other head, and the memory arrays 12 and 14 for storing plural set of data are provided, so that it is surely verified that data are accurately stored in the recording medium without reducing writing speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device, and more particularly to a storage device capable of surely verifying that data is written correctly.

[0002]

2. Description of the Related Art In an external storage device such as a computer,
A storage device using a recording medium such as a magnetic disk or an optical disk is used.

FIG. 4 shows a basic structure of a storage device using a recording medium. In this figure, the storage mechanism 31 is an apparatus including a recording medium and one head for writing data to the recording medium and reading information from the recording medium. The encoding circuit 33 and the modulation circuit 34 are circuits for writing information on a recording medium, and the demodulation circuit 35 and the decoding circuit 36 are circuits for reading information. The controller 39 is a circuit that is in charge of information transfer with a host (not shown) and timing adjustment of each circuit. The operation of the storage device using a magnetic disk medium as a recording medium will be briefly described with reference to FIG. First, the operation of storing data will be described.

The data transferred from the host as data to be stored is input to the encoding circuit 33 via the controller 39. The encoding circuit 33 creates an error detection and correction code based on the input data, adds the created error detection and correction code to the input data, and outputs it to the modulation circuit 34. In the following description, the data to which the error detection and correction code is added will be referred to as encoded data. The modulation circuit 34 converts the input coded data into
Modulate into a form suitable for writing on a recording medium. The storage mechanism 31 supplies an electric signal corresponding to the modulation signal output from the modulation circuit 34 to a head provided therein, thereby forming a magnetization reversal pattern corresponding to the modulation signal on the recording medium. The writing operation is completed by forming the magnetization reversal pattern (recording pattern).

The reading of data from the recording medium is performed as follows. First, the magnetization reversal pattern on the recording medium is converted into an electric signal by the head that has written the recording pattern. The demodulation circuit 35 performs the inverse conversion of the conversion in the modulation circuit 34 on the electric signal, and outputs the encoded data. If there is an error in the data, the decoding circuit 36 corrects the error based on the error detection / correction code in the decoded data, and outputs the corrected data. The error correction capability of the error detection / correction code depends on the number of bits (ratio of the number of data bits). In the storage device, an error detection / correction code having a bit number is usually selected so that the probability that an error exists in the read data is a certain value or less.

As described above, in the conventional storage device, the error detection / correction code is added so that the probability that an error exists in the read data is equal to or less than a predetermined value. But,
The correction performed using this code is a self-correction and does not determine whether the reading is performed according to the written data. Therefore, when important data is stored in a conventional storage device, the transferred data is stored on the host side and the data is compared with the read data to ensure that the data is accurate. I was verifying that it was remembered by.

Further, instead of such data verification,
Japanese Patent Laid-Open No. 62-252580 for verifying a circuit system.
There is a device proposed in the publication. This storage device
The circuit is verified by forming a loop with the circuit excluding the memory mechanism and determining whether the loop is functioning normally.

FIG. 5 shows an outline of a storage device disclosed in Japanese Patent Laid-Open No. 62-252580. This storage device serves as a recording system for recording on a storage mechanism 31 using a recording medium.
A memory 32, an encoding circuit 33, and a modulation circuit 34 are provided, and a demodulation circuit 35 and a decoding circuit 36 are provided as a reproduction system. A loopback switching circuit 37 is provided between the storage device 31, the modulation circuit 34, and the demodulation circuit 25, and a comparison circuit 38 for comparing the outputs of the memory 32 and the decoding circuit 36.
Is provided. The controller 39 transfers information with a host (not shown) and adjusts the timing of each circuit.

