Is it possible to fix bad sectors on hdd. How to recover bad sectors on a hard drive? Recovering bad HDD sectors with Victoria

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Even on the highest quality and most reliable HDD, some time after installation in the PC, broken sectors begin to appear. When the number of bad blocks becomes large, the hard drive stops working and needs to be replaced. However, the hard drive can often be restored using third-party software. This article will describe programs for treating a hard drive and provide instructions for working with them.

Broken sectors

HDD records user information on magnetic disks. Their surface is divided into paths and sectors. If you cannot extract data from a sector, then it is called bad or bad. Although it is difficult to restore bad blocks, it is quite possible.

Remember that after disinfection, the information from the HDD should be rewritten to another drive, and eventually the hard drive should be replaced. If bad sectors began to appear on the hard drive, then after the repair, their distribution will not stop. Another device failure can happen at any time.

VictoriaHDD

VictoriaHDD is a program for treating hard disk sectors, considered one of the most effective and absolutely free. The application works in DOS mode, therefore it requires some preparatory actions. First you should

Download the VictoriaHDD ISO image.
Also download the WinSetupFromUSB application and run it.
In the drop-down menu, select the USB drive that will later become bootable.
Check the box next to "Autoformat".
Check the box "Linux ISO" and show the full path to the VictoriaHDD program image.
Click on the "Go" button to start the file burning process.

BIOS settings

Since the programs for treating the hard drive run in DOS mode, you need to configure the BIOS.

Reboot your computer.
After turning on, press the DEL or F8 button several times to enter the Setup BIOS utility. Some devices have different keys assigned to launch BIOS settings. To find out which one is responsible for entering the "Setup BIOS" on your computer, read the information at the bottom of the screen immediately after turning on the machine.
Go to the "Main" section and find the "SATA Mode" item. Press "ENTER" and select "IDE".
Set the First Boot Device to USB.
Press the "F10" key to save the changes to the settings.
The computer will then restart.

Checking and restoring

If all of the above steps are performed correctly, after restarting the PC, VictoriaHDD will start automatically. To start hard drive recovery:

Press the "P" key on your keyboard.
In the menu that opens, select the port to which the HDD is connected. Today almost all drives work via the SATA socket, so you need to set the switch to the Ext PCI ATA / SATA position.
Press "F9", the screen will display information taken from the SMART table. Pay particular attention to the "Current pending sectors" column. It is here that the number of sectors is indicated, data from which are not read. Remember or write down this number.
Press the "F4" key and start scanning in the "BB: Erase 256" mode. The utility will try to find all bad blocks and restore them. In this case, the information stored in them will be deleted.
Reopen the SMART table and look at the number of bad sectors. If some of them could not be restored, it is worth scanning the HDD in a different mode.
Press the "F4" button and select "BB: Classic Remap". Now the application, when it finds a bad sector, will not restore it, but will mark it as non-working. This approach will stop the spread of bad blocks.
When VictoriaHDD finishes checking, restart your PC.

Programs for treatment tools built into the OS

After scanning the drive with the VictoriaHDD utility, it is worth checking with the utility installed in the operating system by default.

Open My Computer.
Right click on the local disk icon.
Go to the "Service" tab.
Select Check Now.
In the window that opens, check the box next to the "Automatically fix errors".
Click on the "Start" button and wait for the program to finish.
Never turn off your PC until the verification process is complete.

HDD Regenerator

HDD Regenerator is a free program for treatment. The main advantages of the utility are its user-friendly interface. Many users choose HDD Regenerator for this very reason.

Close all applications and launch HDD Regenerator.
Open the "Recovery" menu and click on the inscription "Start processing".
If a window appears on the screen with a warning about the BIOS settings, click on the "No" button.
Select the drive that needs treatment.
After that, a command line will open on the screen, where you will need to enter a number from 1 to 4.
Enter "2" and press "ENTER".
The utility will ask you to indicate where to start scanning. Just press the "Enter" button.
The application will scan the HDD and provide information about the bad blocks.
When the check is completed, enter "2", now the utility will not only check the hard drive, but also try to recover the bad sectors.

I must say that the program for treating the hard drive Windows 7 is very slow. Sometimes the process is delayed for 2-3 days. However, HDD Regenerator is really trying to restore the ability of blocks to store data, and not just mark them as unused, which explains the long scan time.

MHDD

MHDD functionality is almost identical to VictoriaHDD. The application runs in DOS mode. It can be used to view the SMART table, diagnose and disinfect the hard drive. The program is not presented in Russian.

Create a bootable USB stick as you did for the VictoriaHDD utility.
Perform BIOS setup and restart your computer.
Press "F2" and select the device you want to work with.
To scan the surface of the hard drive, enter the word "SCAN" or use F4. The screen will display settings in which all destructive functions are disabled (erasing, removing bad blocks).
Press "F4" again. Scanning will start, and the display will show a table in which the colors of the cells will change during the test: white, gray, green - the sector is operational; yellow - there is a risk of damage; red - the unit is damaged.

If there are bad blocks on the drive:

Copy all information to another HDD.
Enter the ERASE command, which will completely erase data from each sector. This will get rid of the soft-bad blocks.
If this does not solve the problem, press the "F4" key and enable the REMAP option. Now the utility, like the programs built into Windows for treating the hard drive, will simply mark the bad sectors, and they will no longer be used.

