How to recover files from cd. Recovering damaged CDs and DVDs at home

In this article, I briefly described the steps that can help recover data in the most common cases of loss on CD and DVD disks.

So, suppose you burned photographs from your summer vacation in the Maldives on a DVD disc, put it on the shelf and after half a year \ a year decided to refresh your memory of this wonderful event by reviewing the pictures with your friends. You insert the disc into the DVD-rum, the light blinks, the disc gains and decelerates, but you cannot open its contents in the explorer. Or the content is visible, but the required files cannot be copied.

What could have led to such a situation, and what options are possible?

Option zero, nothing to do with the media

It could be the drive itself, the operating system, or viruses. DVD drives differ in optical quality and correction algorithms capabilities. In addition, dust and dirt could accumulate on the lens and prevent the disc from being read. Different drives may differ in the range of supported rotation speeds, and the lower the rotation speed the drive is able to create when trying to read the TOC of a disc (the table of contents of the disc recorded in the Lead-in area), the root directory and the data area, the higher the probability of successful correction of media read errors. ...

Therefore, the first thing to try with an unreadable or poorly readable CD or DVD disc is to try to read it on another accessible computer or laptop. For the purity of the experiment, it is better not on one. There is a nonzero chance that a disc that refused to be read on your computer will be recognized and read on another.

You can also try special utilities that take over the function of determining the rotational speed of the disc in the drive. It happens that the standard firmware does not quite correctly cope with this and manual speed control can improve unstable or poor disk reading. Moreover, the lowest rotation speed will not always be the best for reading - here you need to experiment with the values. In each case, the approach to choosing the optimal reading speed may differ. The most common and easy-to-use utility for this purpose is CDSlow.

CDSlow program window

Option one, it is also the most common, surface contamination

Dirt, dust and fingerprints on the surface of the disc are easy to deal with. We carefully remove dirt with a special damp cloth for cleaning office equipment, taking care not to scratch the coating. Then we carefully wipe the disc with a dry cloth and you can insert it into the drive and try to read.

Wipe from the center to the edge, not in a circular motion. If a grain of sand gets under the napkin and scratches the disc, a radial scratch will do much less damage than a concentric one.

Do not use acetone, nail polish thinner, kerosene, gasoline, or other petroleum-based solvents. If you need to use some kind of solvent to remove dirt from the disc, it is best to use alcohol-based solvents.

Option two, scratches

This also includes various forms of thermal damage.

Two ways to classify scratches come to mind:

1. By the integrity of the reflective layer:
   1. The scratch did not affect the reflective coating, only the polycarbonate backing was damaged.
   2. The reflective coating is damaged.
   type = "a">
2. By width and position:
   1. Narrow scratches. Due to the redundancy of stored information, and the use of various corrective algorithms by the drive, they are not very dangerous.
   2. Wide scratches. In addition to the larger amount of corrupted data, additional problems are added, for example, the drive in this place can "lose" a track and continue to read the next one. Successful reading in such cases largely depends on the perfection of the drive.
   3. Concentric scratches are the worst type of damage. Moreover, corrective algorithms no longer help in this case, tk. the entire sector is damaged, along with redundant information, so they still confuse the positioning system.
   type = "a">

Particularly severe damage is clearly visible in the light of the CD, as in this picture:

Scratches on the polycarbonate cover prevent the drive's laser beam from reading data from the working surface, as they distort the focus. As a result, the laser beam either hits the wrong place, or after reflection does not return to the reading element of the head.

Such damage can be repaired by polishing.

There are different ways to polish. Starting from filling scratches with special pastes with a refractive index close to that of polycarbonate, and ending with removing or smoothing the damaged top layer by heating. The methods used for polishing lenses and other optics are quite applicable.

You can polish by hand, or use homemade polishers based on a linear electric razor, or use the specialized tools that are offered in a variety on e-bay.

Successful implementation of the above activities, in addition to the availability of special tools and materials, requires considerable experience. Therefore, if the information on the problematic medium is important for you, I advise you to entrust this work to data recovery specialists. Or use the tips below, limiting yourself to wiping the disc.

On the Internet, you can find descriptions of various "shamanic" methods, such as boiling a blank, freezing it, warming it over gas burner or an incandescent lamp. All methods are designed to melt polycarbonate so that scratches are smoothed out or eliminated. Since these techniques have a high risk of having a destructive, irreversible effect on the host, I do not recommend them.