When the circuit system is verified, the loopback switching circuit 37 is used and the storage mechanism 31 is not used.
A loop of the recording system and the reproducing system is formed. The data input for verification is stored in the memory 32 and
It is sent to the encoding circuit 33, where the error detection and correction code is added. After that, the signal is modulated by the modulation circuit 34, passes through the loopback switching circuit 37, is demodulated by the demodulation circuit 35, and the decoding circuit 36 performs error detection and correction. Then, the corrected data and the data that is the basis of the data in the memory 32 are compared by the comparison circuit 38 to determine whether or not the circuit in the loop is functioning normally. There is.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the apparatus described in JP-A-2-252580, only the circuit system is checked without recording the data on the recording medium, so that it cannot be verified whether the data is accurately stored on the recording medium. There is a problem.

In the conventional data verification by comparing the data used for writing with the data read out, the verification is performed after error detection and correction. Therefore, even if an abnormality occurs in the modulation circuit, the recording medium, or the demodulation circuit, the abnormality may not appear in the table. In other words, the error detection and correction is such that a recording pattern corresponding to the input data is not formed due to defects on the recording medium, jitter or noise in the storage mechanism, or the original data cannot be read from the recording pattern. All errors (if possible) caused by the absence
I will correct it. Among these, errors due to jitter and noise occur irregularly and should be corrected. However, an error due to a medium defect means that the data is not stored correctly. Also,
Depending on the type of media defect,
In some cases, the defects may spread to other storage areas and the stored data may be lost. In traditional data validation,
As described above, even if the data is not accurately stored, there is a risk that the data is erroneously determined to be normal and, as a result, a serious failure may occur.

Therefore, an object of the present invention is to provide a storage device for confirming that the data is surely stored in the recording medium when writing the data.

[0013]

The invention according to claim 1 is
A storage medium having a recording medium, a first head for writing data to the recording medium, a second head for reading data from the recording medium, and a plurality of data to be written in the storage mechanism are stored. Encoding for generating an error detection and correction code that is a code for error detection and error correction based on the first storage means and the data, and outputting encoded data in which the created error detection and correction code is added to the data Means, a second storage means for storing a plurality of encoded data output by the encoding means, and a modulation data obtained by modulating the encoded data, written into a recording medium by using the first head. The writing means and the modulation data written by the writing means are read using the second head,
The reading means for demodulating and outputting the coded data and the coded data which is the basis of the coded data read by the reading means are searched from the second storage means, and the searched coded data and the reading means read out. Error detection and error correction using the first determination means for determining whether or not the encoded data that has been matched and the error detection and correction code in the encoded data read by the reading means are performed. The decoding means for outputting the data obtained by removing the data from the first storage means are searched for the data which is the basis of the data output by the decoding means, and the searched data and the data output by the decoding means match. The second determination means for determining whether or not the data is received, and the determination results of the first determination means and the second determination means are received, and if the two determination results both indicate a match, the data Is accurate Comprising a determining means for determining the stored.

That is, according to the first aspect of the present invention, for example, a data writable recording medium such as a magnetic disk medium or an optical disk medium can be simultaneously accessed.
Using a memory mechanism with two heads
First and second storage means for temporarily storing data in one process are provided, and it is confirmed that the data has been reliably stored by comparing the read data with the data in the corresponding write system. It should be noted that the two heads of the storage mechanism do not have to be able to move independently, and as long as they can read and write independently, for example, one slider may be provided with two heads.

The first storage means is used to store a plurality of data of the processing unit length as it is, and is composed of, for example, a memory array or a multistage latch circuit. The error detection and correction code is added to the data by the encoding means, the data is stored in the second storage means, and the data is supplied to the writing means. The writing means modulates the encoded data into a signal suitable for storage in the recording medium, and drives the head of the storage mechanism with the signal to generate encoded data such as a magnetization reversal pattern on the recording medium. A corresponding recording pattern is formed. Here, the encoded data refers to data to which the error detection and correction code is added.