The hard drive is a very important component of any computer. At the same time, he is sensitive and susceptible to various problems. So, broken sectors on the surface can lead to a complete failure of work and the inability to use a PC.

It is always easier to prevent a problem from occurring than to deal with its consequences. Therefore, it is important for every user who wants to prevent possible problems associated with incorrect operation of the HDD to monitor the presence of bad sectors.

Sectors are units of storage of information on a hard disk, into which it is divided at the production stage. Over time, some of them can become faulty, inaccessible for writing and reading data. Bad sectors or the so-called bad blocks (from the English bad blocks) are physical and logical.

Where do the broken sectors come from?

Physical bad blocks can appear in the following cases:

Manufacturing defects;
Mechanical damage - falling, ingress of air and dust;
Strong shock or shock while writing / reading data;
Overheating HDD.

Such sectors, alas, cannot be restored; one can only prevent their occurrence.

Logical bad sectors appear due to software errors caused by viruses or a sudden power outage while writing to the hard drive. Every time the HDD is checked before recording, it is not performed in problem areas. At the same time, physically such sectors are completely serviceable, which means that they can be restored.

Signs of bad sectors

Even if the user does not check his hard drive, bad sectors will still make themselves felt:

System freezes, especially when writing and reading data from the hard drive;
Sudden reboots and unstable PC operation;
The operating system generates various errors;
A noticeable decrease in the speed of performing any operations;
Some folders or files won't open;
The disc makes strange sounds (creaking, clicking, tapping, etc.);
The surface of the HDD is warming up.

In fact, there may be more signs, so it is very important to be attentive to the work of the computer.

What to do if broken sectors appear

If bad blocks appear as a result of physical impact, such as dust and debris inside the device, or malfunction of disk elements, then this is very dangerous. In this case, bad sectors not only cannot be corrected, but it is also impossible to prevent their further appearance every time the system accesses data written to the disk. To avoid complete loss of files, the user needs to reduce the use of the hard drive to a minimum, rewrite the data to a new HDD as soon as possible and replace the old one in the system unit with it.

Dealing with logical bad sectors will be much easier. First, you need to test using a special program that will help you find out if such a problem exists on your disk in principle. If it is found, then it remains to start fixing the errors and wait for them to be eliminated.

Method 1: using the utility to diagnose the condition

You can find out if there is a problem with your HDD using specialized software. The program is simple, affordable and free. Its functionality includes complete diagnostics of the hard drive, in the report of which you need to pay attention to 3 points:

Reassigned sectors;
Unstable sectors;
Fatal sector errors.

If the disk status is marked as “ Good”, And blue lights are on next to the above indicators, you do not need to worry.

But the state of the disk is “ Anxiety!" or " Bad»With yellow or red lights signals that you need to take care of creating a backup as soon as possible.

You can also use other utilities to check. In the article at the link below, 3 programs are selected, each of which has a function for checking bad sectors. It is worth choosing a specific utility based on your experience and knowledge for its safe use.

Method 2: using the built-in chkdsk utility

Windows already has a built-in program for checking the disk for bad blocks, which copes with its task no worse than third-party software.

1. A bit of history

Bad sectors (from the English - bad, unusable) are on any hard drives. No matter how carefully their disks were made, each of them contains several places, the writing or reading of which is accompanied by errors. In addition, there are simply glitchy surface areas that can develop into defects over time, which is unacceptable for the user. Therefore, each drive, after being manufactured at the factory, undergoes thorough testing, during which bad sectors are identified. They are marked as unusable and entered into a special table - defect list .

The very first screws had a defect sheet in the form of a paper sticker, into which the addresses of unstable areas were entered at the factory. These devices, which are a slightly modified copy of a conventional floppy drive, could work only under their physical parameters: the number of tracks, sectors and heads indicated in their passport exactly matched their real number. By purchasing such a device, the user read the sticker and entered the addresses of the killed areas in the FAT himself. After that, the operating system stopped noticing these defects, just as it does not notice bad blocks on floppy disks if they were removed by scandisk. Probably, in those distant times, the term "bad block" appeared: a block was called cluster - the minimum unit of logical disk space. At the physical level, the cluster consists of several sectors, and if one sector is damaged, the OS declares the entire cluster unusable. There were no other methods of hiding defects at that time. And when there were ways to hide certain sectors, people did not come up with new concepts, and they still successfully continue to use the word "block".

It wasn't long before the manufacturers came up with a very interesting thing: if the user still marks bad blocks as unnecessary, they reasoned, then why not mark them right at the factory? But how to do this if there is no file system on the screw, and it is not known what it will be? That's when they came up with a tricky thing called "Translator": they began to write a special table on the pancakes, in which it was noted which sectors should be hidden from the user, and which should be left to him. The translator has become a kind of intermediate link connecting the physical system "disks-heads" with the storage interface. It was assumed that when the screw is turned on, it will first read its internal tables, hiding the addresses of defects marked in them, and only then will allow the BIOS, OS and application programs to access it. And so that the user does not accidentally overwrite the translator while working, it was placed in a special area of the disk, inaccessible to conventional programs. Only the propeller controller could access it. This event made a real revolution in the hard drive industry, and marked the emergence of a new generation of drives - with a service area. In order for all screws of the same model, but with a different number of defects, to have the same capacity, they began to leave spare tracks on each of them - a reserve specially provided for equalizing the capacity of the same type of drives to the standard declared value. They began to place it at the end of the disk, near its center, and it was also inaccessible to the user. When leaving the factory, such hard drives did not have more than one visible bad sector. If new defects appeared during operation, the user could make low-level formatting with a universal utility from the motherboard BIOS and try to hide them. Sometimes, as with floppy disks, it succeeded. But if the "evil spirits" were physical, then this did not help: it was impossible to add new defects to the table and rewrite the translator without special programs. Therefore, the bad blocks on many old screws (before 1995) had to be hidden in the same outdated way - through FAT. And only Seagate, Maxtor and Western Digital released utilities for hiding defects and replacing them from the reserve (they are still lying on some ftp files and are called sgatfmt4.exe, mformat2.exe and wddiag.exe, respectively).

