RU111706U1 - LONG-TERM STORAGE DIGITAL STORAGE DEVICE - Google Patents

Abstract

 The device for monitoring the state of a long-term digital storage medium, which contains a series-connected preliminary circuit for processing the read signal, a demodulator, a deinterleaver, a syndrome calculator and a syndrome analyzer, a drive counter, also includes a block for calculating the probability of distorted characters, an analysis result display unit, a time interval setting unit analysis, the unit for setting the acceptable probability of the appearance of distorted characters, while the outputs of the unit for setting the time interval with the signals “0”, “start” and “stop” are connected to the inputs of the drive counter, the output of the drive counter is connected to one input of the probability calculation unit, and the output of the time interval setting unit with a signal of the total number of characters read in is connected to its other input during the analysis time, the output of the probability calculation unit is connected to one input of the analysis result display unit, and the output of the setting unit for the admissible probability of the appearance of distorted characters is connected to its other input.

Description

The inventive utility model relates to the field of digital recording, namely to monitor the status of recording media.

The accumulated amount of information in various fields of human activity - science, culture, technology - is huge, and the carriers of this information are short-lived: both paper and magnetic media are destroyed under the influence of light, humidity, temperature.

Thanks to the advent of optical recording, it has become possible to transfer valuable information for long-term storage to new media, namely optical discs. Such discs are CD, DVD, BD.

When recording information on disks of any format, it may distort due to defects in the medium itself.

From the patents of the Russian Federation No. 2192673, G11B 20/18, 1999; No. 2313136, G11B 7/004, 2004. Technical solutions are known that ensure the detection of defective media zones and the transfer of information directly during recording from defective zones to backup zones.

Known recording media include a recording area, a backup area, and a defect management information area that stores information indicating whether linear replacement is used to record data in real time. As a result of detection of defects in the recording, information is overwritten in the reserve zone.

Known technical solutions for optical disks of rewritable type and control devices for defective zones on them: US Pat. RF No. 2334289, G11B 20/18, 2003; No. 2346341, G11B 7/007, 2003; No. 2360300, G11B 7/00, 2003. They provide methods for detecting recording defects and devices for managing defective areas of BluRay discs. They also provide for recording data recorded in the defective area to another user data area and recording information about defect management related to the defective area to one defect management area.

However, during long-term storage of any medium or with careless handling of it on disks, distortion in the recorded data is inevitable due to the gradual destruction of the recording layer of the medium under the influence of temperature, humidity, illumination, the presence of active reagents in the air and other reasons. To save the recorded information, it is necessary to rewrite it on a new medium in time. If the number of errors in the reproduced data does not exceed the corrective capabilities of error-correcting codes, then all distortions due to the presence of media defects will be detected and corrected by Reed-Solomon decoders. However, the resistance to destruction of the recording layer in different discs is different and can vary by tens or hundreds of times, since it depends on the recording format, the chemical composition of the recording layer, the manufacturer of the disc, and the conditions for its storage and use. In the absence of a mechanism for controlling the number of media defects, determining the point in time when the media should be rewritten is not possible. At the same time, overly frequent rewriting of information - “just in case” - will lead to unreasonably high costs of time and money, and at sufficiently large intervals of rewriting (once every several years), the probability of irreparable loss of recorded data increases.

The author was faced with the task of developing a device for monitoring the state of long-term optical storage media in order to determine the need to overwrite the data contained on them on a new medium.

The task was solved as follows.

The inventive device comprises a series-connected pre-processing circuit for a signal read from a disk, a demodulator, a deinterleaver, a syndrome calculator, a syndrome analyzer, and a drive counter. A block for calculating the probability of occurrence of distorted symbols, a block for displaying the analysis result, a block for specifying an analysis time interval, and a block for setting the acceptable probability of distorted symbols are introduced into the device. The connections of the blocks are made as follows: the outputs of the block for specifying the analysis time interval with the signals “0”, “start” and “stop” are connected to the inputs of the counter-drive, the output of the counter-drive is connected to one input of the block for calculating the probability of occurrence of distorted characters, and to the other its input is connected to the output of the unit for setting the analysis time interval with signals of the total number of characters read during the analysis time, the output of the probability calculation unit is connected to one input of the display unit of the analysis result, and to Goma its input connected to the output unit setting allowable probability of corrupted symbols.