The reading means converts the recording pattern on the recording medium into an electric signal, demodulates it to encoded data, and outputs the encoded data to the first judging means and the decoding circuit. The first determination means searches the second storage means for the encoded data which is the basis of the read encoded data,
Matching or non-matching between the retrieved encoded data and the read encoded data is determined. The decoding means corrects the detected error based on the error detection / correction code in the read encoded data, and outputs the data without the error detection / correction code. The second determination means searches the first storage means for the data that is the basis of this data, and determines whether or not the two data match. The determination results of the first and second determining means are output to the determining means, and the determining means determines that the data is accurately stored in the recording medium only when the two determining means both determine a match. However, in other cases, it is determined, for example, that the storage mechanism is malfunctioning according to the determination results.

As described above, since the encoded data used for writing and the encoded data read out before the error detection and correction by the decoding circuit are also performed, the data recording medium is also compared. It is possible to reliably verify that the data is correctly stored. Further, the storage mechanism having two heads and the first and second storage means capable of storing a plurality of data enable writing of data to the recording medium at the same timing as the normal writing operation.

According to a second aspect of the present invention, there is provided a storage mechanism comprising a recording medium, a first head for writing data on the recording medium, and a second head for reading data from the recording medium, First storage means for storing data to be written in the storage mechanism, and error detection and correction code which is a code for error detection and error correction based on the data,
Coding means for outputting coded data in which the created error detection and correction code is added to the data, second storage means for storing the coded data output by this coding means, and the coded data are modulated. Writing means for writing the modulated data on the recording medium by using the first head, and the modulated data written by the writing means is read by using the second head and demodulated into encoded data. The read means for outputting the read data, the first judging means for judging whether or not the coded data read by the read means and the coded data stored in the second storage means match, and the read means. Decoding means for performing error detection and error correction using the error detection and correction code in the read encoded data, and outputting data without the error detection and correction code, and data output by this decoding means The second judgment means for judging whether or not the data stored in the first storage means agree with each other, and the judgment results of the first judgment means and the second judgment means, and the two judgments are made. And determining means for determining that the data has been correctly stored when the results both show a match.

That is, in the invention according to claim 2, the first
And, as the second storage means, the data of the processing unit length is 1
By using a storage means which can be stored, such as a latch circuit, the data in the storage means provided before and after the encoding means is compared with the corresponding data in the reading system. The judging means judges that the data is accurately stored in the recording medium only when the two judging means judge the coincidence, and in other cases, for example, according to the judgment results, Make a decision that the memory is malfunctioning. As described above, since the encoded data used for writing and the encoded data read out before the error detection and correction by the decoding circuit are also compared, the data is accurately recorded on the recording medium. The stored information can be surely verified.

According to the third aspect of the present invention, there is provided a recording medium, a storage mechanism having a head for writing data to the recording medium, and a head for reading data from the recording medium, and data to be written in the storage mechanism. First storage means for storing, a coding circuit for creating a code for error detection and error correction based on the data, and outputting coded data in which the created error detection and correction code is added to the data, and Second storage means for storing the encoded data output by the encoding means, writing means for writing the modulated data obtained by modulating the encoded data in a recording medium, and the modulated data written by the writing means The reading unit that reads out, demodulates into encoded data, and outputs the encoded data, the encoded data read by the reading unit, and the encoded data stored in the second storage unit. Error detection and error correction are performed using the first determination means for determining whether or not the error detection correction code is included in the encoded data read by the reading means, and the data without the error detection and correction code is output. Decoding means, a second judging means for judging whether or not the data output from the decoding means and the data stored in the first storing means match, the first judging means and the first judging means. The determination means for receiving the determination result of the second determination means and determining that the data is correctly stored when both of the two determination results indicate coincidence.

That is, according to the third aspect of the invention, as the storage mechanism, a storage mechanism for reading and writing with one head is used. Even with this configuration, since the encoded data used for writing and the encoded data read out before the error detection and correction by the decoding circuit are also compared, It is possible to reliably verify that the data is correctly stored in the recording medium.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples.