Time passed and the screws changed even more. In an effort to increase the recording density, the developers began to use various non-standard tricks: they began to apply servo marks designed for a more accurate hit of the heads on the tracks. The technology of zone-section recording (ZBR) appeared, the meaning of which was a different number of sectors on the outer and inner tracks. The head drive has changed - instead of a stepper motor, they began to use a positioner in the form of a moving coil. And the heads and disks themselves have changed so much that each company has developed its own structure of the lower-level format, sharpened only for their technology. This made it impossible to use universal low-level formatting utilities due to the fact that the translator of such screws learned to hide the physical format of the drives, translating it into a virtual one. The number of cylinders, sectors and heads written on the screw body ceased to correspond to their true values, and attempts to format such a screw with old utilities, as a rule, ended in failure: its controller rejected the standard ATA command 50h, or simply imitated formatting by filling the screw with zeros. This has been specifically left out for compatibility with older programs. For the same reason, the Low-Level Format procedure has been excluded from the BIOS of modern motherboards. And to make these screws really low-level formatting, it was necessary to bypass the translator, gaining direct access to the physical tracks and heads. To do this, they began to use a technological utility that launches a special microcode written in the drive's ROM. The command for calling this microcode is unique for each propeller model, and refers to technology teams which are not disclosed by the firm. Often such formatting could not be done through a standard IDE interface: many models of screws from the 90s - Conner, Teac, etc., as well as all modern Seagates, require a separate connector to be connected to the terminal via a COM port. As for technological utilities, they were never widely distributed and were not available to the average user. For widespread use, foolish programs have been written that carry out pseudo-formatting through the interface: filling the disk with zeros to clear it of information. This can be seen even from the names of these utilities, which can be found on the websites of hard manufacturers: wdclear, fjerase, zerofill, etc. Naturally, there are no technological commands in these programs, and therefore they can be applied to any hard drives. Such utilities are often useful, helping to get rid of some types of BADs, which we will talk about a little later.

Why did the manufacturers act so cruelly, depriving us of the ability to do the right low-level formatting, and hide defects on our own? There is still no consensus on this question, but the official answer of most companies sounds something like this: “This is such a complex and dangerous operation that an ordinary user cannot be allowed to do it, otherwise many screws will simply be killed. Therefore, low-level formatting can only be done at the factory, or in a corporate service center. "

Let's try to figure out if this is really so. And at the same time, let's look at what real low-level formatting of modern hard drives is, is it possible to do it yourself, and most importantly - do we need it?

2. Preparing the hard drive at the factory

Before hiding bad "s at the plant, it is very important to identify everything, even very small defects, as well as unstable areas that can develop into bad" s over time. After all, if this happens during operation, the user may lose an important file, and the reputation of the company that released such an "unfinished" drive will be damaged. Therefore, testing hard drives before hiding defects takes a very long time, at least several hours, and is performed in technological mode. This is done to eliminate time delays that inevitably arise during the operation of the translator, transferring data through the cache and interface logic. Therefore, at the factory, the surface is scanned only by physical parameters. Usually, this is not done by an external program, but by a special module in the ROM of the screw, which works without the participation of the interface. The end result of such testing is getting a defect list - an electronic list of unusable areas of disk space. It is entered into the propeller's service area and stored there throughout the life of the drive.

Modern hard drives have two main defect lists: one is filled at the factory during the manufacture of the drive and is called P-list (-primary), and the second is called G-list (from the word - growing), and is replenished during the operation of the screw, when new defects appear ... In addition, some screws (in particular the Quantum Fireball of the ST and TM series) also have a list of servo defects (servo marks applied to the platters of hard drives also sometimes have errors), and many modern models also contain a list of temporary (pending) defects. In it, the controller enters sectors "suspicious" from its point of view, for example, those that were not read the first time, or with errors.

Having received a defect sheet, they begin to hide the defects. There are several ways to hide them, each of which has its own characteristics. Theoretically, you can simply reassign the addresses of the damaged sectors to the reserve and take them from there, but this will cause a loss in the performance of the screw, since each time it detects a sector marked as unusable, it will be forced to move the heads to the reserve area, which may be far from the place of the defect. If there are a lot of reassigned sectors, the performance of the drive will drop dramatically, since most of the time it will spend on useless twitching of the heads. Moreover, the performance of screws with different numbers of defects will vary greatly, which, of course, is unacceptable in mass production. This method of hiding defects is called "Substitution method" or remap(from English: remap - rebuilding the sector map).

