The structure and principle of operation of a hard drive. Hard drive - what is it? Features of hard drives How to read the designation on hard drives

Hard drives, or hard drives as they are also called, are one of the most important components of a computer system. Everyone knows about this. But not every modern user even has a basic understanding of how a hard drive functions. The principle of operation, in general, is quite simple for a basic understanding, but there are some nuances, which will be discussed further.

Questions about the purpose and classification of hard drives?

The question of purpose is, of course, rhetorical. Any user, even the most entry-level one, will immediately answer that a hard drive (aka hard drive, aka Hard Drive or HDD) will immediately answer that it is used to store information.

In general, this is true. Do not forget that on the hard drive, in addition to the operating system and user files, there are boot sectors created by the OS, thanks to which it starts, as well as certain labels by which you can quickly find the necessary information on the disk.

Modern models are quite diverse: regular HDDs, external hard drives, high-speed solid-state drives (SSDs), although they are not generally classified as hard drives. Next, it is proposed to consider the structure and principle of operation of a hard drive, if not in full, then at least in such a way that it is enough to understand the basic terms and processes.

Please note that there is also a special classification of modern HDDs according to some basic criteria, among which are the following:

• method of storing information;
• media type;
• way of organizing access to information.

Why is a hard drive called a hard drive?

Today, many users are wondering why they call hard drives related to small arms. It would seem, what could be common between these two devices?

The term itself appeared back in 1973, when the world's first HDD appeared on the market, the design of which consisted of two separate compartments in one sealed container. The capacity of each compartment was 30 MB, which is why the engineers gave the disk the code name “30-30”, which was fully in tune with the brand of the “30-30 Winchester” gun, popular at that time. True, in the early 90s in America and Europe this name almost fell out of use, but it still remains popular in the post-Soviet space.

The structure and principle of operation of a hard drive

But we digress. The principle of operation of a hard drive can be briefly described as the processes of reading or writing information. But how does this happen? In order to understand the principle of operation of a magnetic hard drive, you first need to study how it works.

The hard drive itself is a set of plates, the number of which can range from four to nine, connected to each other by a shaft (axis) called a spindle. The plates are located one above the other. Most often, the materials for their manufacture are aluminum, brass, ceramics, glass, etc. The plates themselves have a special magnetic coating in the form of a material called platter, based on gamma ferrite oxide, chromium oxide, barium ferrite, etc. Each such plate is about 2 mm thick.

Radial heads (one for each plate) are responsible for writing and reading information, and both surfaces are used in the plates. For which it can range from 3600 to 7200 rpm, and two electric motors are responsible for moving the heads.

In this case, the basic principle of operation of a computer hard drive is that information is not recorded just anywhere, but in strictly defined locations, called sectors, which are located on concentric paths or tracks. To avoid confusion, uniform rules apply. This means that the principles of operation of hard drives, from the point of view of their logical structure, are universal. For example, the size of one sector, adopted as a uniform standard throughout the world, is 512 bytes. In turn, sectors are divided into clusters, which are sequences of adjacent sectors. And the peculiarities of the operating principle of a hard drive in this regard are that the exchange of information is carried out by entire clusters (an entire number of chains of sectors).

But how does information reading happen? The principles of operation of a hard magnetic disk drive are as follows: using a special bracket, the reading head is moved in a radial (spiral) direction to the desired track and, when rotated, is positioned above a given sector, and all heads can move simultaneously, reading the same information not only from different tracks , but also from different disks (plates). All tracks with the same serial numbers are usually called cylinders.

In this case, one more principle of hard drive operation can be identified: the closer the reading head is to the magnetic surface (but does not touch it), the higher the recording density.

How is information written and read?

Hard drives, or hard drives, were called magnetic because they use the laws of the physics of magnetism, formulated by Faraday and Maxwell.

As already mentioned, plates made of non-magnetic sensitive material are coated with a magnetic coating, the thickness of which is only a few micrometers. During operation, a magnetic field appears, which has a so-called domain structure.

A magnetic domain is a magnetized region of a ferroalloy strictly limited by boundaries. Further, the principle of operation of a hard disk can be briefly described as follows: when exposed to an external magnetic field, the disk’s own field begins to be oriented strictly along the magnetic lines, and when the influence stops, zones of residual magnetization appear on the disks, in which the information that was previously contained in the main field is stored .

The reading head is responsible for creating an external field when writing, and when reading, the zone of residual magnetization, located opposite the head, creates an electromotive force or EMF. Further, everything is simple: a change in EMF corresponds to one in binary code, and its absence or termination corresponds to zero. The time of change of the EMF is usually called a bit element.

In addition, the magnetic surface, purely from computer science considerations, can be associated as a certain point sequence of information bits. But, since the location of such points cannot be calculated absolutely accurately, you need to install some pre-designated markers on the disk that help determine the desired location. Creating such marks is called formatting (roughly speaking, dividing the disk into tracks and sectors combined into clusters).

Logical structure and principle of operation of a hard drive in terms of formatting

As for the logical organization of the HDD, formatting comes first here, in which two main types are distinguished: low-level (physical) and high-level (logical). Without these steps, there is no talk of bringing the hard drive into working condition. How to initialize a new hard drive will be discussed separately.

Low-level formatting involves physical impact on the surface of the HDD, which creates sectors located along the tracks. It is curious that the principle of operation of a hard drive is such that each created sector has its own unique address, which includes the number of the sector itself, the number of the track on which it is located, and the number of the side of the platter. Thus, when organizing direct access, the same RAM accesses directly to a given address, rather than searching for the necessary information across the entire surface, due to which performance is achieved (although this is not the most important thing). Please note that when performing low-level formatting, absolutely all information is erased, and in most cases it cannot be restored.

Another thing is logical formatting (in Windows systems this is quick formatting or Quick format). In addition, these processes are also applicable to the creation of logical partitions, which are a certain area of ​​the main hard drive that operate on the same principles.

Logical formatting primarily affects the system area, which consists of the boot sector and partition tables (Boot record), file allocation table (FAT, NTFS, etc.) and the root directory (Root Directory).