So, if after fighting scratches using the methods available to you, the data is still not readable, go to

Option three, a crack in the disc

Cracks are of two types - going from the center of the disc to the edge, and vice versa, from the edges to the center. Cracks from the center are formed from microdamages arising on the inner radius of the disc during careless handling or due to defects in the ingots, and then transform into cracks at high rotation speeds. Edge cracks are usually caused by rough handling but are exacerbated, especially on poorly balanced discs.

To recover data from a damaged media in this way, first of all, it is necessary to take measures to prevent crack growth, which can lead to irreversible data loss and even rupture of the disk in the drive. As a minimum, you should reduce the rotational speed of the disk to the minimum.

Methods to counteract crack enlargement are similar to those used in auto glass repair. First, the crack needs to be drilled. It is best to use a thin needle heated over a fire for this purpose. Using a magnifying glass, make out the end of the crack and make a puncture in the plastic a fraction of a millimeter further. It is best to do this not from one side, piercing the disc through and through, but from both sides, inserting the needle into the plastic about half the thickness of the disc.

After that, it is advisable to glue the crack along the maximum length. To do this, you can slightly spread the edges of the crack, gently coat with a thin layer of superglue, in a minimum amount, so that there is no excess on the surface. Then bring the edges together and press them together. Make sure that the seam surface is even, without protrusions that could damage the optics of the drive.

Further steps are similar to working with scratched discs - if unreadable,

Option four, damage to the substrate due to the low quality of the media selected for storing information or non-compliance with the storage conditions for a DVD or CD disc

According to GOST R 7.0.2-2006 for the preservation of documents on compact discs, each disc must be stored in a separate box at a temperature of 10-20 degrees Celsius, a humidity of 20-65% and in diffused light without ultraviolet radiation. If you believe this normative document, then, adhering to the above rules, CDs will live happily ever after. However, the choice of the blank as the future carrier of your important data is of no less importance. Many reviews have been written on this topic. I just want to highlight the most important points.

High-quality discs from the ends must be varnished, in contrast to their low-quality counterparts. If the end of the CD is not varnished, over time, moisture will enter between the polycarbonate coating and the substrate, which will lead to oxidation of the layer that carries information, and data in such damaged places will be irretrievably lost.

The same effect can occur if the protective cover of the CD or DVD disc has been seriously damaged. The atmospheric moisture that gets on the substrate will corrode everything around the damaged area in the same way.

Methods and approaches to data recovery in case of such damage are also not original, the same

Option five, write failure or unsuccessful attempt to add to RW disk

In this case, problems with reading user data are logical. It is difficult to give general recommendations, because failures caused by errors in software or user actions lead to a wide variety of consequences. The most common method is to trick the drive's microprocessor.

If the error is related to attempts to add a session to a multisession medium or to an error in recording the current session, then you can try to access previous sessions using a program that can display a list of previous sessions and extract the contents of the selected disc session and write it to an ISO image. This feature is also available in the "folk" Nero Burning Rom and in many other DVD burner managers, for example, in the Roxio Easy CD DVD Creator.

Option six, rewritable disc erased or overwritten

If a so-called quick erase was performed, an analogue of quick formatting on a hard disk, when only the TOC - disk file system is deleted, then the data can be restored. Needed with

If Quick Erase has been applied to the disc and then a portion of the top has been written new information, then you can restore only what has not been overwritten. We take a full dump of all available maximum capacity, then cut off the excess and carry out recovery according to the specified file headers in the rest of the section.

If a full erase has been applied to the disk, then data recovery is not possible. In this case, a high-power laser pulse passed over the entire surface of the disk and heated the amorphous substance (recording material) to a temperature lower than the melting point, but higher than the crystallization temperature. The change of amorphous and crystalline areas, which were recognized by the drive as logical 0 and 1, disappeared. The entire layer, after complete erasure, crystallizes and is ready for rewriting.

The last option, nothing is recorded on the disc at all

Oddly enough, data recovery specialists encounter such a situation quite regularly. For example, many users, especially inexperienced ones, use not specialized software to write information to DVD or CD disks, but the means of the operating system (read Windows). Select the required files and folders with the mouse, right click they select the item to send to the drive, see the window on which the files "fly" to their destination and calm down on this. In fact, after such an operation, the files are copied not to the disk, but to a special temporary folder, and after this operation, you need to call an additional Windows wizard, which will conduct the last stage during which, in fact, the recording will take place on the media.