Due to the numerous shortcomings inherent in remap, in the industrial manufacture of screws, this method is never used, but a different algorithm is used: after identifying all defects, the addresses of all serviceable sectors are rewritten so that their numbers go in order. Bad sectors are simply ignored and do not participate in further work. The spare area also remains continuous and part of it is attached to the end of the work area to equalize the volume. This way of hiding bads is more difficult to implement than remap, but the result is worth the effort spent on it - with any number of faulty sectors, the drive does not slow down. This, the second main type of defect concealment is called "Sector skip method"... (There are other algorithms for factory defect hiding, for example, by eliminating an entire track, or using a spare sector on each track, but they have drawbacks and therefore are practically not used in modern drives).

The process of recalculating addresses with skipping defects is called "internal formatting". Internal - because the whole process takes place completely inside the screw, at physical addresses and without the participation of the interface. At this time, the screw is under the control of the firmware built into its ROM, which analyzes the defect list and controls the formatting. It cannot be interrupted by external commands. Upon completion of formatting, the firmware automatically recalculates the translator (or creates it anew), and the screw becomes ready for use. After that, he, without a single bad block, comes from the factory to the buyer.

3. New technologies

Now it is clear why proprietary utilities do not perform any operations related to direct access to the service area. After all, hiding defects by formatting is almost a complete repair cycle based on external parameters and associated with a clear understanding of each step. And it's enough to do something wrong to ruin the drive. Here's a simple example: a user decided to do "real" low-level formatting by running a ROM routine in technological mode. The process usually lasts 10-60 minutes, but then there is a power failure or a banal freeze - and the propeller is left without a translator, tk. simply does not have time to re-create it. This means that such a device will not be suitable for further work - neither OS nor BIOS will see it. It's scary to even imagine how many drives can be killed in this way, out of simple curiosity or by mistake. Especially if these utilities fall into the hands of dummies who run everything on their computers and press RESET instead. Of course, the disk does not deteriorate irrevocably, and by restarting the formatting, you can bring it back to life. But the thinking of the majority of users is arranged in such a way that when faced with problems (a corpse not defined in the BIOS instead of a screw), many panic, blaming the manufacturers for everything. And they naturally do not need an extra hemorrhoid - it is much more important to make the screw work out the warranty period. Therefore, several years ago, the ability to independently "repair" bad sections - to make a remap - began to be included in the drives. As mentioned earlier, the remap was not used in the factory preparation of drives, but it turned out to be a very successful solution for hiding defects in domestic conditions. The advantages of remap over internal formatting are the absence of transferring the screw to the technological mode, the speed of carrying out and safety for the drive. In addition, in many cases, a remap can be done without demolishing the file system, and without the associated destruction of data. This technology is called automatic defect reassignment, and the process itself is called reassign. Thus, remap and reassign are largely the same, although the term reassign is usually applied to a single sector, and remap to the entire disk.

The remap works as follows: if an error occurs when trying to access a sector, the “smart” controller understands that this sector is faulty, and “on the fly” marks it as BAD. Its address is immediately entered into the defects table (G-list). For many screws, this happens so quickly that the user does not even notice the defect is detected and hidden. During operation, the screw constantly compares the current addresses of the sectors with the addresses from the table and does not refer to the defective sectors. Instead, it moves the heads to the spare area and reads the sector from there. Unfortunately, due to the time taken for long-range positioning, such sectors will appear as small dips in the reading graph. The same will happen when recording. Therefore, the engineers of Quantum went even further and almost eliminated the main drawback of remap, having embodied their ideas in many models of the Fireball series: these drives have one spare sector on each track, remap occurs in this sector, and there are practically no delays.

If an error occurs during normal operation of the OS, automatic remap is extremely rare. This is due to the fact that, on most hard drives, reassign is triggered only when writing. And many operating systems, before writing, checks the sector for integrity, and detecting an error, refuses to write to it. Therefore, in most cases, for the production of remap, the screw must be "asked" about it - to make a forced low-level rewriting of the sector bypassing the standard functions of the OS and BIOS. This is done by a program that can access the screw directly through the ports of the IDE controller. If an error occurs during such recording, the controller will automatically replace this sector from the reserve, and the BAD will disappear.

Most of the so-called "low-level formatting" utilities from manufacturers are based on this principle. All of them, if desired, can be used for screws from other companies (if such programs refuse to work with other people's hard drives, this is done for marketing reasons. For example, Fujitsu suffers from such greed). And of course, the remap functions are present in many universal and free programs, the features of the use of which we will consider a little later. In the meantime, a little more theory :)

The most common myth among users is the assertion that each screw needs its own, "special" program for hiding defects, as well as the fact that remap is a low-level formatting. In fact, this is not the case. Remap is just a kind of recording information by standard means, and in most cases any remap utilities can be applied to any screws. Remap is done not by external programs, but by the screw controller. Only he makes the decision to reassign defective sectors. "Foreign" programs cannot spoil the drive either, since they do not use technological commands, and in normal mode the screw will never allow you to do anything with itself except for standard read-write operations. The only difference between proprietary utilities is the number of write / read / verify attempts for different screws. In order for the controller to "believe" that there is a BAD to be hidden in the sector, one cycle is enough for some hards, and several for others.