The essence of the proposed solution is to control the number of defects on the recording medium of any format (CD-R / RW / ROM, DVD-R / RW / RAM / ROM, BD-R / RE / ROM) by assessing the probability P _the appearance of distorted characters in the signal read from the carrier by analyzing the syndromes of Reed-Solomon codes and comparing the obtained probability value with the previously calculated critical value P _{search for} this parameter for the carrier of this format. If P _suit > P _suit.dop , then the information from this media should be rewritten on a new carrier, if P _suit <P _suit.add , then the carrier does not need to be rewritten.

The inventive device is presented in the form of a block diagram, where

1 - block setting the time interval of the analysis;

2 - counter drive;

3 - pre-processing unit of the read signal;

4 - demodulator;

5 - de-interleaving unit;

6 - a syndrome calculator;

7 - syndrome analyzer;

8 - probability calculation unit Risk;

9 - display unit of the analysis result (display);

10 - unit setting the allowable probability P _claims .

The device operates as follows. Before starting the analysis procedure, the value of the time interval during which the number of errors will be calculated and the probability of their occurrence (10 minutes, 1 hour, or another interval) is set on block 1 to set the time interval. This is necessary in order to set the total number of characters; which will be read from the controlled medium during the analysis time, and generate the signals “0”, “start” and “stop” at the right time.

The circuit is started by pressing the “start” button on block 1 of the task for the analysis time interval, and at the outputs of this block, “0” and “start” signals are generated, which first reset to zero, and then trigger the counter-drive 2. The signal read from the medium, arrives at the input of the preprocessing circuit 3, is processed in the usual way for this format and is fed to the input of the demodulator 4, and from the output of the demodulator 4 it is fed to the data deinterleaver block 5 before feeding them to the syndrome calculator block 6 of the first Reed-Solomon decoder (for the CD format, this is the C1 decoder) (see V.A. Nikamin. Digital sound recording formats, St. Petersburg: ELBI, 1998, pp. 58-74). The calculated syndromes contain comprehensive information about the number of errors in the decoded codeword, which is necessary to calculate the probability of the appearance of distorted characters in the stream of reproduced data. Further, the information is fed to the input of the analyzer 7 syndromes, which determines the number of detected errors and the information about it in the form of the corresponding number of pulses is transmitted to the input of the counter-drive 2.

At the end of a predetermined time interval, an output signal “stop” is generated at the output of block 1 for setting this interval, which stops the counter-accumulator 2 and fixes the number of errors accumulated during the analysis. This number is fed to the input of block 8 calculation of the probability P _lawsuit . At the same time, from the block 10 for setting the admissible probability of the appearance of distorted characters, a number characterizing the total number of characters read from the controlled medium during the analysis is supplied to another input of the block 8. Obtained as a result of the calculation, the probability value P _claim is submitted to the analysis result display unit 9 (digital display or computer monitor) and is compared with the preset allowable value P _claim . If the P _{claim is} less than the P _claim , then the green indicator on the display 10 lights up, which indicates the good condition of the medium and the possibility of its further storage.

If the P _{claim is} greater than the P _claim , then the red indicator on the display 9 lights up, which means that the information recorded on the controlled medium should be rewritten on a new medium.

Effect: the claimed device provides the ability to control the status of the recording medium and provides objective information about the quality and safety of the recorded program.

The claimed device can be made in the form of a personal computer module or a specialized program adapted to the computer operating system, and can be used both for periodic monitoring of the state of long-term storage media and for current quality control of media used to record information in the consumer and professional fields (radio , television, etc.). If it is necessary to control a large number of disks stored under the same conditions (archival storage, professional work), there is no need to monitor the condition of each disk separately - it is enough to periodically randomly check several samples from one batch of the same manufacturer.

Claims (1)

The device for monitoring the state of a long-term digital storage medium, which contains a series-connected preliminary circuit for processing the read signal, a demodulator, a deinterleaver, a syndrome calculator and a syndrome analyzer, a drive counter, also includes a block for calculating the probability of distorted characters, an analysis result display unit, a time interval setting unit analysis, the unit for setting the admissible probability of the appearance of distorted characters, while the outputs of the unit for setting the time interval with the signals “0”, “start” and “stop” are connected to the inputs of the drive counter, the output of the drive counter is connected to one input of the probability calculation unit, and the output of the time interval setting unit with a signal of the total number of characters read in is connected to its other input during the analysis time, the output of the probability calculation unit is connected to one input of the analysis result display unit, and the output of the setting unit for the admissible probability of the appearance of distorted characters is connected to its other input.