These are, perhaps, all the most common options for data loss on CD and DVD disks that users face. In conclusion, I would like to once again advise the following - if the lost information is of high value, leave the experiments until better times, entrust data recovery to professionals.

Application zero. Copy and reconstruction techniques

The following options are possible:

1. The damage allows the drive to read the TOC and the directory tree (the contents of the disc are visible), but the necessary folders and files cannot be read. To copy them, you can use programs that allow you to read the disc sector by sector, ignoring or intelligently handling read errors uncorrected by the drive. The most useful and programs are described in the respective appendices.
2. The drive is detected by the drive, but an attempt to view the contents by means of the OS leads to a freeze or an error message. I am not aware of free programs that allow you to efficiently recover data in such situations, so refer to the use
3. The disc is not recognized by the drive. The drive tries to read the disc at different speeds, the activity indicator flashes, after a row unsuccessful attempts read the table of contents at different speeds, the spindle stops. A preliminary making of a sector-by-sector copy is required on a drive specially prepared for this. Then we analyze the resulting image

Application one. Hot swap

If the damage is such that the TOC cannot be read and the drive is not recognized by the drive, it is necessary to resort to the hot-swap procedure of the disk, the so-called "hot-swap" method. The thing is that the drive really needs only three main TOC fields: the address of the output area of ​​the disk (analogue of MAX LBA on the HDD), the starting address of the first track (0 LBA) and the address of the next session of the disk (if a multisession disk was recorded). The starting address for all disks is the same - 00:02:00 (which corresponds to a zero LBA address). Lead-Out depends on the size of the disc (typical CD approximately 700 Mb, typical DVD 4.4 Gb).

The trick is that you take a blank disc of the same type and size, CD or DVD, and write one file to it for the entire logical size - either a movie, or an image file (unpacked), or some kind of archive. Further, the case is prepared in a special way, the case is disassembled or the eject signal, the drive is blocked.

To hot swap a CD in the drive, you must use the same donor disc type as the unreadable one. Those. If you need to recover information from a DVD-RW disc, then to prepare a donor disc, whose TOC will be recorded in the drive's RAM, you need to take a similar DVD-RW disc. If the disc is DVD + R, then the disc should not be "minus" or "RW", but "plus". The same applies to mini-disks, it is better not to use a full-size disk for hot-swap.

The front panel is removed from the drive selected for hot-swap operation, the screws holding the top cover are unscrewed. In general, all conditions are prepared for replacing a disc without pulling out the tray. You need to understand that if your drive is under warranty, then after this procedure the warranty conditions will be violated.

Hot-swappable compact drive

Hot swapping a disk in a drive

In the picture, the top cover of the drive contains a plastic clamping ring with a magnet, which must necessarily fix the CD in the reader. Therefore, after replacing the media with the required one, the cover must be returned to its place.

We insert a new disc with the recorded file for the entire volume into the drive, wait until the disc is recognized and the TOC is read and placed in the cache, after which we either wait for the disc to time out, or spin down programmatically and change the new disc to an unreadable one. Now you can start and subtract all the available LBA into the dump. Then we parse the contents of the dump using the same programs. With a large number of errors, the process can take quite a long time.

Some specialists, to recover data from disks with TOC problems, use drives with modified firmware, which allows you to bypass TOC initialization and get direct access to the user area. In addition, it uses its own software, which allows you to change the direction of reading (from the beginning of the disk, from the end, from any LBA) and intelligently handle situations with a read error (repetitions of reading, skipping specified areas, etc.), which can significantly improve the results of recovering information from disks, containing multiple read errors.

Appendix two. Commercial software for recovering data from DVD, CD disks

How to use ISOBuster

- a popular and rich in affordable utility for working with disk images and recovering information on CD / DVD media. The program allows you to view and extract files, tracks and sessions from CD-i, CD-Text, VCD, SVCD, CD-ROM, CD-ROM XA, DVD and DVCD discs.

ISOBuster supports ISO9660, Joliet, Romeo, Little Endian and Big Endian byte order, all kinds of UDF (UDF 2.01 / UDF 1.02, UDF 1.5), Rock Ridge (Commodore), short and long filenames. To recover data from damaged media, the program has a valuable option - the ability to re-read damaged sectors multiple times, which increases the chance to correctly subtract one or another problem sector.