4. Again about S.M.A.R.T.

Almost all hard drives released after 1995 have a system of operational monitoring of their condition - S.M.A.R.T. (Self Monitoring And Reporting Technology). This technology allows you to evaluate such important parameters of the drive at any time as the number of hours worked, the number of errors that occurred during the read / write process, and much more. The first hard drives equipped with this system (for example, WD AC21200) had a very imperfect SMART of four to six attributes. But soon the SMART-II standard was developed, and since its appearance, most drives have such a feature as internal diagnostics and self-monitoring. This feature is based on a series of self-contained internal tests that can be run with standard ATA commands, and is designed to provide in-depth monitoring of drive mechanics, disk surfaces, and many other parameters. After running the tests, the drive is obligatory to update the readings in all SMART attributes in accordance with its current state. Testing times can vary from a few seconds (Quantum) to 54 minutes (Fujitsu MPG). SMART tests can be activated, for example, using the MHDD program (console command "smart test"). After running the tests, "strange" phenomena are possible, very similar to those that occur when the defragmenter is running: continuous burning of the HDD indicator and the sound of intensive movement of the heads. This is normal: the screw scans the surface to look for defects. You just need to wait a while until the self-test is over and the screw will calm down.

More recently, the SMART-III specification has appeared, in which there is not only the function of detecting surface defects, but also the ability to repair them "on the fly" and many other innovations. One of its varieties is the Data Lifeguard system used in new Western Digital drives. Its essence is as follows: if there is no access to the screw, it begins to scan the surface on its own, identifying unstable sectors, and when they are detected, it transfers the data to the backup area. Then he reassigns him. Thus, the data is saved even before the real BAD arises in this place. Unlike SMART monitoring, Data Lifeguard cannot be disabled by external commands and works constantly. Therefore, "visible" BAD-blocks on modern Western Digital hard drives almost never appear.

To view the smart status of a hard drive, programs called smart monitors are used. One of them is part of the HddUtil complex for DOS and is called smartudm. You can download it here: www.sysinfolab.com/files/smartudm.zip. This program works with any hard drives and controllers. In addition, this program comes with detailed documentation with a description of all the attributes. There are SMART monitors for Windows 9x, for example, SiGuardian (http://www.siguardian.ru/) and SmartVision (www.acelab.ru/products/pc/utility.smart203.zip) are very popular, but they may not work on some systems. This is explained by the fact that the programs work with the screw directly, through the ports, and the bus mastering drivers of some chipsets interfere with this. Windows XP owners should pay attention to the SmartWiew monitor www.upsystems.com.ua/ - the program works correctly in this system even on VIA chipsets.

There is some relationship between SMART attributes and surface condition. Let's consider those that are directly related to bad blocks:

Reallocated sector count and Reallocated event count: number of reassigned sectors. These attributes show the number of sectors reassigned by the remap in the Grown defect list. They must be zero for new screws! If their value differs from zero, then this means that the screw was already in use, badges appeared on it, and a remap was made to it. And for Fujitsu screws, these attributes can spontaneously increase due to poor-quality power supply. Be careful when buying a used one!

Raw read error rate: number of read errors. For many hard drives (for example, Seagate and Fujitsu) they are always above zero, but if the Value value is within the normal range (green zone), there is nothing to fear. These are "soft" errors that have been successfully corrected by the drive electronics and do not lead to data corruption. It is dangerous when this parameter drops sharply in a short time, passing into the yellow zone. This indicates serious problems in the drive, about the possible appearance of bad data in the near future, and that it is time to back up important data.

Current Pending Secto r: this attribute reflects the contents of the "temporary" defect list, which is present on all modern drives, i.e. the current number of unstable sectors. The screw could not read these sectors the first time. The raw value field of this attribute shows the total number of sectors that the drive currently considers to be remap contenders. If in the future any of these sectors is read (or rewritten) successfully, then it is excluded from the list of applicants. A constant value of this attribute above zero indicates a problem with the drive.

Uncorrectable Sector: shows the number of sectors for which errors could not be corrected with ECC code. If its value is higher than zero, it means that it is time for the screw to do a remap: it is possible that while writing data, the OS will run into this sector and as a result, some important information or system file will be damaged. However, for some screws, for example, for Fujitsu MPG, this attribute for some reason is not reset even after remap, so it is not necessary to trust its readings.

5. Types of defects and reasons for their appearance

It's time to figure it out, and why, in fact, there is such a nuisance as bedy? In UPGRADE # 49, we considered only external causes that contribute to their occurrence. And now it's time to look at the problem from a different point of view - from the side of the hard drive itself. To do this, consider the structure of the sector, as seen by the electronics of the propeller "from the inside":

Rice. 1. Simplified structure of the hard disk sector.

As you can see from Figure 1, everything is much more complicated than it might seem at first glance, even with a disk editor. The sector consists of an identifier header and a data area. The beginning of the sector is marked with a special byte - the address marker (1). It serves to inform the controller that the sector is under the head. Then the cells follow, which contain the unique address of the sector in the CHS format (2) and its checksum - to check the integrity of the recorded address (3). 512 bytes of user data are placed in a separate field (4), to which, during writing, several tens of bytes of redundant information are added, designed to correct reading errors using an ECC code (5). Next to the data, 4 bytes of the cyclic checksum (CRC) of the data are placed, which serves to check the integrity of user data, and to notify the error correction system if it is violated (6). For more reliable operation of the sector with fluctuations in rotation speed, there are bytes-spaces (7). Some hard drives have an additional byte after AM - in it the sector is marked as BAD.

As long as the structure of the format is not broken, the hard drive is working properly, clearly fulfilling its duties - storing information. But if evil forces intervene, and depending on the type of destruction, they manifest themselves as BADs of varying severity.

Defects can be divided into two large groups: physical and logical. Let's consider each of their types in detail.

