JPH0428064A - Digital data recording and reproducing device - Google Patents

Abstract

PURPOSE:To detect an imperfect recording operation by providing an error detecting data comparing means for comparing a 1st error detecting additive data and a 2nd error detecting additive data. CONSTITUTION:The 1st error detecting additive data is generated to digital data to be recorded by a 1st error detecting data generating means (recording CRC data generating part) 8 according to a predetermined regulation, and the 1st error detecting additive data is temporarily stored by an error detecting data storage means (CRC data memory) 10. The 2nd error detecting additive data is generated to digital data reproduced by a data monitor means (CRC data memory address generator) 11 by a 2nd error detecting data generating means (reproducing CRC data generating part) 9 according to the same regulation as the 1st error detecting data generating means 8. The 1st error detecting additive data and the 2nd error detecting additive data are compared with each other by an error detecting data comparing means (CRC data comparing part) 12. By this method, an imperfect recording operation can be detected without comparing all data by read-after-write.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention corrects incomplete recording by immediately reproducing the recorded data while recording digital data and comparing the recorded digital data with the reproduced digital data. The present invention relates to a digital data recording and reproducing device that detects motion.

BACKGROUND OF THE INVENTION In recent years, as computers have become faster and larger in capacity and the amount of data they handle has increased, magnetic recording devices have also significantly increased in capacity and speed.

However, in these devices, it is basically essential that data be recorded and read out accurately, and devices have been devised so that it can be confirmed during the recording operation whether the recorded data has really been recorded correctly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of conventional digital data recording and reproducing apparatuses will be described below with reference to the drawings.

FIG. 3 is a block diagram showing the configuration of the conventional digital data recording/reproducing apparatus. In FIG. 3, 1 is a memory that temporarily stores digital data sent from an external device, and 2 is a memory that divides the digital data into groups that are data management units of a predetermined amount of data.
A signal processing unit stores each group in the memory 1 and performs code generation and code correction of an error correction code for each group. 3 is group data to which the signal processing unit 2 adds an error correction code to each group and outputs it. This is a recording and reproducing section that sequentially converts the data into recording signals and sequentially converts the reproduced signals into group data and sends them to the signal processing section 2.

4 is a recording head that writes signals to the recording medium, and 5 is a reproducing head that reads signals from the recording medium. 6 is a communication unit that transmits and receives digital data and control data to and from an external device. 14 is an address generator that calculates the physical address of the group data on the memory 1; 15 is the group data that the recording/reproducing section 3 simultaneously reproduced during the recording operation and the group data that remains on the memory 1 and corresponds to the reproduced data. This is a data comparison unit that receives as input and determines whether the two match.

16 is a signal processing section 2. Recording and reproducing section 3. Data comparison section 15
This is a control unit that controls the operation of the controller.

Regarding the conventional digital data recording and reproducing apparatus configured as described above, basic operations of recording and reproducing operations and practical operations regarding detection of incomplete recording operations will be explained.

First, the recording operation will be explained according to the flow of control. FIG. 4 is a flowchart showing the processing procedure of the control section 16. The control unit 16 recognizes control data given from an external device via the communication unit 6 in step 1, and determines whether the control data is for recording or reproduction in step 2. In the case of recording, the signal processing section 21 and data comparison section 15 are initialized in step 3, and the operation of the recording/reproducing section 3 is set to recording.

In step 4, the signal processing section 2 sequentially stores the digital data sent from the external device via the communication section 6 into the memory 1 as group data.

When the storage of the group data is completed, in step 5, the signal processing section 2 is instructed to generate an error correction code, and the signal processing section 2 adds the error correction code and redundant data to the group data. Further, the address generator 14 generates a physical address on the memory 1 of the designated group data every time the signal processing section 2 accesses the memory 1. When the code generation is completed, the digital data to be recorded on the recording medium is fixed on the memory 1. Next, in step 6, the signal processing unit 2 is instructed to transfer the group data to the recording/reproducing unit 3, and the signal processing unit 2 sequentially reads the group data from the memory 1 in a predetermined order and records and reproduces it as recorded data. Send to Department 3. The recording/reproducing section 3 sequentially converts the data into recording signals, and writes them onto a recording medium via the recording head 4. The recording operation is performed according to the flow described above.