The start window consists of two panels - on the left is the window for selecting images, sessions, disks and folders, and on the right is the explorer. After launching the program, the left panel will display the tracks and sessions that the utility was able to recognize, and the right panel will display the files and directories found as a result of a quick pre-scan. If necessary, you can run an extended scan, the so-called. "Search for skipped files and folders".

Data recovery can be performed for the entire disk as a whole, or for individual folders and files. To do this, select what you want to read from the damaged media and use the "Eject" command.

If during copying a bad sector is found on the media, the user is presented with a window asking him to try to read this sector again or skip it. Rereading a bad sector is sometimes successful and its contents are read successfully.

When you start and finish scanning the contents of optical drives, the program displays in a drop-down menu all available sessions that were recorded on the disc. If there was a failure in one of the last sessions, ISO Buster allows you to work with a separately selected session and extract its contents as a RAW data array (in the form of an image for subsequent parsing by headers), or work with the selected session in explorer mode.

ISO Buster allows you to generate a variety of reports on the directory tree, including taking into account unreadable content (data containing unread sectors).

If you are working with a disk using the hot-swap method, when the TOC in the drive memory does not correspond to the original, you can set the copying of the range from the selected LBA to the selected one.

At the stage of reading data into an image file, you can specify the use of intelligent filtering if the type of data on the recovered medium (Video CD, Audio CD) is known in advance. In this case, ISOBuster will filter out sectors that match the selected criteria.

Further parsing of the image file and data recovery from it is carried out in the same way as working with a regular damaged CD. To do this, you must first open the image file File-> open the image file.

How to use WinHex

- a popular multifunctional program for working with various media. It can work with CDs both at the logical (in the understanding of the OS) and at the physical (in the same sense) level.

WinHEX program window

Vinhex can remove a sector-by-sector image from a damaged disk, save the resulting dump to a file, and then parse it into components or use the data recovery function by file signatures. Unlike hard disks, CD and DVD media do not contain fragmentation, which makes such recovery methods much more difficult.

Through the menu item Tools-> Open Disk, the user gets to a window with options for choosing a physical or logical disk for work. If the drive did not recognize the presence of a disk in the tray (before the operation on), then when you try to access the item in the list of logical disks, an error message “device is not ready” will be displayed,

and when you try to access a physical disk, the program will display an error message “no access to the device”.

After correctly performed, access to the LBA disk becomes available and you can go to the sector-by-sector copying operation: Tools-> Disk Tools-> Clone Disk. Here options are available for cloning to a separate media or to a file of the entire available surface or some area, selection of the starting sector for the source disk and for the target disk (if copying is not performed to a file), selection of a placeholder pattern for unread sectors and the size of the jump when unread is detected. sectors (if you want to speed up copying on a disk with numerous uncorrectable read errors).

In our case, you need to select copying to a file and specify the path where to save it. We set zero as the initial sector, indicate some other number, it makes sense only if we can assume the number of unreadable sectors at the beginning of the disk. After putting all the necessary marks, you can start copying. The program saves the report on unread sectors to a separate log file.

It is now necessary to restore the necessary data from the image obtained after subtracting. To do this, you will have to use the so-called RAW Recovery function or recovery by file signatures. What does it mean? The vast majority of file types have unique character sequences, the so-called. signatures that can be used to uniquely determine the file type. As a rule, it is convenient to take several characters at the beginning of the file as a signature. By specifying the required signature as a selection criterion, you can restore all files of one type or another (extensions) from the resulting image.

File header using a JPEG example

In the search process, the following algorithm is used: the software finds the selected file header and saves the entire data array until the next found similar header, assuming that it is a single file, or the data array of the volume specified in the settings is saved from the found header (you can specify "with a margin") ...

Of course, in this case the file names and directory structure will not be saved, but it is better to get the data in this form than not to get it at all. The main problem that can arise when recovering information using the RAW recovery method is fragmented data, when part of the file is located in one place, and the other part (s) - in another. But in the case of recovering files from an image that was read from a CD / DVD, this does not happen, since the data is written linearly.

File recovery by headers in WinHex is available from the Tools-> Disk Tools-> File recovery by type menu. First, open the resulting image File-> Open, select "recovery by file type". The program displays a window with a reminder that the data needs to be saved not where everything is being restored from, but in another place (if you are working with an image file, you do not need to worry about this) and reminds you that this option will give good results for unfragmented data.