Information is written to sectors through the cluster in several parts, and one cluster cannot contain two identical objects (files). Actually, the creation of a logical partition, as it were, separates it from the main system partition, as a result of which the information stored on it is not subject to change or deletion in the event of errors and failures.

Main characteristics of HDD

It seems that in general terms the principle of operation of a hard drive is a little clear. Now let's move on to the main characteristics, which give a complete picture of all the capabilities (or shortcomings) of modern hard drives.

The operating principle of a hard drive and its main characteristics can be completely different. To understand what we are talking about, let’s highlight the most basic parameters that characterize all information storage devices known today:

• capacity (volume);
• performance (data access speed, reading and writing information);
• interface (connection method, controller type).

Capacity represents the total amount of information that can be written and stored on a hard drive. The HDD production industry is developing so quickly that today hard drives with capacities of about 2 TB and higher have come into use. And, as it is believed, this is not the limit.

The interface is the most significant characteristic. It determines exactly how the device is connected to the motherboard, which controller is used, how reading and writing are done, etc. The main and most common interfaces are IDE, SATA and SCSI.

Disks with an IDE interface are inexpensive, but the main disadvantages include a limited number of simultaneously connected devices (maximum four) and low data transfer speeds (even if they support Ultra DMA direct memory access or Ultra ATA protocols (Mode 2 and Mode 4). Although their use is believed to increase the read/write speed to 16 MB/s, in reality the speed is much lower. In addition, to use the UDMA mode, you need to install a special driver, which, in theory, should be supplied. complete with motherboard.

When talking about the principle of operation of a hard drive and its characteristics, we cannot ignore which is the successor to the IDE ATA version. The advantage of this technology is that the read/write speed can be increased to 100 MB/s through the use of the high-speed Fireware IEEE-1394 bus.

Finally, the SCSI interface, compared to the previous two, is the most flexible and fastest (write/read speeds reach 160 MB/s and higher). But such hard drives cost almost twice as much. But the number of simultaneously connected information storage devices ranges from seven to fifteen, the connection can be made without turning off the computer, and the cable length can be about 15-30 meters. Actually, this type of HDD is mostly used not in user PCs, but on servers.

Performance, which characterizes the transfer speed and I/O throughput, is usually expressed in terms of transfer time and the amount of sequential data transferred and expressed in MB/s.

Some additional options

Speaking about what the operating principle of a hard drive is and what parameters affect its functioning, we cannot ignore some additional characteristics that may affect the performance or even the lifespan of the device.

Here, the first place is the rotation speed, which directly affects the time of search and initialization (recognition) of the desired sector. This is the so-called latent search time - the interval during which the required sector rotates towards the read head. Today, several standards have been adopted for spindle speed, expressed in revolutions per minute with a delay time in milliseconds:

• 3600 - 8,33;
• 4500 - 6,67;
• 5400 - 5,56;
• 7200 - 4,17.

It is easy to see that the higher the speed, the less time is spent searching for sectors, and in physical terms, per revolution of the disk before setting the head to the desired platter positioning point.

Another parameter is the internal transmission speed. On external tracks it is minimal, but increases with a gradual transition to internal tracks. Thus, the same defragmentation process, which is moving frequently used data to the fastest areas of the disk, is nothing more than moving it to an internal track with a higher read speed. External speed has fixed values ​​and directly depends on the interface used.

Finally, one of the important points is related to the presence of the hard drive's own cache memory or buffer. In fact, the principle of operation of a hard drive in terms of buffer use is somewhat similar to RAM or virtual memory. The larger the cache memory (128-256 KB), the faster the hard drive will work.

Main requirements for HDD

There are not so many basic requirements that are imposed on hard drives in most cases. The main thing is long service life and reliability.

The main standard for most HDDs is a service life of about 5-7 years with an operating time of at least five hundred thousand hours, but for high-end hard drives this figure is at least a million hours.

As for reliability, the S.M.A.R.T. self-testing function is responsible for this, which monitors the condition of individual elements of the hard drive, carrying out constant monitoring. Based on the collected data, even a certain forecast of the occurrence of possible malfunctions in the future can be formed.

It goes without saying that the user should not remain on the sidelines. So, for example, when working with a HDD, it is extremely important to maintain the optimal temperature regime (0 - 50 ± 10 degrees Celsius), avoid shakes, impacts and falls of the hard drive, dust or other small particles getting into it, etc. By the way, many will It is interesting to know that the same particles of tobacco smoke are approximately twice the distance between the read head and the magnetic surface of the hard drive, and human hair - 5-10 times.

Initialization issues in the system when replacing a hard drive

Now a few words about what actions need to be taken if for some reason the user changed the hard drive or installed an additional one.

We will not fully describe this process, but will focus only on the main stages. First, you need to connect the hard drive and look in the BIOS settings to see if new hardware has been detected, initialize it in the disk administration section and create a boot record, create a simple volume, assign it an identifier (letter) and format it by selecting a file system. Only after this the new “screw” will be completely ready for work.

Conclusion

That, in fact, is all that briefly concerns the basic functioning and characteristics of modern hard drives. The principle of operation of an external hard drive was not fundamentally considered here, since it is practically no different from what is used for stationary HDDs. The only difference is the method of connecting the additional drive to a computer or laptop. The most common connection is via a USB interface, which is directly connected to the motherboard. At the same time, if you want to ensure maximum performance, it is better to use the USB 3.0 standard (the port inside is colored blue), of course, provided that the external HDD itself supports it.

Otherwise, I think that many people have at least a little understood how a hard drive of any type functions. Perhaps too many topics were given above, especially even from a school physics course, however, without this, it will not be possible to fully understand all the basic principles and methods inherent in the technologies for producing and using HDDs.

Greetings to all blog readers. Many people are interested in the question of how a computer hard drive works. Therefore, I decided to devote today’s article to this.

A computer's hard drive (HDD or hard drive) is needed to store information after the computer is turned off, in contrast to RAM () - which stores information until the power supply is cut off (until the computer is turned off).