Next, the playback operation will be explained. The processing flow of the reproducing operation is almost the reverse flow of the recording operation. If it is determined in step 2 that the control data is for reproduction, the process proceeds to step 7, where the signal processing section 2 is initialized and the operation of the recording/reproducing section 3 is set to reproduction. In step 8, the recording and reproducing unit 3 converts the reproduced signal read by the reproducing head 5 into group data, and sequentially transfers it as reproduced data to the signal processing unit 2, and the signal processing unit 2 sequentially writes the reproduced data to the memory 1. . When the original group data is reproduced on the memory 1 using the reproduced data, the signal processing unit 2 is instructed to perform error correction processing in step 8. The signal processing section 2 executes the processing, and when the error in the group data on the memory 1 is corrected, the group data is sequentially read out from the memory 1 in the same manner as recording in step 10, and the communication section 6
to an external device to complete the playback operation.

Next, detection of incomplete recording operation will be explained.

In the recording operation, a signal is written onto the recording medium via the recording head 4, and at the same time, the signal written by the recording head 4 is immediately monitored by the reproduction head 5. this"
Read After Write.” The playback signal immediately monitored by this read-after-write is
The recording/reproducing unit 3 converts the data into group data and outputs it in the same manner as the reproducing operation. At this time, unlike the reproduction operation, the signal processing section 2 does not receive the reproduction data, but the data comparison section 15 receives it. The data comparator 15 instructs the address generator 14 to read group data corresponding to reproduced data from among the recorded data remaining on the memory 1 and compare them. The data that should have been recorded in this way and the data that was actually recorded,
By comparing it with the reproduced data one byte at a time, it is determined whether or not it was recorded correctly. If the comparison results do not match, the control unit 16 guarantees a perfect recording operation by redoing the recording operation again.

Problems to be Solved by the Invention However, in the conventional configuration described above, the number of accesses to the memory in which the group data to be recorded is stored is limited to the number of accesses to the memory in which the group data to be recorded is stored. In addition to sending data to the recording/playback section,
Writing requires at least four accesses per byte when comparing recorded data and reproduced data; (1) It is difficult to increase the speed of the device due to memory throughput;

In addition, since the configuration requires that the group data itself be saved until the data comparison is completed by read-after-write, (2) memory usage efficiency due to the area where recorded data is saved; is degraded and requires a large amount of memory as a result.

(3) If the time from when the recorded data is sent to when the recorded data is played back and compared by the after-write process increases, the amount of group data that must be saved increases, requiring a large amount of memory. capacity is required.

There were problems such as.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide an digital data recording/reproducing device that can detect incomplete recording operations without comparing all recorded data by read-after-write. be.

Means for Solving the Problems In order to achieve the above object, the digital data recording and reproducing apparatus of the present invention includes a recorded data monitor that reproduces a digital signal recorded on a recording medium after recording a predetermined number of data, or immediately after recording a predetermined number of data. According to predetermined rules for the means and the digital data to be recorded, the first
a first error detection data generation means for generating additional data for error detection; an error detection data storage means for temporarily storing the first additional data for error detection; and digital data reproduced by the data monitor means. In contrast, second error detection data generation means generates second error detection additional data according to the same rules as the first error detection data generation means, and second error detection data generation means generates the first error from the error detection data storage means. error detection data comparison means for reading out the additional data for detection and comparing it with second additional data for error detection generated from the digital data reproduced by the second error detection data generation means; The first error detection data generation means and the second error detection data generation means are configured to use redundant data of the CRC code as additional data for error detection.

Effect of the Invention With the above-described configuration, the present invention reduces the total amount of stored data to be compared during read-after-write, and reduces the number of accesses to the memory.