FIG. 1 shows the configuration of a storage device according to an embodiment of the present invention. In the storage device of the embodiment, the disk drive mechanism 11 having two heads is used as the storage mechanism.
To write data to the disk drive mechanism 11, the memory array 12, the error detection / correction coding circuit 13, the memory array 14, and the modulation circuit 15 are used. The memory array 12 is a memory that can store a plurality of data as a processing unit. The error detection / correction encoding circuit 13 creates an error detection / correction code based on the data input via the memory array 12, and outputs the data obtained by adding the error detection / correction code to the memory array 14. Circuit. In the following description, the data to which the error detection and correction code is added will be referred to as encoded data. Also,
The modulation circuit 15 modulates the encoded data supplied from the memory array 14 and supplies the modulated signal to the disk drive mechanism 11.

Reading data from the storage mechanism 11
This is performed by the demodulation circuit 16 and the error detection / correction decoding circuit 17. The demodulation circuit 16 is a circuit that performs the reverse operation of the modulation circuit 15. The error detection / correction decoding circuit 17 detects an error in the data based on the error detection / correction code in the encoded data. When an error is detected, the error detection / correction decoding circuit 17 corrects the data and removes the data from which the error detection / correction code is removed. This is the output circuit.

The storage device of the embodiment writes data while determining whether or not the data is surely stored in the recording medium. Two comparison circuits 18 are used for the determination.
And 19, and the malfunction detection circuit 20 is used. The comparison circuit 18 includes the output of the memory array 14 and the demodulation circuit 1
The output of 6 is input, and the comparison circuit 18 determines whether these outputs match and outputs the determination result to the malfunction detection circuit 20. The comparison circuit 19 compares the contents of the memory array 12 with the contents of the output of the error detection / correction circuit 17, and outputs the comparison result to the malfunction detection circuit 20. The malfunction detection circuit 20 determines whether or not the data is reliably stored in the storage medium based on these two determination results.

The data to be written in the recording medium is
The data is input to the memory array 12 from a host computer (not shown) via the controller 21. Also,
The judgment result of the malfunction detection circuit 20 is also the controller 2
1 to the host computer. Further, the controller 21 also selects the data to be compared from the plurality of data stored in the memory arrays 12 and 14.

With reference to the operation timing chart shown in FIG. 2 and mainly using FIG. 1, the operation of the memory device of the embodiment will be described below. It should be noted that FIG. 2 corresponds to S _A to S _F in FIG.
FIG. 6 is a timing diagram schematically showing a time change of a signal in a portion indicated by.

Data is input via the controller 21.
Then, the data "D₁Is written in the memory array 12.
Remembered, "D₁”Means that the data is
Until it is confirmed that the data has been accurately recorded in the storage device 11.
(Signal S_FTo “D₁Is output and the comparison is completed.
In memory array 12). In addition,
To the error detection / correction coding circuit 13 via the ray 12.
Data "D₂"," D ₃"Supply of the comparison completed
Will be executed without any. The error detection / correction coding circuit 13 is turned on.
Forced data "D₁Error detection and correction code "E
₁", Create the data" D₁To the memory array 14
After output, the created error detection and correction code "E₁Out
Force In FIG. 2, the data “D₁Error detection and correction code
"E₁The encoded data consisting of "₁+ E₁"
I am doing it.

The modulation circuit 15 receives the encoded data "D ₁
+ E ₁ ″ is modulated and supplied to the disk drive mechanism 11. A write circuit (not shown) provided in the disk drive mechanism 11 supplies a current corresponding to the input modulation signal to the write head. Then, the magnetization reversal pattern corresponding to the encoded data is formed on the recording medium.