The signature recovery settings window offers to select the type of files that you plan to extract from the image, the maximum estimated file size, the directory to save everything to, and the search algorithm: Extensive byte-level search (the slowest and most advanced, I recommend using it), Search at sector boundaries and Search at cluster boundaries, if possible.

If the disk contains files of rare types that are not described in the "Select file type (s)" reference, then by clicking on the Signatures button, you launch the system spreadsheet editor (such as Microsoft Excel), in which you can manually add the required header.

After all the manipulations done, all that remains is to click on the "Ok" button and wait for the result. All files that meet the specified conditions will be saved to the selected directory.

Appendix three. Free software to recover data from DVD, CD disks

- the most functional, from my point of view, of free programs. It is positioned as software that can also work with flash drives and hard drives. During the installation process, it installs its own libraries into the system, which help the program to better handle emergency situations with problematic storage media. A system reboot is required after installation.

The program window is divided into two parts: where to copy (top) and where to copy (bottom). To start copying, you need to drag the files from above with the mouse, or go to the folder that you want to copy completely and click "Copy". The copying algorithm can be configured by selecting the "Settings" sub-item of the "View" main menu. I will not dwell on the configuration issues in more detail, since the program contains quite detailed reference information.

I would also like to draw your attention to the fact that the utility has an EXTRA mode, which should start automatically when errors in reading CD or DVD discs are detected.

Recovery Toolbox for CD Free

Recovery Toolbox for CD Free- a utility from a well-known company Recovery Toolbox, which specializes in creating utilities for recovering data from corrupted files of various types, from doc and xls to registry files and exotic databases. The only free program mentioned here that does not have a Russian interface. The copying algorithm is not configurable.

When starting the program, you are prompted to select the drive from which the restoration will be performed, as well as the path where you want to save the subtracted. After reading the TOC, the utility offers to mark the necessary directories and files, and the saving process begins. If unreadable sectors are encountered during copying, the user is prompted to re-read or skip the sector (file). At the end of the process, you can save a report on the work performed.

DeadDiscDoctor

DeadDiscDoctor- has a minimalistic interface with beautiful pictures. Uses the original copy algorithm, the settings of which cannot be changed. Choose what to copy, choose where to copy, start the process.

Non-Stop Copy

Non-Stop Copy- the interface is similar to DeadDiscDoctor. The downside is that there is no way to choose to copy more than one file at a time. There are minimal algorithm settings.

Reprinting or quoting is permitted provided you keep a direct link of data recovery from DVD CD to our website.

Many people prefer to save important information for themselves (photos, work files and other documents) on DVD-disks. As such, they do not have a shelf life, but, nevertheless, due to any mechanical damage, they fail. The reasons can be the most commonplace:

the formation of scratches;physical deterioration;poor quality of the material from which the disc was made.

Reading and copying information in such cases turns out to be impossible, but there are methods and programs that will help to cope with this problem.

Two main types should be distinguished possible problems: logical malfunctions and surface damage, as a result of which, the damaged DVD finally stops working, if the damage is really large-scale, then it is quite difficult to do anything.

Logical faults

This method is implemented with the support of specific software, not only in manual, but also in an automated mode.

In the process of using the software, the entire information layer contained on the carrier is first scanned. As a result of scanning, on the basis of the detected service information, a so-called "map" of information location is formed. The "map" contains information about which cluster belongs to which file or directory, dimensions, names and all other characteristics of the elements of the scanned file system.

After that, the information is restored - the selected data is transferred to another medium. Writing to the original medium is not carried out when restoring information.

Surface restoration

Before using any software, it is advisable:

restore the damaged surface as much as possible;

after polishing to neutralize scratches on standard or specific equipment, a full copy is made.

Then, depending on the state of the final copy and the method of obtaining it (for example, it may be necessary to pre-decode), the entire sample is sampled. necessary information directly.

Special programs

The utilities available today, using special mechanisms for reading information, are ultimately able to either read files or copy them (although they cannot guarantee an absolute recovery of each of them). These programs have the ability to read information from disks of any format, using direct access and bypassing the standard, ineffective in this case, tools that are typical of the Windows system.