Embodiment Hereinafter, an embodiment of the digital data recording/reproducing apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital data recording/reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, the same reference numerals are given to the parts having the same configuration as those of the conventional example described above, and the explanation thereof will be omitted. 7 is an address generator that generates a physical address on the memory 1 corresponding to the group data instructed by the signal processing unit 2; 8 is an address generator that encodes the recorded digital data with a cyclic code (hereinafter referred to as CRC code); A recording CRC data generation section 9 outputs redundant data, and a reproduction CRC 9 outputs redundant data of a CRC code using the same procedure as the recording CRC data generation section 8 for reproduction data monitored by read-after-write.
This is a data generation section. 10 is a recording CRC data generation unit 8
CRC that temporarily stores the recorded CRC data output by
a data memory 11; a CRC data memory address generator 12 for generating the address of the CRC data memory 10;
reads the reproduced CRC data output from the reproduced CRC data generation section 9 and the recorded CRC data stored in the CRC data memory 10 corresponding to the reproduced CRC data,
This is a CRC data comparison unit that performs a match comparison. 13 is a signal processing unit 2.13 according to control data obtained via the communication unit 6.
Recording and reproducing section 3. Recording CRC data generation section 8. playback CRC
This is a control unit that controls the operation of the data generation unit 9.

The operation of the digital data recording/reproducing apparatus configured as above will be explained below. Since the basic operations such as recording and reproducing operations are the same as those of the conventional example, the actual operation regarding detection of an incomplete recording operation, which is different from the conventional example, will be explained below.

First, the recording CRC data generation section 8 receives the recording data output from the signal processing section 2, divides the group data into several CRC code sequences, and encodes the CRC code using a predetermined number of recording data as a unit. I do. FIG. 2 shows an example of a CRC code encoder. In FIG. 2, 21 is a delay element, 22 is a coefficient (0 or 1) of a CRC code generation polynomial.
). 23 is a mod 2 adder that performs exclusive OR in logical operations. In other words, it is composed of a shift register and a FOR circuit. When recording data is sequentially input to this input, when a predetermined number of recording data have been input, each delay element 21 is
Redundant codes of the RC code remain. By extracting this, recording CRC data is generated, and this is stored in the CRC data memory 10. By repeating this process for all CRC code sequences, recording CRC data for the entire group data is generated and temporarily stored in the CRC data memory 10 via the CRC data memory address generator 11.

The reproduced CRC data generation section 9 monitors and reproduces the digital data recorded by read-after-write.
Recording C based on the reproduced data output from the recording/reproducing section 3
The reproduced CRC data is generated in exactly the same manner as the RC data generator 8, and the recorded CRC data temporarily stored in the CRC data memory 10 is read out and compared with the reproduced CRC data. Incomplete recording operation is detected by this coincidence and dispersion.

Here, the ability to detect an incomplete recording operation in this embodiment will be explained.

The CRC code generates redundant data of a predetermined length from original data. A case where exactly the same redundant data is generated even though the original data is different is a detection error due to an incomplete recording operation. The probability of its occurrence is as follows, where the original data length is N (bits) and the generated data length is M (bits).

The total number S of original data is 5=2N The total number T of data that generates the same redundant data is 'l'=
2N-N Therefore, the probability of occurrence P is: P=2"-"/2N=2-" As shown above, the probability of occurrence of a detection error depends only on the redundant data length, and if M is set to 64 bits (8 bytes), for example, Then
P≦l Q-19, which is sufficient for practical use.

Now, the capacity of the CRC data memory 10 in this embodiment will be explained. - For example, DAT (digital
Let us consider a case where a digital data recording/reproducing apparatus using an audio tape recorder is used, and the CRC code generates the above-mentioned 64-bit redundant data in units of data recorded in a DAT frame. That is, 8 bytes of CRC redundant data is generated for 5760 bytes of original frame data. Therefore, it is sufficient to temporarily store 1/720 of the data when comparing all the data as in the conventional example. Assuming that the delay time from recording by read-after-write until monitor playback and CRC data comparison is equivalent to 5 frames, it is only necessary to temporarily store 40 bytes of data in the CRC data memory 10. become.