Physical defects

Surface defects. They arise when the magnetic coating is mechanically damaged inside the sector space, for example, due to scratches caused by dust, aging pancakes or careless handling of the screw. Such a sector should be marked as unusable and removed from circulation.

Servo errors... All modern drives use a system called (voice coil) to move the heads, which, unlike the stepper motor of old screws, does not have any discontinuity of movement. To accurately hit the heads on the tracks in the screws, a feedback system is used, which is guided by special magnetic servo marks applied to the disk. Servo labels are located on each side of each disc. They are evenly spaced along all tracks, and strictly radially, like the spokes in a wheel, forming a servo format. It does not belong to the lower-level format and is not shown in the figure, but it is available in absolutely all modern hard drives, and plays an important role. According to the servo marks, the engine rotation speed is stabilized and the head is held on a given track, regardless of external influences and thermal deformation of the elements.

However, during the use of the propeller, some servo tags may be destroyed. If there are too many dead servo labels, failures will occur in this place when accessing the information track: the head, instead of taking the position it needs and reading the data, will start to jump from side to side. It will look like a bold and particularly arrogant BAD, or even like a group of BAD "s. Their presence is often accompanied by head banging, drive freezing and the inability to fix it with regular utilities. Elimination of such defects is possible only with special programs, by disabling defective tracks, and sometimes For these purposes, some drives have a servo-defect-list that stores information about bad servo tags. Unlike P- and G-lists, the servo-defect-list is used not by the translator, but by the entire screw firmware. access is blocked even by physical parameters, which avoids knocks and disruptions when accessing them.The screw cannot restore the servo format on its own, this is done only at the factory.

Hardware BADs... They arise due to a malfunction of the mechanics or electronics of the drive. Such malfunctions include: head breakage, displacement of disks or a bent shaft as a result of an impact, dusting of the containment area, as well as various glitches in the operation of electronics. Errors of this type are usually catastrophic and cannot be corrected by software.

Logical defects

These errors do not occur due to surface damage, but due to violations of the logic of the sector. They can be divided into correctable and incorrigible. Logical defects have the same external manifestations as physical ones, and they can only be distinguished indirectly, according to the results of various tests.

Correctablelogical defects (soft-bads): appear if the checksum of the sector does not match the checksum of the data written to it. For example, due to interference or power outage during recording, when the screw has already written data to the sector, but did not have time to write the checksum (Fig. 1). At the next reading of such an "unfinished" sector, a failure will occur: the screw first reads the data field, then calculates their checksum and compares what was received with the written one. If they do not match, the drive controller will decide that an error has occurred and will make several attempts to re-read the sector. If this does not help (and it does not help, since the checksum is obviously incorrect), then using the redundancy of the code, he will try to correct the error, and if this does not work, the screw will give an error to the external device. From the operating system side, it will look like BAD. Some screws had an increased tendency to form soft-bads due to errors in the firmware - under certain conditions, checksums were calculated incorrectly; in others it was due to mechanical defects. For example, for IBM DTLA the contact between the board and the HDA was intermittently broken, which led to the loss of power to the HDA at the most inopportune time, including during recording.

The operating system or BIOS cannot fix a logical defect on its own, because before writing to a sector, they check it for integrity, run into an error and refuse to write. At the same time, the screw controller cannot correct this error either: it tries in vain to read this sector from the second, from the third attempt, and when this does not work, it tries to help itself with all its might, adjusting the reading channel and the servo system on the fly. At the same time, the same heartbreaking rattle is heard, so familiar to the owners of badass "woodpeckers". This squeak is not produced by "heads on the surface", as many are accustomed to think, but only by the positioner coil, due to the specific form of the current flowing through it, and it is absolutely safe. The address of the unread sector is added to the temporary defect list by changing the value of the Current Pending Sector attribute in SMART, and is saved there. No remap occurs when reading.

And only forced low-level rewriting of this sector with a special program bypassing BIOS leads to automatic recalculation and rewriting of the checksum, i.e. bad disappears without a trace. You can rewrite it with a disk editor capable of working with the screw directly through the ports, but usually they "overwrite" the entire disk, filling its sectors with zeros. Utilities that do this are freely available from hardware vendors, and are often incorrectly referred to as "low-level formatting software". In fact, these are simple "zeroers", which in no way prevents them from ridding the screw of the bads: if the recording is successful, the soft-bads disappear, and if the recording is unsuccessful, the bad is considered physical, and an auto-remap occurs.

Fatal logic errors... These are errors of the internal format of the hard drive, leading to the same effect as surface defects. They occur when the sector headers are destroyed, for example, due to the action of a strong magnetic field on the screw. But unlike physical defects, they can be corrected by software. And they are named incorrigible only because to fix them it is necessary to do the "correct" low-level formatting, which is difficult for ordinary users due to the lack of specialized utilities. Therefore, in everyday life, such a sector is turned off in the same way as the physical one - with the help of remap. Currently, more and more screws are produced using the ID-less technology (sectors without headers), so soon this type of error will become irrelevant.