The magnetization reversal pattern written on the recording medium is different from that of the write head by the read head.
It is converted into an electric signal and demodulated by the demodulation circuit 16 into coded data “D ₁ + E ₁ ”. The time difference "t" between the start of the signal S _{D and} the start of the signal S _E depends on the positional relationship between the write head and the read head. The read encoded data “D ₁ + E ₁ ” is output to the comparison circuit 18 and the error detection / correction decoding circuit 17. Comparison circuit 18
, Upon receiving the encoded data from the demodulation circuit 16, and compares the coded data "D ₁ + E _1", the encoded data "D ₁ + E _1" in the memory array 14 from which it based As a result, the signal “C ₁ ” corresponding to the match or mismatch is output to the malfunction detection circuit 20.

These two encoded data do not match.
If not, the disk drive mechanism 11 or the modulation circuit 15
Or the demodulator circuit 16 is malfunctioning or malfunctions due to noise
Is the case. Also, when this comparison is complete
Then, "D" in the memory array 14 ₁+ E₁"Is unnecessary
The area used for storage is released.

The coded data “D ₁ + E ₁ ” input to the error detection / correction decoding circuit 17 has an error in the data detected based on the error detection / correction code in the coded data, and the number of the errors is detected. If is a correctable number, then the error is corrected and only the data portion is output. Comparison circuit 1
9 compares this data “D ₁ ” with the data “D ₁ ” in the memory array 12 on which the data “D ₁ ” is based, and matches them.
The signal “C ₂ ” corresponding to the mismatch is output to the malfunction detection circuit 20.

The malfunction detection circuit 20 includes comparator circuits 18 and 1
The outline of the operation performed according to the content of the signal of 9 is shown below.

When the comparison circuits 18 and 19 both output the coincidence signal: In this case, since the storage devices are all normal and the data is correctly stored in the recording medium, the malfunction detection circuit 20 causes the controller 21 to Erase (rewrite) of "D ₁ " in the memory array 12 is permitted.

When the comparison circuit 18 outputs the non-coincidence signal and the comparison circuit 19 outputs the coincidence signal: In this case, there is a possibility that an abnormal access is generated in the storage area of the disk medium of the disk drive mechanism 11. . However, since there is a possibility of malfunction due to noise, the malfunction detection circuit 2
0 notifies the controller 21 of that fact, thereby disallowing rewriting of "D ₁ " in the memory array 12. When the access from the host is interrupted, the controller 21 writes the data in the same storage area using "D ₁ " in the memory array 12, and when the same comparison result is obtained again, the recording is performed. The substitution process is performed on the area and the data is moved to the newly assigned substitution area. If the coincidence signals can be obtained from the two comparison circuits by rewriting "D ₁ ", it is determined that the malfunction is caused by noise.

As described above, in the storage device of the embodiment, the device is configured to automatically perform the alternative process. However, without performing the alternative process, the disk is sent to the host via the controller 21. It may be configured to only notify that there is a possibility that an abnormal access has occurred in the storage area of the medium.

When the comparison circuit 19 outputs the non-coincidence signal: In this case, since the data is not accurately stored, the malfunction detection circuit 20 instructs the controller 21 to stop the data write operation and the comparison circuit 18 The controller 2 calculates the estimation result of the failure point according to the comparison result of
Notify the host via 1. That is, the comparison circuit 1
When 8 outputs the coincidence signal, the failure location is the error detection / correction circuit 13 or the error detection / correction decoding circuit 17
Therefore, the fact is notified. If the comparison circuit 18 outputs a mismatch signal, there is a high possibility that the disk drive mechanism 11 or the modulation circuit 15 or the demodulation circuit 16 has a fault, and this is notified.

In the storage device of the embodiment, the disk drive mechanism using the two independently movable heads is used as the storage mechanism, but the two heads do not need to be independently movable, and the data on the same track is not used. On the other hand, it is only necessary that they can be accessed independently. For example, by configuring a disk drive mechanism having a read / write mechanism in which two heads are incorporated in one slider, and making the head located behind the slider a read-only head,
The time difference “t” between the start of writing to the recording medium and the start of reading from the recording medium can be shortened, and a storage device that requires a small memory array capacity can also be configured. Further, although the memory device of the embodiment uses the memory array, it goes without saying that other memory means such as a multistage latch circuit may be used.