As described above, according to this embodiment, in order to determine whether the data recorded by read-after-write has been correctly written, only the redundant data of the CRC code generated from the recorded or reproduced data is compared. This makes it possible to guarantee highly reliable recording operations even with a small memory capacity.

Effects of the Invention As described above, the digital data recording and reproducing apparatus of the present invention includes a main data storage means for temporarily storing digital data to be sent to and received from an external device, and a predetermined data management system for storing digital data on the main data storage means. a signal processing means for dividing the digital data into units and converting the digital data into a predetermined data format; a recording and reproducing means for recording and reproducing the digital data converted for each data management unit onto a recording medium; A recorded data monitoring means for reproducing the recorded digital signal after or immediately after recording a predetermined number of data;
a first error detection data generation means for generating additional data for error detection; an error detection data storage means for temporarily storing the first additional data for error detection; and digital data reproduced by the data monitor means. In contrast, second error detection data generation means generates second error detection additional data according to the same rules as the first error detection data generation means, and from the error detection data storage means,
error detection data comparison means for reading out the first error detection additional data and comparing it with second error detection additional data generated from the digital data reproduced by the second error detection data generation means; The first error detection data generation means and the second error detection data generation means compare all data by read-after-write by using the redundant data of the cRc code as additional data for error detection. By comparing a very small amount of CRC redundant data generated from data recorded or reproduced on a monitor, it is possible to practically detect incomplete recording operations.

In addition, since the number of accesses to the memory that records group data can be reduced, it is suitable for increasing the speed of H placement.
The effects are significant, such as improved memory usage efficiency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a digital data recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram showing the internal configuration of the CRC data generation section in FIG. 1, and FIG. FIG. 4 is a block diagram showing the configuration of a data recording and reproducing apparatus. FIG. 4 is a flowchart of processing of a control section in the conventional example shown in FIG. Engineering...Memory, 2...Signal processing unit, 3...
・Recording/reproducing section, 4... Recording head, 5...
Reproduction head, 6... Communication unit, 7... Address generator, 8... Recording CRC data generation unit, 9.
... Reproduction CRC data generation unit, 10... CRC data memory, 11... CRC data memory address generator, 12... CRC data comparison unit, 1
3... Control unit, 21... Delay element, 22.
... Multiplier, 23... Adder. Name of agent: Patent attorney Densuke Awano - Figure CRC redundant data input -

Claims (3)

[Claims] (1) A main data storage means for temporarily storing digital data sent from an external device, and a main data storage means that divides the digital data on the main data storage means into predetermined data management units, and stores data in advance for each data management unit. A signal processing means that converts digital data into a predetermined data format, and converts digital data into each data management unit.
A digital data recording and reproducing device comprising a recording and reproducing means for recording on or reproducing from a recording medium, and a recorded data monitoring means for reproducing a digital signal recorded on the recording medium after a predetermined number of data has been recorded or immediately. a first error detection data generating means for generating first error detection additional data according to a predetermined rule for digital data to be recorded; Error detection data storage means for temporarily storing second error detection additional data on the digital data reproduced by the recorded data monitor means according to the same rules as the first error detection data generation means. a second error detection data generating means for generating; and reading the first error detection additional data from the error detection data storage means, and generating the data from the digital data reproduced by the second error detection data generating means. A digital data recording/reproducing device comprising error detection data comparison means for comparing with second error detection additional data. (2) The recording and reproducing means records and reproduces digital data on a tape, which is a recording medium, in units of frames consisting of a pair of inclined tracks, and the first and second error detection data generating means record and reproduce digital data on the tape, which is a recording medium. 2. The digital data recording and reproducing apparatus according to claim 1, wherein additional data for error detection having a predetermined data length is generated in units of digital data recorded in the same frame. (3) The digital data recording/reproducing apparatus according to claim 1 or 2, wherein the first error detection data generation means and the second error detection data generation means use redundant data of a cyclic code as additional data for error detection.