A hard drive can rightfully be called a real work of art, only an engineering one. Yes Yes exactly. Everything inside is so complicated. At the moment, all over the world, the hard drive is the most popular device for storing information, it is on a par with devices such as flash memory (flash drives), SSD. Many people have heard about the complexity of the hard drive and are perplexed as to how it fits so much information, and therefore would like to know how the computer hard drive is structured or what it consists of. Today there will be such an opportunity).

A hard drive consists of five main parts. And the first of them - integrated circuit, which synchronizes the disk with the computer and manages all processes.

The second part is the electric motor(spindle), causes the disk to rotate at a speed of approximately 7200 rpm, and the integrated circuit maintains the rotation speed constant.

And now the third, probably the most important part is the rocker arm, which can both write and read information. The end of the rocker arm is usually split to allow multiple discs to be operated at once. However, the rocker head never makes contact with the discs. There is a gap between the surface of the disc and the head, the size of this gap is approximately five thousand times smaller than the thickness of a human hair!

But let's still see what happens if the gap disappears and the rocker head comes into contact with the surface of the rotating disk. We still remember from school that F=m*a (Newton’s second law, in my opinion), from which it follows that an object with a small mass and a huge acceleration becomes incredibly heavy. Considering the enormous rotation speed of the disk itself, the weight of the rocker head becomes very, very noticeable. Naturally, disk damage is inevitable in this case. By the way, this is what happened to the disk in which this gap disappeared for some reason:

The role of friction force is also important, i.e. its almost complete absence, when the rocker begins to read information, while moving up to 60 times per second. But wait, where is the engine that drives the rocker arm, and at such a speed? In fact, it is not visible, because it is an electromagnetic system that works on the interaction of 2 forces of nature: electricity and magnetism. This interaction allows you to accelerate the rocker to the speed of light, in the literal sense.

Fourth part- the hard drive itself is where information is written and read from; by the way, there can be several of them.

Well, the fifth and final part of the hard drive design is, of course, the case into which all other components are installed. The materials used are as follows: almost the entire body is made of plastic, but the top cover is always metal. The assembled housing is often called a “hermetic zone”. There is an opinion that there is no air inside the containment zone, or rather, that there is a vacuum there. This opinion is based on the fact that at such high speeds of rotation of the disk, even a speck of dust that gets inside can do a lot of bad things. And this is almost true, except that there is no vacuum there - but there is purified, dried air or neutral gas - nitrogen, for example. Although, perhaps in earlier versions of hard drives, instead of purifying the air, it was simply pumped out.

We were talking about components, i.e. what does a hard drive consist of?. Now let's talk about data storage.

How and in what form is data stored on a computer’s hard drive?

Data is stored in narrow tracks on the surface of the disk. During production, more than 200 thousand of these tracks are applied to the disc. Each of the tracks is divided into sectors.

Maps of tracks and sectors allow you to determine where to write or read information. Again, all information about sectors and tracks is located in the memory of the integrated circuit, which, unlike other components of the hard drive, is located not inside the case, but outside and usually at the bottom.

The surface of the disk itself is smooth and shiny, but this is only at first glance. Upon closer inspection, the surface structure turns out to be more complex. The fact is that the disk is made of a metal alloy coated with a ferromagnetic layer. This layer does all the work. The ferromagnetic layer remembers all the information, how? Very simple. The rocker head magnetizes a microscopic area on the film (ferromagnetic layer), setting the magnetic moment of such a cell to one of the states: o or 1. Each such zero and one are called bits. Thus, any information recorded on a hard drive, in fact, represents a certain sequence and a certain number of zeros and ones. For example, a good quality photograph occupies about 29 million of these cells, and is scattered across 12 different sectors. Yes, it sounds impressive, but in reality, such a huge number of bits takes up a very small area on the surface of the disk. Each square centimeter of a hard drive's surface contains several tens of billions of bits.

How a hard drive works

We have just looked at the hard drive device, each of its components separately. Now I propose to connect everything into a certain system, thanks to which the very principle of operation of the hard drive will be clear.

So, the principle on which a hard drive works next: when the hard drive is put into operation, this means that either writing is being done to it, or information is being read from it, or from it, the electric motor (spindle) begins to gain momentum, and since the hard drives are attached to the spindle itself, accordingly they go with it also begin to rotate. And until the revolutions of the disk(s) have reached such a level that an air cushion is formed between the rocker head and the disk, the rocker is located in a special “parking zone” to avoid damage. This is what it looks like.

As soon as the speed reaches the desired level, the servo drive (electromagnetic motor) moves the rocker arm, which is already positioned in the place where information needs to be written or read from. This is precisely facilitated by an integrated circuit that controls all movements of the rocker.

There is a widespread opinion, a kind of myth, that at times when the disk is “idle”, i.e. No read/write operations are temporarily performed with it, and the hard drives inside stop rotating. This is truly a myth, because in fact, the hard drives inside the case rotate constantly, even when the hard drive is in power-saving mode and nothing is written to it.

Well, we have looked at the device of a computer hard drive in detail. Of course, within the framework of one article, it is impossible to talk about everything related to hard drives. For example, this article did not talk about - this is a big topic, I decided to write a separate article about it.

I found an interesting video about how a hard drive works in different modes

Thank you all for your attention, if you have not yet subscribed to updates on this site, I highly recommend doing so so as not to miss interesting and useful materials. See you on the blog pages!

A hard drive is needed to install the operating system, programs and store various user files (documents, photos, music, movies, etc.).

Hard drives differ in capacity, which determines the amount of data it can store, speed, which determines the performance of the entire computer, and reliability, which depends on its manufacturer.

Conventional hard drives (HDD) have a large capacity, low speed and low cost. The fastest are solid-state drives (SSD), but they have a small capacity and are much more expensive. An intermediate option between them are hybrid disks (SSHD), which have sufficient capacity, are faster than conventional HDDs and are slightly more expensive.

Western Digital (WD) hard drives are considered the most reliable. The best SSD drives are produced by: Samsung, Intel, Crucial, SanDisk, Plextor. More budget options can be considered: A-DATA, Corsair, GoodRAM, WD, HyperX, since they have the least problems. And hybrid drives (SSHD) are mainly produced by Seagate.