They make many attempts to read the "bad" segment of the disk, and at the same time are able to continue reading or copying data after errors in the process of reading. This often makes it possible to "pull" information in its primary form. In the event that such a method does not work, then the overwhelming majority of the presented utilities are simply able to replace the "non-working" sections with zeros. Of course, in this place in the document, as a result, some kind of defect is formed. Among the utilities capable of recovering a DVD disc should be designated:

CDCheck;

BadCopy Pro;

IsoBuster;

Recovery ToolBox.

The latter of them performs a full scan of failed disks and backs up the maximum possible amount of data. While performing recovery, Recovery Toolbox uses a significant number of various operations, and this greatly increases not only the quantity, but also the quality of the information being recovered. Thus, it will be indispensable in situations such as:

damage to the physical plane carrier (namely, scratches, contact with liquids);

changing the disk format using data recording utilities;

operating system error while reading and accessing the media.

Some of the categories of files should have their peculiarity taken into account. For example, if we talk about a video file, then the program should be able to correctly restore the index of this file, while noting its damaged parts. This is done so that the player can later play this video file, and the lost frames are painted with a certain shade.

In addition, different programs also have different recovery processes, and therefore, if it turned out to be impossible to recover something in one application, then, most likely, it will work using another.

other methods

If the disk is not too badly damaged, you can try a method such as reducing the read speed of the drive. This can be effective, because at high speed the PC may simply not perceive the information that was not damaged. You can also consider a damaged disk in various drives from all kinds of manufacturers, each of which, respectively, has its own speed.

For minimal damage, a special polishing gel can also help to restore the finish. It is advisable to do all this with a microfiber cloth.

Some of the drives use hardware methods to increase the efficiency of reading data not only from CDs, but also from DVDs that have been damaged. The list of these funds may include:

modified focusing of a laser-type diode;

disc ellipsoid compensation and much more.

If such hardware is available in the drive, in such a case, you can try to use it using the drivers or the software that was delivered with the drive.

Thus, there are methods for recovering and reading information from DVDs, but one or another of them turns out to be more or less effective, depending on the degree of damage to the file and on what kind of information was stored on it.

There are a great many reasons for damage to information. However, regardless of the degree of damage to the mirror surface, there is almost always a way to salvage the data. You can do it different ways... There are specialized applications that make it possible to reanimate information even from practically unreadable discs.

Causes of damage to discs

Most often, the following situations arise:

• there are problems with the drive;
• the CD has a lot of scratches;
• cracks;
• the substrate is damaged;
• there was a failure during recording;
• RW sterly blank for subsequent rewriting on it.

Photo: percentage of data loss

In each of the above cases, the content can be salvaged in different ways. The easiest way is to use programs for recovering data from CDs and DVDs. There are also various mechanical methods - directly affecting an unreadable surface.

Drive problems

Often the problem is not with the CD, but with the drive.

There are many reasons for this situation:

• poor quality of the optics used in the device;
• the correcting algorithm is not powerful enough;
• There are dust particles or other foreign objects on the focusing lens.

To test the devices for working with the media in question, you just need to try reading the drive on a different drive. If this succeeds, then it is the device that is to blame. Otherwise, the reason lies directly in the disc itself. This situation can be resolved by lowering the spindle speed - the lower it is, the higher the probability of successful reading.

Surface contamination

One of the most common causes of reading problems is surface contamination. Most often there are fingerprints or the most common dust. It is quite easy to deal with this kind of pollution. It is enough to gently wipe the surface with special napkins for cleaning office equipment, then repeat the process with a dry cloth.

It is very important to wipe not in a circular motion, along the paths, but from the center of the drive to its edge. Since the scratches are radial, which can be caused when a grain of sand or other object hits the surface of the rag, they will do much less damage than concentric ones.

In no case should you use the following substances to remove dirt:

• acetone;
• solvent for nail polish;
• petrol;
• kerosene.

The substances listed above can damage the material from which the CD / DVD is made.

Scratches

Gaining access to information is greatly hampered by various types of mechanical damage. First of all, these are the most common scratches. The polished surface is quite fragile, so it can be damaged very easily - one grain of sand is enough.

Mechanical damage can be classified according to their shape and location:

• narrow;
• wide;
• concentric.

Narrow scratches usually do not pose a serious hazard due to the large number of corrective algorithms available. Wide scratches are more dangerous - the device for reading can simply lose track, while starting to read the next one.

Concentric scratches are the most problematic. Since they usually damage the whole sector of information. Most corrective algorithms are unable to cope with this type of problem because the positioning system cannot operate normally. Only surface polishing can resolve this situation.