"Adaptive" badges... Despite the fact that the screws are very accurate devices, during their mass production, a scatter of parameters of mechanics, radio components, magnetic coatings and heads inevitably arises. This did not interfere with old drives, but in modern screws with their huge recording density, the slightest deviations in the dimensions of parts or in signal amplitudes can lead to a deterioration in the properties of the product, the appearance of errors, up to a complete loss of its performance. Therefore, all modern screws are individually tuned during manufacturing, during which such parameters of electrical signals are selected, at which the device works better. This setting is carried out by the ROM program during technological surface scanning. In this case, so-called adaptives are generated - variables that contain information about the features of a particular HDA. Adaptives are saved on pancakes in the service area, and sometimes in Flash memory on the controller board.

If, during the operation of the screw, the adapters are destroyed (this can happen as a result of errors in the screw itself, static electricity or due to poor-quality power supply), then the consequences can be unpredictable: from a banal heap of bads to the complete inoperability of the device, with a refusal to go to readiness for interface. "Adaptive" badges differ from the usual ones in that they are "floating": today they exist, and tomorrow they can disappear and appear in a completely different place. It is useless to remap such a screw - ghost defects will appear again and again. And the disc surface can be in perfect condition! Adaptive badges are treated by running selfscan - an internal testing program similar to the one used at the factory in the manufacture of screws. At the same time, new adaptives are created, and the screw returns to its normal state. This is done under the conditions of branded service centers.

Impending defects

These are areas of the surface on which a pronounced defect has not yet formed, but problems with the reading speed are already noticeable. This is due to the fact that the sector is not read by the controller the first time, and the screw is forced to rotate the disk several times, trying to read it without errors. If you still manage to read the data, the screw will not tell the operating system anything, and the error will remain unnoticed until a real BAD block appears in this place. As a rule, it immediately turns out that it was in this place that a very important file was stored, in a single copy, and it is no longer possible to save it. Therefore, the disks need to be tested periodically. This can be done with Scandisk or Norton Disk Doctor in surface testing mode, but better - with a special utility that works independently of the file system and is able to identify emerging BADs, measuring the time to read each sector.

The practice of working with sectors is described.

For those who are poorly familiar with a computer and do not know what DOS is, it is better not to repeat everything that will be described in this article, since here we will talk about how to restore damaged HDD sectors.

And so you found out that you constantly have a disk check at boot, or the hard drive began to slow down a lot. You are talking about scanning with some utility in read mode (read) or any program from this article. Thus, you made sure that you have slow sectors that respond longer than 500 ms, or BAD sectors, then this article is for you.

How to fix broken sectors

If your disk periodically disappears or does not see each other at all, then this is already a problem, most likely with the controller, cable (loop) or power supply, but we will talk about BED sectors and very slowly read cells, in general about hard disk software errors ...

So you found (HDD checker program) that you have slow sectors on your hard disk (usually red or brown). The decision to apply low-level formatting (Erase), we do it with the program MHDD and just, forget the programs running from under windows, they won't help you like HDDscan and Victoria.

Attention!!! All the operations described below can lead to partial or complete deletion of information on your hard disk drive (HDD).

So we boot from the boot disk where there is this MHDD program, these are the collections of STEA Live, Hiren boot cd, or make your own boot disk or USB flash drive.

Stage 1. Getting rid of slow (red) sectors

Launch MHDD, type the command Erase, the list of all commands can be viewed by the F1 command, the program will ask you to specify the scan range, do not change anything, press Enter by default, wait. If the red sectors remain, then you will have to run the command Erase waits

Stage 2. Getting rid of bad sectors

We launch MHDD, type the Remap command, and the program will automatically scan the hard disk and replace bad sectors with spare ones, I do not recommend running this program with a large number of red and bad sectors in the hard disk partitions.

You can also clean the HDD from bad sectors manually, while not the entire hard drive, but partly along the range of addresses.

We execute the command SCAN, as soon as the BAD sector appears, we remember its number, stop the ESC process, run the command Erase and we indicate the range in this case, if there is one bad sector, then its number and the next, that is, we add one, then we run the command again Scan and we look at the appearance of new broken sectors, we repeat the procedure.

The video shows the whole process well:

If scanning takes a very long time for you, then no program will help you. And you will have to buy a new hard drive already.

P.S .: I am attaching a link to a video showing the operation of the MHDD program for general information

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18 comments to write How to recover damaged bad (BAD) sectors of HDD

Well, you give a hint. booted from MHDD wrote how you have it in the first paragraph of Erase and erased all Windows did not help even restore through the archive right now I put on a new Windows.

Dear yura200, if you would carefully read the article, it says that Erase- this is low-level formatting, well, I hope the word formatting, do you understand what it does?)

So what for to write the first point, write erase well that after installing Windows it was able to roll back right now all the way. The most interesting thing is that I wanted to start this business from the D disk and there are family vidyashki pictures that would have grabbed grief, but it's good that MHDD did not see the D disk and only the C disk was formatted. I push here so that others do not rub the whole screw. And where in what place in the text do you say that Erase is formatting? When I used Mhdd, I used erase when grouting block ills. Correct the text.

yura200, I am very sorry that you have experienced such difficulties, but all that you do is your personal desire. In the text, the third paragraph:

So you found (HDD checker program) that you have slow sectors on your hard disk (usually red or brown). Decision to apply low-level formatting (Erase)

P.S.: And for interest you can look at the translation, it also says a lot erase- erase, delete (from memory).

Good afternoon.

Can you tell me how to make the program work on a laptop? Neither MHDD nor Victoria can see my hard drive.

Danila Are you sure you have an HDD in your laptop? and not SSD, because with the second disks, the MHDD and Victoria programs do not work.