For an office computer that is used primarily for working with documents and the Internet, a regular hard drive from the inexpensive WD Blue series with a capacity of up to 500 GB is sufficient. But 1 TB disks are optimal today, since they are not much more expensive.

For a multimedia computer (video, simple games), it is better to use a 1 TB WD Blue drive as an additional one for storing files, and install a 120-128 GB SSD as the main one, which will significantly speed up the operation of the system and programs.

For a gaming computer, it is advisable to take an SSD with a capacity of 240-256 GB; you can install several games on it.
Hard drive A-Data Ultimate SU650 240GB

As a more economical option for a multimedia or gaming PC, you can purchase one Seagate hybrid drive (SSHD) with a capacity of 1 TB; it is not as fast as an SSD, but still slightly faster than a regular HDD drive.
Hard drive Seagate FireCuda ST1000DX002 1TB

Well, for a powerful professional PC, in addition to the SSD (120-512 GB), you can take a fast and reliable WD Black hard drive of the required volume (1-4 GB).

I also recommend purchasing a high-quality Transcend external drive with a USB 3.0 interface for 1-2 TB for the system and files that are important to you (documents, photos, videos, projects).
Hard drive Transcend StoreJet 25M3 1 TB

2. Disk types

Modern computers use both classic hard drives on magnetic platters (HDD) and faster solid-state drives based on memory chips (SSD). There are also hybrid disks (SSHD), which are a symbiosis of HDD and SSD.

The hard disk (HDD) has a large capacity (1000-8000 GB), but low speed (120-140 MB/s). It can be used both to install the system and store user files, which is the most economical option.

Solid state drives (SSD) have a relatively small volume (120-960 GB), but very high speed (450-550 MB/s). They cost significantly more and are used to install the operating system and some programs to increase the speed of the computer.

A hybrid drive (SSHD) is simply a hard drive with a small amount of faster memory added to it. For example, this might look like 1TB HDD + 8GB SSD.

3. Application of HDD, SSD and SSHD drives

For an office computer (documents, Internet), it is enough to install one regular hard drive (HDD).

For a multimedia computer (movies, simple games), you can add a small SSD drive in addition to the HDD, which will make the system work much faster and more responsive. As a compromise between speed and capacity, you can consider installing one SSHD drive, which will be much cheaper.

For a powerful gaming or professional computer, the best option is to install two drives - an SSD for the operating system, programs, games, and a regular hard drive for storing user files.

4. Physical sizes of disks

Hard drives for desktop computers are 3.5 inches in size.

Solid state drives are 2.5 inches in size, just like laptop hard drives.

An SSD drive is installed into a regular computer using a special mount in the case or an additional adapter.

Don't forget to purchase it if it is not included with the drive and your case does not have special mounts for 2.5″ drives. But now almost all modern cases have mounts for SSD drives, which are indicated in the description as internal 2.5″ bays.

5. Hard drive connectors

All hard drives have an interface connector and a power connector.

5.1. Interface connector

An interface connector is a connector for connecting a drive to the motherboard using a special cable (cable).

Modern hard drives (HDD) have a SATA3 connector, which is fully compatible with older versions of SATA2 and SATA1. If your motherboard has old connectors, don't worry, a new hard drive can be connected to them and it will work.

But for an SSD drive, it is desirable that the motherboard have SATA3 connectors. If your motherboard has SATA2 connectors, then the SSD drive will operate at half its speed (about 280 MB/s), which, however, is still significantly faster than a regular HDD.

5.2. Power connector

Modern hard drives (HDD) and solid-state drives (SSD) have the same 15-pin SATA power connectors. If the disk is installed in a desktop computer, its power supply must have such a connector. If it is not there, then you can use a Molex-SATA power adapter.

6. Hard drive capacities

For each type of hard drive, depending on its purpose, the amount of data it can hold will be different.

6.1. Hard disk capacity (HDD) for a computer

For a computer intended for typing and accessing the Internet, the smallest modern hard drive – 320-500 GB – is sufficient.

For a multimedia computer (video, music, photos, simple games), it is advisable to have a hard drive with a capacity of 1000 GB (1 TB).

A powerful gaming or professional computer may require a 2-4 TB drive (use your needs).

It is necessary to take into account that the computer’s motherboard must support UEFI, otherwise the operating system will not see the entire disk capacity of more than 2 TB.

If you want to increase the speed of the system, but are not ready to spend money on an additional SSD drive, then as an alternative option you can consider purchasing a hybrid SSHD drive with a capacity of 1-2 TB.

6.2. Hard disk capacity (HDD) for a laptop

If a laptop is used as an addition to the main computer, then a hard drive with a capacity of 320-500 GB will be sufficient. If a laptop is used as a main computer, then it may require a hard drive with a capacity of 750-1000 GB (depending on the use of the laptop).
Hard drive Hitachi Travelstar Z5K500 HTS545050A7E680 500GB

You can also install an SSD drive in the laptop, which will significantly increase its speed and system responsiveness, or a hybrid SSHD drive, which is slightly faster than a regular HDD.
Hard drive Seagate Laptop SSHD ST500LM021 500GB

It is important to consider what thickness of disks your laptop supports. Discs with a thickness of 7 mm will fit into any model, but those with a thickness of 9 mm may not fit everywhere, although not many of them are produced anymore.

6.3. Solid State Drive (SSD) Capacity

Since SSD drives are not used for storing data, when determining their required capacity, you need to proceed from how much space the operating system installed on it will take up and whether you will install any other large programs and games on it.

Modern operating systems (Windows 7,8,10) require about 40 GB of space to operate and grow with updates. In addition, you need to install at least the basic programs on the SSD, otherwise it won’t be of much use. Well, for normal operation, there should always be 15-30% free space on the SSD.

For a multimedia computer (movies, simple games), the best option would be an SSD with a capacity of 120-128 GB, which will allow, in addition to the system and basic programs, to install several simple games on it. Since an SSD is required not only to quickly open folders, it makes sense to install the most powerful programs and games on it, which will speed up their operation.

