Surely many users of PCs and laptops had to deal with all sorts of problems that arose with the hard drive. In this article, we will try to answer the basic questions regarding the operation of the hard drive and analyze it with a specific example? what to do when the hard drive slows down, how to check the serviceability of the media and whether it is worth spending your nerves and time on it.
As an example, take one of the most popular hard drives that thousands of computers and laptops are equipped with - a Seagate hard drive. The main problems of the “experimental” are the freezing of the operating system or even refusal to load, various errors, creaking and clicking. So, how to check the health of the hard drive on the computer?
Software
One of the most interesting (and free) from a technical point of view programs for checking the hard drive is HDDScan, which can be downloaded from the official website on request in any search engine.
First of all, it is necessary to check the performance of the SMART hard drive (built-in technology that evaluates the hard drive with self-diagnosis equipment with the prediction of the remaining “life” time), and then a qualitative test of the media surface will be passed with the identification of bad sectors (bad blocks).
But before checking the status of the hard disk for any problems, we will make a small digression to understand the principle of the HDDScan utility, explaining in more detail what SMART, bad blocks are and why some of them cannot be "cured", especially since Feedback on this program is left by users, who have not fully understood what blocks, tracks and sectors are.
Principle of operation
Winchester consists of glass and aluminum plates, which are coated with a layer of technical ferromagnetic material. That is, simply put, a hard disk is a magnetic recording device. The heads, which are located on the surface of the carrier, hover at a height of 10-13 nm and never touch the surface itself, which, incidentally, is very easy to damage.
The conveyor at the last stages of production of the hard disk carries out low-level formatting, which forms the “map” of the hard drive, dividing it into tracks and sectors. Special servo tags are also applied, which are responsible for the exact hit of the head on the desired track of the hard drive.
Sectors
The unit of measure for a hard drive is a sector that consists of 512 bytes of data, and to format the media at a low level, special and very expensive equipment is required - “Servoraiter”, therefore it is performed only in the factory, and all the information recorded using this equipment will never be overwritten in any service. If someone promises you to check the status of the hard drive and perform low-level formatting, be aware that this cannot be done at home.
The manufacturer writes only official information to the sectors: the physical address of the sector itself and the address marking indicating the beginning of the track. This information is often called hard disk markup, and it is needed for the media to work correctly so that the hard drive heads fall accurately onto the desired sector and track for reading and writing data.
After acquiring a hard drive, the user can access almost all of its volume, with the exception of service information, which contains MBR (master boot record) and built-in utility utilities. The area of the disk where this data is located has a greater magnetization, preventing the user from accidentally or intentionally deleting service information.
Firmware
Data on sectors, tracks and their numbers are presented in a special table that is not available for BIOS and any OS. This table is located in the service area, which is a kind of mini-operating system and, together with Firmware firmware, controls all the actions of the hard drive. Some users ask themselves: is it necessary to update or completely change the firmware before checking the hard drive on a laptop or on a normal PC? The answer is unequivocal: no. All modern media do not need any firmware update.
All the information that is recorded in the service area, together with the firmware, is a disk passport: SMART attributes, a table with identified defects, bad blocks that cannot be fixed, and reassigned sectors.
Sector Types
Before checking the external hard drive for proper operation, it is important to know that there are three types of bad sectors: physical, logical, and software. When trying to read a bad sector, the operating system repeatedly tries to load the data several times, and if this fails, the OS recognizes the sector as bad and writes all the necessary information to the normal sector, which is located on the backup track. Such a process is called Remapping, or in common people remap.
And to carry out or postpone a remap, only the hard drive controller decides, and not the user or third-party software, which can only “hint” to the hard drive about the need for a remap. Before checking the hard drive for serviceability, the built-in utilities always check the defect table, where all bad sectors fall, which were either reassigned by the system or marked as unsuitable for recovery.
In total, two tables with defects are provided: the factory one (Primary List), which reflects the results of initial tests on the conveyor with bad blocks already marked, and the current one (Grown List), which is filled up as current problems accumulate.
Bad sectors. How to fix them?
Before checking the hard drive for serviceability, you need to know about the types of bad sectors and the possibility of their further rehabilitation in case of damage.
According to reviews, physically faulty bad blocks cannot be restored by any formatting. The only thing that can be done is to reassign bad sectors to spare from backup tracks. A significant disadvantage of this method will be a decrease in the performance of the hard drive, since the heads will have to travel a greater distance and make additional movements to find information on the backup tracks.
Physical bad sectors are mechanical defects of the hard disk: a damaged magnetic layer of the media surface, chips, scratches, etc. Very often, such problems occur after a hard drive hurt, when one or more heads were damaged and, attached to the magnetic drive scratched its surface. Overheating or vibration, as evidenced by the reviews, can also serve as the causes of bad sectors. In this case, the bad block must always be replaced and reassigned by the normal sector from the backup track.
Squeaking and clicking
If before you check the hard drive for performance, you often heard a creak or click inside the system unit, then the reason in most cases lies in the positioner of the head of the hard drive. The carrier tries to read the information over and over, wearing out the positioner in a certain position, resulting in a small creak.
The cause of the clicks may be the reassignment of the tracks of bad sectors to backup. They are not always nearby, so the heads often and sharply change their direction from side to side, as a result of which specific clicks are heard.
Another possible cause of clicking and squeaking is a violation of the factory marking as a result of the mechanical stress described in the section above. Servo tags can be destroyed, and the head can no longer accurately get to the sector it needs, therefore, repeated attempts by the carrier to read information and get into its own “track” are heard.
According to reviews, the only panacea for squeaks and clicks that is accessible to a simple user is disk defragmentation with the built-in utilities of the operating system, which if it does not help get rid of the problem, it will at least make the hard drive work for some more time.
How to check the hard drive for good sectors?
Logical bad blocks that arise as a result of errors in the sector logic can be divided into correctable and faulty ones. Consider in which case it is impossible to fix a logical bad block.
As mentioned above, each sector of the hard drive, in addition to user data, carries part of the service information about the markup and physical addresses that determine the beginning of the sector. If this information was damaged for various reasons (mechanical or physical impact), then it can only be restored in the factory, which is very problematic for the average user.
But if before checking the hard drive for serviceability you did not hit and did not overheat it, that is, service information in the sectors is not broken, you can restore data and media performance by the checksum of each sector (ECC - error correction code). This data is contained in each unit of the media, and it is also used by utilities for the rehabilitation of the hard drive.
If you believe the reviews, various kinds of software errors on the hard disk like an incorrectly marked sector or track are “treated” by the usual formatting or software built into the operating system.
Summarizing
After we figured out the principle of the hard drive and identified the points that can be fixed and which cannot, we can safely start testing the disk with the HDDScan utility and watch the results, making appropriate conclusions for ourselves. There are a lot of positive reviews about this software on the Internet, so you can recommend it to both novice users and experienced professionals.
After you know the current status of SMART, you can make a prediction - restore this drive or purchase a new one.