First Modification

In the apparatus of the embodiment, a memory array capable of storing a plurality of data is used in order not to reduce the access speed of the storage apparatus. However, in the storage apparatus of the modified example, only one data of the processing unit length is stored. Use a memory that does. The configuration of the storage device of the modification is the same as that of FIG. 1, except that the memory array is replaced with a memory, and therefore the description thereof is omitted.

FIG. 3 shows the operation timing of the storage device of the modified example. In the memory device of the embodiment, data can be continuously input, but in the memory device of the modification, it is necessary to supply the data to the comparison circuit until the comparison by the comparison circuit is completed. Therefore, until the comparison is completed, the contents of the memory 12 cannot be rewritten, and as shown by the signal S _A , there occurs a time when data cannot be accepted. However, since the write operation can be performed while confirming that the data is surely stored by the two comparison circuits, the reliability of the data is still very high. If two heads are incorporated in one slider as described above, the time difference "t" between S _D and S _E can be shortened, for example, reading can be started before the writing of data of the processing unit length is completed. Therefore, it is possible to shorten the time during which the data is not accepted.

Further, in the memory device of this modification, the data verification speed decreases the writing speed to the recording medium. Therefore, this verification operation is performed only when important data is stored. The device may be configured as follows.

Second modification

The storage device of the second modification uses a normal storage mechanism for reading and writing with one head, instead of the storage mechanism having two heads in the storage device of the first modification. The configuration of this storage device is also the same as that shown in FIG. 1, so description thereof will be omitted. The operation timing is also the same as that shown in FIG. 3, and the difference is that the time difference "t" between S _D and S _{E is} the time required for one rotation of the disk medium.

That is, even in the storage device of the second modification, the operating speed thereof is slower than that of the storage device of the embodiment or the first modification, but the data is accurately recorded. It is possible to reliably verify that the data is stored in the medium.

In the memory device of the second modified example, a memory capable of storing one data of the processing unit length was used to store the write-system data to be compared, but this memory is used as a memory array. Of course, the head of the storage mechanism may be configured to reduce the time it is not used for writing or reading. Further, as described in the first modification, the device may be configured so that the verification function is used only when writing important data.

[0047]

As described above, according to the first aspect of the present invention, at the time of writing data, the data in the writing system and the data in the corresponding reading system are provided at two places before and after the error detection / correction process. Therefore, it is possible to reliably verify that the data is accurately stored in the recording medium. Further, it is also possible to estimate the failure location from the determination results from the two comparison circuits. Further, since the storage means for storing a plurality of data to be compared is provided, it is possible to confirm that the data is accurately stored without lowering the write operation speed.

According to the second aspect of the invention, since the data in the write system and the data in the corresponding read system are compared at two places before and after the error detection and correction process at the time of writing the data, It is possible to reliably verify that the data is accurately stored in the recording medium. Further, it is also possible to estimate the failure location from the determination results from the two comparison circuits. Furthermore, since the storage mechanism having two heads is used, the time required to read the written data can be shortened.

According to the third aspect of the invention, since the data in the write system and the data in the corresponding read system are compared at two places before and after the error detection / correction process when writing data, It is possible to reliably verify that the data is accurately stored in the recording medium. Further, it is also possible to estimate the failure location from the determination results from the two comparison circuits.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a storage device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the timing of the operation of the storage device according to the embodiment.

FIG. 3 is a timing chart showing the timing of the operation of the storage device according to the first modification.

FIG. 4 is a block diagram showing a configuration of a storage device according to a conventional example.

FIG. 5 is a block diagram showing a configuration of a storage device that performs a circuit check by forming a loop without a storage mechanism according to a conventional example.