Heavy modern games take up a huge amount of space. Therefore, a powerful gaming computer requires a 240-512 GB SSD, depending on your budget.

For professional tasks, such as editing video in high quality, or installing a dozen modern games, you need an SSD with a capacity of 480-1024 GB, again depending on the budget.

6.4. Data backup

When choosing disk space, it is advisable to also take into account the need to create a backup copy of user files (videos, photos, etc.) that will be stored on it. Otherwise, you risk instantly losing everything you have accumulated over the years. Therefore, it is often more advisable to purchase not one huge disk, but two smaller disks - one for work, the other (possibly external) for a backup copy of files.

7. Basic disk parameters

The main parameters of disks, which are often indicated in price lists, include spindle speed and memory buffer size.

7.1. Spindle speed

The spindle has hard and hybrid disks based on magnetic platters (HDD, SSHD). Since SSD drives are built on memory chips, they do not have a spindle. The speed of the hard drive's spindle determines its operating speed.

The spindle of hard drives for desktop computers generally has a rotation speed of 7200 rpm. Sometimes there are models with a spindle speed of 5400 rpm, which work slower.

Laptop hard drives generally have a spindle speed of 5400 rpm, which allows them to be quieter, run cooler, and consume less power.

7.2. Memory Buffer Size

A buffer is a cache memory of a hard drive based on memory chips. This buffer is intended to speed up the hard drive, but it does not have a big impact (about 5-10%).

Modern hard drives (HDD) have a buffer size of 32-128 MB. In principle, 32 MB is enough, but if the price difference is not significant, then you can take a hard drive with a larger buffer size. Optimal for today is 64 MB.

8. Disk speed characteristics

Speed ​​characteristics common to HDD, SSHD and SSD drives include linear read/write speed and random access time.

8.1. Linear reading speed

Linear read speed is the main parameter for any disk and dramatically affects its operating speed.

For modern hard drives and hybrid drives (HDD, SSHD), an average read speed of closer to 150 MB/s is a good value. You should not purchase hard drives with a speed of 100 MB/s or less.

Solid state drives (SSD) are much faster and their read speed, depending on the model, is 160-560 MB/s. The optimal price/speed ratio is SSD drives with a read speed of 450-500 MB/s.

As for HDD drives, sellers in price lists usually do not indicate their speed parameters, but only the volume. Later in this article I will tell you how to find out these characteristics. With SSD drives everything is simpler, since their speed characteristics are always indicated in the price lists.

8.2. Linear write speed

This is a secondary parameter after reading speed, which is usually indicated in tandem with it. For hard and hybrid drives (HDD, SSHD), the write speed is usually somewhat lower than the read speed and is not considered when choosing a disk, since they are mainly focused on the read speed.

For SSD drives, the write speed can be either less than or equal to the read speed. In price lists, these parameters are indicated through a slash (for example, 510/430), where a larger number means read speed, a smaller number means write speed.

For good fast SSDs it is about 550/550 MB/s. But in general, write speed has a much smaller effect on the speed of a computer than read speed. As a budget option, a slightly lower speed is allowed, but not lower than 450/350 Mb/s.

8.3. Access time

Access time is the second most important disk parameter after read/write speed. Access time has a particularly strong effect on the speed of reading/copying small files. The lower this parameter, the better. In addition, low access time indirectly indicates a higher quality hard disk drive (HDD).

A good access time for a hard disk drive (HDD) is 13-15 milliseconds. Values ​​within 16-20 ms are considered a bad indicator. I will also tell you how to determine this parameter in this article.

As for SSD drives, their access time is 100 times less than that of HDD drives, so this parameter is not indicated anywhere and is not paid attention to.

Hybrid disks (SSHD), due to additional built-in flash memory, achieve lower access times than HDDs, which are comparable to SSDs. But due to the limited capacity of flash memory, lower access times are only achieved when accessing the most frequently accessed files that end up in that flash memory. Usually these are system files, which provide higher computer boot speed and high system responsiveness, but do not fundamentally affect the operation of large programs and games, since they simply will not fit in the limited amount of fast memory of an SSHD disk.

9. Manufacturers of hard drives (HDD, SSHD)

The most popular hard drive manufacturers are the following:

Seagate- produces some of the fastest drives today, but they are not considered the most reliable.

Western Digital (WD)— are considered the most reliable and have a convenient classification by color.

• WD Blue– budget general purpose drives
• W.D. Green– quiet and economical (frequently switched off)
• WD Black– fast and reliable
• WD Red– for data storage systems (NAS)
• WD Purple– for video surveillance systems
• W.D. Gold– for servers
• W.D. Re– for RAID arrays
• W.D.Se– for scalable corporate systems

Blue are the most common drives, suitable for inexpensive office and multimedia PCs. Black ones combine high speed and reliability; I recommend using them in powerful systems. The rest are intended for specific tasks.

In general, if you want cheaper and faster, then choose Seagate. If it's cheap and reliable - Hitachi. Fast and reliable - Western Digital from the black series.

Hybrid SSHD drives are now mainly produced by Seagete and they are of good quality.

There are discs from other manufacturers on sale, but I recommend limiting yourself to the indicated brands, as there are fewer problems with them.

10. Manufacturers of solid state drives (SSD)

Among the manufacturers of SSD drives, the following have proven themselves well:

• Samsung
• Intel
• Crucial
• SanDisk
• Plextor

More budget options can be considered:

• Corsair
• GoodRAM
• A-DATA (Premier Pro)
• Kingston (HyperX)

11. SSD memory type

SSD drives can be built on different types of memory:

• 3 D NAND– fast and durable
• MLC– good resource
• V-NAND– average resource
• TLC– low resource

12. Hard drive speed (HDD, SSHD)

We can find out all the parameters of SSD drives we need, such as capacity, speed and manufacturer, from the seller’s price list and then compare them by price.

The parameters of HDD drives can be found out by the model or batch number on the manufacturers' websites, but in fact this is quite difficult, since these catalogs are huge, have a lot of incomprehensible parameters, which are called differently for each manufacturer, and also in English. Therefore, I offer you another method that I use myself.