Cracks

Cracks are another big problem.

They are of two types:

• from the center;
• from the edge.

With frequent use of the drive at high speeds, defects of this type are only exacerbated. The situation can be corrected with the help of mechanical repair and special software for information resuscitation.

Damage to the substrate

Damage to the substrate is often the cause of problems.

Photo: damage to the substrate when hit

Defects of this type occur in the following cases:

• storage conditions are not met;
• the blanks are of poor quality.

Most often, the substrate is damaged due to the ingress of liquid between it and the polycarbonate. This usually happens due to the lack of varnish on the ends, or when the drive is stored in a room with high humidity.

Failed to write

Sometimes the CD / DVD is already damaged during recording. This usually happens due to a software error, or any incorrect actions by the user himself.

The easiest way to access information is in the following cases:

• additional recording was performed on a multisession RW-type medium;
• an error was made during the execution of the current session.

Recovering data from a CD in such cases is usually straightforward. It is enough to use specialized software.

Rewritable disc erased or rewritten

Sometimes it is necessary to return information lost during erasure or rewriting.

Such processes can be divided into the following types:

• quick erase;
• complete erasure.

When using quick erase, you can partially reanimate the data. If the full is applied, then the data is lost forever.

Video: Repair CD DVD with Scratches

Disk recovery methods

At the moment, all resuscitation methods can be divided into the following categories:

• software;
• hardware;
• mechanical.

Program

There is a large selection of different software for resuscitation of damaged media. Software of this type simply fills in unreadable content with empty bits, or makes copies from neighboring areas. This method is not suitable for all file types.

Each application is quite effective in recovering access to lost content. But this method does not always help - in such a situation, it is advisable to resort to a hardware or mechanical data recovery method.

Hardware

To carry out hardware resuscitation of the drive, utilities are used with built-in specialized drivers. They make it possible to use cluster reading - this way you can avoid freezing the operating system while working with a damaged disc. Thanks to this type of reading, you can minimize the loss of information.

Some readers have built-in functions:

• improved focusing of the laser beam;
• ellipsoid compensation.

Mechanical

If the defects on the surface are very extensive, then mechanical restoration - polishing can be applied. To carry out this operation, special equipment is required, as well as extensive experience. Also, all kinds of scratches are repaired in the same way as cracks on the glass of cars - drilling is performed, after which the edges are glued together with polymer.

Copy and reconstruction techniques

The copy and reconstruction method can be applied in the following cases:

• it is possible to read the TOC, the directory tree - but there is no access to the required files and individual folders;
• when trying to read the drive, the OS hangs;
• the reader tries to access the data at different speeds, but there is no positive result.

If it is impossible to get access to the TOC, you can apply sector-by-sector reading or intelligent processing. If the medium is not recognized, then it is advisable to make an image of it and then reconstruct the damaged areas using special software.

TOC is not readable, we do hot swap

If the TOC cannot be read and the blank is not recognized by the drive, a hot swap process can be performed.

Only three TOC fields are required for a successful read:

The hot-swap process requires a similar, fully-written disk, and disassembly of the reader.

The hot swap process itself is as follows:

• a new CD / DVD is inserted;
• after reading the TOC, it is replaced with an unreadable one (disassembly of the drive will be required);
• specialized software for reconstruction is launched.

How to recover data from a CD

There is a large number of different software for reanimating drives of this type. It can be either commercial or free. This usually does not affect its reliability.

ISOBuster

To reanimateCD/ DVDwith helpISOBuster, you need to do the following:

• open the utility and select the device in the left part of the window;

• in the right part of the window, call the context menu for the desired object and click on "create an IBP / IBQ image file".

After completing the process, you will need to mount the resulting image to work with it.

To reanimate data usingrequired:

The whole process takes a long time. But upon completion, the user will be able to access the files.

Recovery Toolbox for CD Free

Work with theRecoveryToolboxforCDFreeis carried out as follows:

• after launch, the device selection window will open;

• Recover damaged data from all the most common types of media today
• Working with data that has become spoiled both after physical damage to the media, and as a result of software errors
• Giving the user complete control over the recovery process
• Providing the user with the most detailed report on the data recovery process

Most importantly, all of these brilliant user experiences are completely free! From now on you have an affordable, uncomplicated yet powerful data recovery tool at no cost!