Dear! If you see orange or red on your disk during the test, or even an X in a square, then do not torment him, he is finished. These people are just trying to somehow support them with a stroke, and then you see what they then become, and the glands, after you have thrown off the pictures, are one way to a well-deserved rest. And don't listen to or read the recovery bullshit.

Indeed, on the ASUS X552EA laptop, the MHDD program does not see a 500 GB HDD WD (not SSD, and not hybrid, normal).

I played with the BIOS - this way and that ... alas, the MHDD program opens from the bootable USB flash drive, but does not see the disk, no matter how hard I tried.

It is necessary to set the HDD operation mode SATA Standart IDE INSTEAD OF SATA AHCI

I want to check and fix the bad sectors in dos (I checked it in winows before with Victoria) But I can't switch from AHCI to IDE in BIOS, there is nothing similar. Hp laptop (they wrote that they removed this function) How can you help?

Put this hard drive in the system unit and run it there and, if necessary, configure the BIOS.

Respect and respect to the author! The user does not have funds for a new hard, and a system engineer is vital ..., so I found along the above trajectory that in addition to the first 42 gigs of crosses, there are two more thirds of the working space .., and the person is grateful!

Thanks a lot for the article!

It was necessary to restore the functionality of the old disk. I scanned its state with the MHDD program (I found it on an old CD-reanimator), found several dozen "red" sectors, but did not know that the ERASE command was exactly what I needed. I thought it was a simple erasure of information.

Now, after processing the disk with ERASE, I scanned it again. Result - not a single BED!

The question is if there are bads in the first 4 gigs and the last 4 gigs, and there are 2047 of them, is there any reason to strain to recover?

Andrey unless you need to pop the leftover data from the hard drive, but I wouldn't use such a drive in the future.

Is 653 bads really bad? Erase won't help?

Max yes this is really bad

Hello bortvlad. Is it worth bothering with the treatment of bad? Windows so monitors and corrects cells as much as it can. And he will not write down the info in the bed. The loss of speed is negligible. And replacing cells from the spare area changes the desired table, which, in my opinion, will only speed up the death of the HDD. If it's really a very tight low-level formatting and use the disk for archiving movies, games .... What can you say about this software: Low Lewel Format Tool?

In this article, we will talk about bad sectors on the hard disk what they are and how to treat them. But first, let's find out where they come from?

Everyone knows that the hard drive consists of clusters are miniature cells. Each of the clusters is a logical storage of information, where files are constantly written. The combination of all clusters ensures the correct operation of the entire computer.

Bad block or bad sector is an unreadable disk sector that contains bad memory cells.

Such a hard disk is no longer suitable for working with the operating system, but you can try to use it as an external storage device, like a "large flash drive". If you use such a hard disk for storing data, it is advisable to cut off the place where the bad blocks are located using a program for working with hard drives. For example, Acronis DiskDirector.

Bad sector on the hard disk

Most frequent the reason for the appearance of bad sectors- this is the natural wear and tear of the drive, i.e. if the hard disk has been working for many years, then simply due to the large number of write and read cycles to one sector or another, the hard disk begins to slowly but surely fail. As a rule, this is more than 10,000 hours of work. This increase in the access time to the sector is manifested, that is, for a new serviceable cell it is on the order of 10-15 ms, then indicators of more than 150 ms indicate a strong wear of the drive. If one sector fails, then others will soon begin to fail, which means that you should think about replacing the hard drive, or at least copy the information you need.

Why bad sectors appear - we figured it out, now we will discuss how to identify them.

Victoria

Maybe you already know about the program Victoria is a program specially created for deep diagnostics of the hard drive. Victoria is available in 2 versions: with a graphical shell and without it (DOS version).

Received Smart in Victoria program

This is already a proven hard drive, and its main parameters are shown here, i.e. data SMART... During the surface test, the response time to the request for each sector can be obtained. The time is indicated from 5 milliseconds to 1.5 seconds and higher, the less - the better, the faster our hard drive reacts.

As for Smart, here you can be guided by the number of "", the more, the better. Judging by the quantity " Hardware ECC recovered"- it's time to change the hard drive.

1 Raw read error rate 100 253 6 0
3 Spin-up time 97 97 0 0
4 Number of spin-up times 94 94 20 6522
5 Reallocated sector count 100 100 36 0
7 Seek error rate 87 60 30 564751929
9 Power-on time 83 83 0 14937
10 Spin-up retries 100 100 97 0
12 Start / stop count 94 94 20 6273
187 Reported UNC error 1 1 0 103
189 High Fly writes 100 100 0 0
190 Airflow temperature 55 48 45 45 ° C / 113 ° F
194 HDA Temperature 45 52 0 45 ° C / 113 ° F
195 Hardware ECC recovered 80 64 0 100816244
197 Current pending sectors 100 100 0 0
198 Offline scan UNC sectors 100 100 0 0
199 Ultra DMA CRC errors 200 200 0 1
200 Write error rate 100 253 0 0
202 DAM errors count 100 253 0 0

Victoria also knows how to do many other operations with HDD, up to sector closings.

With this function, bad sectors can be closed however, this will only slightly delay the failure.

You can download the Victoria program on the website, it is free and does not require installation on a computer.

If, for some reason, you did not like Victoria, then there is always an alternative, and many others, such as: Active boot disk, HDD Regenerator, R-Studio etc.

Broken sectors are not treated, but closed, and their disk space will be assigned to workers.