There is a program for testing hard drives HDTune. It allows you to determine parameters such as linear reading speed and access time. There are many enthusiasts who conduct these tests and post the results on the Internet. In order to find the test results of a particular hard drive model, just enter its model number in the Google or Yandex image search, which is indicated in the seller’s price list or on the drive itself in the store.

This is what the disk test image from the search looks like.

As you can see, this picture shows the average linear read speed and random access time, which are what interests us. Just make sure that the model number in the picture matches the model number of your drive.

In addition, the graph can be used to roughly determine the quality of the disc. An uneven graph with large jumps and high access times indirectly indicate imprecise, low-quality disk mechanics.

A beautiful cyclical or simply uniform graph without large jumps, combined with low access time, indicates precise, high-quality disk mechanics.

Such a disk will work better, faster and last longer.

13. Optimal disk

So, which disk or disk configuration to choose for your computer, depending on its purpose. In my opinion, the following configurations will be the most optimal.

• office PC – HDD (320-500 GB)
• entry-level multimedia PC – HDD (1 TB)
• mid-level multimedia PC – SSD (120-128 GB) + HDD (1 TB) or SSHD (1 TB)
• Entry-level gaming PC – HDD (1 TB)
• Mid-range gaming PC – SSHD (1 TB)
• High-end gaming PC – SSD (240-512 GB) + HDD (1-2 TB)
• professional PC – SSD (480-1024 GB) + HDD/SSHD (2-4 TB)

14. Cost of HDD and SSD drives

In conclusion, I want to talk a little about the general principles of choosing between more or less expensive disk models.

The price of HDD disks depends most on the disk capacity and slightly on the manufacturer (by 5-10%). Therefore, it is not advisable to skimp on the quality of HDDs. Buy models from recommended manufacturers, even if they are a little more expensive, as they will last longer.

The price of SSD drives, in addition to capacity and speed, also greatly depends on the manufacturer. Here I can give a simple recommendation - choose the cheapest SSD drive from the list of recommended manufacturers that suits you in terms of capacity and speed.

15. Links

Hard drive Western Digital Black WD1003FZEX 1TB
Hard drive Western Digital Caviar Blue WD10EZEX 1 TB
Hard drive A-Data Ultimate SU650 120GB

Many of you know that all information on a computer, presented in the form of files and folders, is stored on the hard drive. And here, what is a hard drive and what it is intended for, not many will answer correctly. It is very difficult for people far from programming to imagine how information can be stored on some piece of hardware. This is not a box or a piece of paper on which this very information can be written down and hidden in the box. Yes, a hard drive is not a box with a letter.

A hard disk (HDD, HMDD - from the English hard (magnetic) disk drive) is a magnetic storage medium. In computer slang it is called a “Winchester”. It is designed to store information in the form of photographs, pictures, letters, books of various formats, music, films, etc. Externally, this device does not look like a disk at all. Rather, it looks like a small rectangular iron box.

The internals of a hard drive are similar to an old vinyl record player.

Inside this metal box there are round aluminum or glass plates-disks, located on the same axis, along which the reading head moves. Unlike a player, the hard disk head does not touch the surface of the platters during operation.

For ease of use, the hard drive is divided into several sections. This division is conditional. This is done using the operating system or special programs. The new partitions are called logical disks. They are assigned the letters C, D, E or F. Usually installed on the C drive, and files and folders are stored on other drives so that if the system crashes, your files and folders are not damaged.

Watch a video about what a hard drive is:

Basic characteristics of hard drives

• Form factor is the width of the hard drive in inches. The standard size for a desktop computer is 3.5 inches, and for laptops it is 2.5 inches;
• Interface– modern computers use different versions of SATA connections to the motherboard. SATA, SATA II, SATA III. Older computers use the IDE interface.
• Capacity– this is the maximum amount of information that a hard drive can store, measured in gigabytes;
• Spindle speed is the number of spindle revolutions per minute. The higher the disk rotation speed, the better. For operating systems, you need to install disks of 7,200 rpm and higher, and for storing files you can install disks with lower speeds.
• MTBF– this is the average time between failures calculated by the manufacturer. The larger it is, the better;
• Random access time is the average time required for the head to position itself on an arbitrary section of the plate. The value is not constant.
• Impact resistance is the ability of a hard drive to withstand pressure changes and shocks.
• Noise level, which the disk emits during operation is measured in decibels. The smaller it is, the better.

Now there are already SSD drives (solid-state drive in simple translation - solid-state drive), which have neither a spindle nor platters. It is a storage device based on memory chips.

SSD drives are completely silent and have very good read and write speeds. But they are still very expensive and not very reliable, so they are installed only for operating systems, and IDE and SATA hard drives are used to store files.

A modern hard drive is a unique computer component. It is unique in that it stores service information, by studying which you can assess the “health” of the disk. This information contains the history of changes in many parameters monitored by the hard drive during operation. No longer does any component of the system unit provide the owner with statistics of its operation! Coupled with the fact that the HDD is one of the most unreliable components of a computer, such statistics can be very useful and help its owner avoid hassle and loss of money and time.

Information about the status of the disk is available thanks to a set of technologies collectively called S.M.A.R.T. (Self-Monitoring, Analisys and Reporting Technology, i.e. technology of self-monitoring, analysis and reporting). This complex is quite extensive, but we will talk about those aspects of it that allow you to look at the S.M.A.R.T. attributes displayed in any hard drive testing program and understand what is going on with the disk.

I note that the following applies to drives with SATA and PATA interfaces. SAS, SCSI and other server drives also have S.M.A.R.T., but its presentation is very different from SATA/PATA. And it’s usually not a person who monitors server disks, but a RAID controller, so we won’t talk about them.

So, if we open S.M.A.R.T. in any of the numerous programs, we will see approximately the following picture (the screenshot shows the S.M.A.R.T. of the Hitachi Deskstar 7K1000.C HDS721010CLA332 disk in HDDScan 3.3):

Each line displays a different S.M.A.R.T attribute. Attributes have more or less standardized names and a specific number, which do not depend on the model and manufacturer of the disk.