Data recovery utility from damaged media

Utility Recovery Toolbox for CD Free designed to recover data from damaged media of all the most common types of media today: CD, DVD, HD-DVD, Blu-ray, etc. The program allows you to recover files of any type. The utility performs a full scan of damaged disks and retains as much information as possible. In the process of recovery Recovery Toolbox for CD Free applies a large number of different algorithms, which significantly increases the quantity and quality of recovered data.

The user will receive a complete, easy-to-read report of all the details of the recovery process.

The program provides the user with extremely convenient options for complete recovery control: where and which files to recover, to which folder and where to save the data, etc. It is also available to view all the necessary information, both about the source of the recovered data, and about the place where it was saved.

The utility will be indispensable in the following cases:

• physical damage to the media (scratches, contact with liquids, etc.)
• damaged media format by disc burning programs
• OS errors when reading and accessing the media
• etc. etc.

In all these unpleasant situations, the program will quickly and efficiently perform all the necessary actions to recover as much data as possible.

Convenient, intuitive interface makes the process of working with the program efficient and enjoyable.

By the number and quality of algorithms used in the program, ease and accessibility of use, wide functionality, the utility Recovery Toolbox for CD Free- one of the best in its class; and, I repeat, unlike most of its counterparts, it is absolutely free.

Requirements:

• Windows 98 / Me / 2000 / XP / Vista / 7/8/10 or Windows Server 2003/2008/2012/2016 and up

All optical discs (DVD-RW, CD-RW, DVD-R, CD-R) are not particularly reliable, as they often fail. The reasons for this phenomenon can be mechanical damage, viruses, etc. You will hardly be able to copy data from damaged media using standard Windows OS tools. But this does not mean that important files and folders are lost forever, because there are many programs designed specifically to read information from defective discs. Consider the procedure for recovering data from optical disks unreadable by the operating system.

Ways to recover DVD and CD discs

If it is impossible to extract data from a DVD (CD) disc, the first step is to make sure that it is the disc that is out of order, not the drive. To do this, insert another (working) disc into the DVD-ROM and repeat the reading procedure again. If reading starts, then the problem really lies in the storage medium.

Recovery of CDs and DVDs is a complex procedure, during which the following resuscitation methods can be used:

• program;
• hardware;
• mechanical.

The first option for data recovery is considered the easiest to perform, so it is with him that you should start. renovation work... It relies on the use of special programs that allow you to retrieve files from the damaged disk.

Optical disc recovery software

If operating system in the process of copying information from DVD-R / RW, it encounters some kind of failure, then it not only stops this procedure, but also discards the part of the document that was successfully read. Special software for recovering data from failed disks works according to a different principle: if it is impossible to copy a certain sector, the program simply skips it and jumps to the next one. This allows you to recover the maximum amount of lost files.

All programs for reanimating data from failed disks can be conditionally divided into two classes:

• speed limiters;
• utilities for copying information.

The first class includes programs whose work is based on a forced reduction in the rotation speed of a disc in a DVD drive. This allows you to remove files even from those sectors that were inaccessible at high speeds. The second group includes software equipped with a more efficient data reading algorithm than the operating system itself.

The most effective tools for recovering files from unreadable CDs and DVD-R / RWs include:

• CDSlow;
• CDCheck;
• BadCopy.

Using the CDSlow utility

CDSlow is a program that allows you to limit the speed of a DVD drive down to the minimum allowed value for the given device. To recover damaged data you will need:

If even at the lowest speeds when copying data you have failed, move on to the next program.

Data recovery via CDCheck

CDCheck is free program for diagnostics and reanimation of not only optical disks, but also other storage media (USB flash drives, memory cards for mobile devices, ZIP drives, etc.). To recover a disk using this application, you need:

After the end of the program, detailed statistics will be displayed, in which you can see the total time of information processing, the number of errors detected during reading, the average speed of data recovery, etc.

To increase the likelihood of successfully copying damaged files, it is recommended to limit the drive speed using CDSlow or another program before starting recovery.

Reanimating a disk with BadCopy

This program allows you to recover not only damaged, but also deleted files from rewritable media.

Hardware and mechanical methods of disk recovery

If using the program to reanimate the disk did not work, then you can try to restore the hardware method. For this, high-quality DVD drives are used, which have improved focusing of the laser beam and the ability to work at low speeds. Such devices are not cheap, so they are rarely found in private use.