[Explanation of symbols]

11, 31 ... Storage mechanism, 12, 14 ... Memory array, 1
3 ... Error detection / correction coding circuit, 15, 34 ... Modulation circuit,
16, 35 ... Demodulation circuit, 17 ... Error detection / correction decoding circuit, 18, 19 ... Comparison circuit, 20 ... Malfunction detection circuit, 2
1, 39 ... Controller, 32 ... Memory, 33 ... Encoding circuit, 36 ... Decoding circuit, 37 ... Loopback switching circuit

Claims (3)

[Claims] 1. A storage mechanism comprising a recording medium, a first head for writing data to the recording medium, and a second head for reading data from the recording medium; and a storage mechanism to be written in the storage mechanism. First storage means for storing a plurality of data, an error detection and correction code which is a code for error detection and error correction is created based on the data, and the created error detection and correction code is added to the data Encoding means for outputting data, second storage means for storing a plurality of encoded data output by the encoding means, modulated data obtained by modulating the encoded data, using the first head Writing means for writing on the recording medium, and the modulation data written by the writing means,
Read-out means for reading using the second head, demodulating into coded data and outputting the coded data, and coded data as a basis of the coded data read by the read-out means are retrieved from the second storage means. Then, the first determination means for determining whether the searched encoded data and the encoded data read by the reading means match, and the error detection and correction code in the encoded data read by the reading means are used. Error detection and error correction are performed, and decoding means for outputting the data from which the error detection and correction code is removed, and the data which is the basis of the data output by this decoding means are searched from the first storage means, The second judgment means for judging whether the searched data and the data output by the decoding means match, and the two judgment results of the first judgment means and the second judgment means Size A storage device, comprising: a determination unit that determines that the data has been correctly stored when both the determination results show a match. 2. A storage mechanism comprising a recording medium, a first head for writing data to the recording medium, and a second head for reading data from the recording medium; and a storage mechanism to be written to the storage mechanism. First storage means for storing data, and an error detection and correction code, which is a code for error detection and error correction, is created based on the data, and encoded data obtained by adding the created error detection and correction code to the data is generated. Encoding means for outputting, second storage means for storing the encoded data output by the encoding means, and modulated data obtained by modulating the encoded data, using the first head, to record the data. Writing means for writing on the medium, and the modulation data written by the writing means,
A read unit that reads using the second head, demodulates into encoded data and outputs the encoded data, and the encoded data read by the reading unit and the encoded data stored in the second storage unit are integrated. Error detection and error correction using the error detection and correction code in the encoded data read by the reading means, and the data from which the error detection and correction code has been removed Decoding means for outputting, second judging means for judging whether or not the data outputted by the decoding means and the data stored in the first storing means match, the first judging means Means for receiving the determination results of the second determining means, and determining means for determining that the data has been correctly stored when both of the two determination results indicate coincidence. Memory apparatus. 3. A storage mechanism having a recording medium, a head for writing data to the recording medium, and reading data from the recording medium; and a first storage unit for storing data to be written in the storage mechanism. A storage unit, an encoding circuit that creates an error detection and error correction code based on the data, and outputs encoded data in which the created error detection and correction code is added to the data, and an output by this encoding unit Second storage means for storing the encoded data that has been written, writing means for writing modulated data obtained by modulating the encoded data in the recording medium, and reading the modulated data written by the writing means, The read means for demodulating and outputting the coded data, the coded data read by the read means, and the coded data stored in the second storage means match each other. Error detection and error correction are performed using the first determination means for determining whether or not the error detection and correction code in the encoded data read by the reading means is used, and the data from which the error detection and correction code is removed is removed. Decoding means for outputting, second judging means for judging whether or not the data outputted by the decoding means and the data stored in the first storing means match, the first judging means Means for receiving the determination results of the second determining means, and determining means for determining that the data has been correctly stored when both of the two determination results indicate coincidence. Storage device.