Each S.M.A.R.T. attribute has several fields. Each field belongs to a specific class from the following: ID, Value, Worst, Threshold and RAW. Let's look at each of the classes.

• ID(may also be called Number) - identifier, attribute number in S.M.A.R.T technology. The name of the same attribute can be given differently by programs, but the identifier always uniquely identifies the attribute. This is especially useful in the case of programs that translate the generally accepted attribute name from English into Russian. Sometimes the result is such nonsense that you can understand what kind of parameter it is only by its identifier.
• Value (Current)— the current value of the attribute in parrots (i.e., in values ​​of unknown dimension). During the operation of the hard drive, it can decrease, increase and remain unchanged. Using the Value indicator, you cannot judge the “health” of an attribute without comparing it with the Threshold value of the same attribute. As a rule, the smaller the Value, the worse the state of the attribute (initially all value classes except RAW on the new disk have the maximum possible value, for example 100).
• Worst— the worst value that Value reached in the entire life of the hard drive. It is also measured in “parrots”. During operation, it may decrease or remain unchanged. It is also impossible to clearly judge the health of an attribute; you need to compare it with Threshold.
• Threshold— the value in “parrots” that the Value of the same attribute must reach in order for the attribute’s state to be considered critical. Simply put, Threshold is a threshold: if Value is greater than Threshold, the attribute is OK; if less or equal - with the problem attribute. It is according to this criterion that utilities that read S.M.A.R.T. issue a report on the state of the disk or an individual attribute like “Good” or “Bad”. At the same time, they do not take into account that even with a Value greater than Threshold, the disk may in fact already be dying from the user’s point of view, or even a walking dead man, so when assessing the health of a disk, it is still worth looking at another attribute class, and namely RAW. However, it is the Value value that has dropped below Threshold that can become a legitimate reason for replacing the disk under warranty (for the warranty providers themselves, of course) - who can speak more clearly about the health of the disk than himself, demonstrating the current attribute value is worse than the critical threshold? That is, with a Value value greater than Threshold, the disk itself considers that the attribute is healthy, and with a value less than or equal to it, that it is sick. Obviously, if Threshold=0, the attribute state will never be considered critical. Threshold is a constant parameter hardcoded into the disk by the manufacturer.
• RAW (Data)- the most interesting, important and necessary indicator for evaluation. In most cases, it does not contain “parrots”, but real values ​​expressed in various units of measurement, directly indicating the current state of the disk. Based on this indicator, the Value value is formed (but by what algorithm it is formed is already a secret of the manufacturer, shrouded in darkness). It is the ability to read and analyze the RAW field that makes it possible to objectively assess the condition of the hard drive.

This is what we will do now - we will analyze all the most used S.M.A.R.T. attributes, see what they say and what needs to be done if they are not in order.

Attributes S.M.A.R.T.

0x

0x

Before describing the attributes and acceptable values ​​of their RAW field, I will clarify that attributes can have a RAW field of different types: current and accumulating. The current field contains the value of the attribute at the moment, it is characterized by periodic changes (for some attributes - occasionally, for others - many times per second; another thing is that such rapid changes are not displayed in S.M.A.R.T. readers). Accumulation field - contains statistics, usually it contains the number of occurrences of a particular event since the disk was first started.

The current type is typical for attributes for which there is no point in summing their previous readings. For example, the disk temperature display is current: its purpose is to show the current temperature, not the sum of all previous temperatures. The accumulating type is characteristic of attributes for which their whole purpose is to provide information over the entire “life” of the hard drive. For example, an attribute characterizing the operating time of a disk is cumulative, i.e., it contains the number of units of time worked by the drive over its entire history.

Let's start looking at attributes and their RAW fields.

Attribute: 01 Raw Read Error Rate

All Seagate, Samsung (starting with the SpinPoint F1 family (inclusive)) and Fujitsu 2.5″ drives have huge numbers in these fields.

For other Samsung drives and all WD drives, this field is set to 0.

For Hitachi disks, this field is characterized by 0 or periodic changes in the field ranging from 0 to several units.

Such differences are due to the fact that all Seagate hard drives, some Samsung and Fujitsu consider the values ​​of these parameters differently than WD, Hitachi and other Samsung. When any hard drive operates, errors of this kind always arise, and it overcomes them on its own, this is normal, it’s just that on disks that contain 0 or a small number in this field, the manufacturer did not consider it necessary to indicate the true number of these errors.

Thus, a non-zero parameter on WD and Samsung drives up to SpinPoint F1 (not inclusive) and a large parameter value on Hitachi drives may indicate hardware problems with the drive. Note that utilities may display multiple values ​​contained in the RAW field of this attribute as one, and it will appear quite large, although this will not be correct (see below for details).

On Seagate, Samsung (SpinPoint F1 and newer) and Fujitsu drives, you can ignore this attribute.

Attribute: 02 Throughput Performance

The parameter does not provide any information to the user and does not indicate any danger for any of its values.

Attribute: 03 Spin-Up Time

The acceleration time may vary for different disks (and for disks from the same manufacturer too) depending on the spin-up current, the weight of the plates, the rated spindle speed, etc.

By the way, Fujitsu hard drives always have a one in this field if there are no problems with spindle spinning.

It says practically nothing about the health of the disk, so when assessing the condition of the hard drive, you can ignore this parameter.

Attribute: 04 Number of Spin-Up Times (Start/Stop Count)

When assessing health, ignore the attribute.

Attribute: 05 Reallocated Sector Count

Let us explain what a “reassigned sector” actually is. When a disk encounters an unreadable/hard-to-read/unwritable/hard-to-write sector during operation, it may consider it irreparably damaged. Especially for such cases, the manufacturer provides a reserve area on each disk (on some models - in the center (logical end) of the disk, on some - at the end of each track, etc.). If there is a damaged sector, the disk marks it as unreadable and uses the sector in the spare area instead, making the appropriate notes in a special list of surface defects - G-list. This operation of assigning a new sector to the role of an old one is called remap or reassignment, and the sector used instead of the damaged one is reassigned. The new sector receives the logical LBA number of the old one, and now when software accesses a sector with this number (programs do not know about any reassignments!) the request will be redirected to the reserve area.

Thus, even though the sector has failed, the disk capacity does not change. It is clear that it does not change for the time being, since the volume of the reserve area is not infinite. However, the spare area may well contain several thousand sectors, and allowing it to run out would be very irresponsible - the disk will need to be replaced long before that.

By the way, repairmen say that Samsung drives very often do not want to perform sector reassignment.

Opinions vary regarding this attribute. Personally, I think that if it reaches 10, the disk must be changed - after all, this means a progressive process of degradation of the state of the surface of either pancakes, or heads, or something else hardware, and there is no way to stop this process. By the way, according to people close to Hitachi, Hitachi itself considers a disk to be replaced when it already has 5 reassigned sectors. Another question is whether this information is official, and whether service centers follow this opinion. Something tells me no :)

Another thing is that service center employees may refuse to recognize the disk as faulty if the disk manufacturer’s proprietary utility writes something like “S.M.A.R.T. Status: Good" or the values ​​of the Value or Worst attribute will be greater than Threshold (in fact, the manufacturer’s utility itself can evaluate by this criterion). And formally they will be right. But who needs a disk with constant deterioration of its hardware components, even if such deterioration is consistent with the nature of the hard drive, and hard drive technology tries to minimize its consequences by allocating, for example, a spare area?

Attribute: 07 Seek Error Rate

The description of the formation of this attribute almost completely coincides with the description for attribute 01 Raw Read Error Rate, with the exception that for Hitachi hard drives the normal value of the RAW field is only 0.

Thus, do not pay attention to the attribute on Seagate, Samsung SpinPoint F1 and newer and Fujitsu 2.5″ drives; on other Samsung models, as well as on all WD and Hitachi drives, a non-zero value indicates problems, for example, with a bearing, etc. .

Attribute: 08 Seek Time Performance

It does not provide any information to the user and does not indicate any danger regardless of its value.

Attribute: 09 Power On Hours Count (Power-on Time)

Doesn't say anything about the health of the drive.

Attribute: 10 (0A - hexadecimal) Spin Retry Count

Most often it does not indicate the health of the disk.

The main reasons for increasing the parameter are poor contact of the disk with the power supply or the inability of the power supply to supply the required current to the power line of the disk.

Ideally, it should be equal to 0. If the attribute value is 1-2, you can ignore it. If the value is higher, first of all you should pay close attention to the condition of the power supply, its quality, the load on it, check the contact of the hard drive with the power cable, check the power cable itself.

Surely the disk may not start immediately due to problems with itself, but this happens very rarely, and this possibility should be considered last.

Attribute: 11 (0B) Calibration Retry Count (Recalibration Retries)

A non-zero, or especially a growing value of the parameter may indicate problems with the disk.

Attribute: 12 (0C) Power Cycle Count

Not related to the disk state.

Attribute: 183 (B7) SATA Downshift Error Count

Does not indicate the health of the drive.

Attribute: 184 (B8) End-to-End Error

A non-zero value indicates disk problems.

Attribute: 187 (BB) Reported Uncorrected Sector Count (UNC Error)

A non-zero attribute value clearly indicates that the disk state is abnormal (in combination with a non-zero attribute value of 197) or that it previously was (in combination with a zero attribute value of 197).

Attribute: 188 (BC) Command Timeout

Such errors can occur due to poor quality cables, contacts, adapters used, extension cords, etc., as well as due to the incompatibility of the drive with a specific SATA/PATA controller on the motherboard (or a discrete one). Due to errors of this kind, BSODs are possible in Windows.

A non-zero attribute value indicates a potential disk disease.

Attribute: 189 (BD) High Fly Writes

In order to say why such cases occur, you need to be able to analyze S.M.A.R.T. logs, which contain information specific to each manufacturer, which is not currently implemented in publicly available software - therefore, the attribute can be ignored.

Attribute: 190 (BE) Airflow Temperature

Does not indicate the condition of the disk.

Attribute: 191 (BF) G-Sensor Shock Count (Mechanical Shock)

Relevant for mobile hard drives. On Samsung disks you can often ignore this, because they may have a very sensitive sensor that, figuratively speaking, almost reacts to the movement of air from the wings of a fly flying in the same room as the disk.

In general, the activation of the sensor is not a sign of an impact. It can even grow from positioning the BMG with the disk itself, especially if it is not secured. The main purpose of the sensor is to stop the recording operation when there is vibration to avoid errors.

Doesn't indicate disk health.

Attribute: 192 (C0) Power Off Retract Count (Emergency Retry Count)

Does not allow you to judge the condition of the disk.

Attribute: 193 (C1) Load/Unload Cycle Count

Doesn't indicate disk health.

Attribute: 194 (C2) Temperature (HDA Temperature, HDD Temperature)

The attribute does not indicate the state of the disk, but allows you to control one of the most important parameters. My opinion: when working, try not to allow the temperature of the hard drive to rise above 50 degrees, although the manufacturer usually declares a maximum temperature limit of 55-60 degrees.

Attribute: 195 (C3) Hardware ECC Recovered

The features inherent in this attribute on different disks fully correspond to those of attributes 01 and 07.

Attribute: 196 (C4) Reallocated Event Count

Indirectly speaks about the health of the disk. The higher the value, the worse. However, it is impossible to unambiguously judge the health of a disk based on this parameter without considering other attributes.

This attribute is directly related to attribute 05. When 196 grows, 05 most often grows as well. If when attribute 196 grows, attribute 05 does not grow, it means that when trying to remap, the candidate for bad blocks turned out to be a soft bad (see details below), and the disk corrected it so that the sector was considered healthy and no reassignment was necessary.

If attribute 196 is less than attribute 05, it means that during some remapping operations, several bad sectors were transferred in one go.

If attribute 196 is greater than attribute 05, it means that during some reassignment operations, soft bads were discovered that were subsequently corrected.

Attribute: 197 (C5) Current Pending Sector Count

When encountering a “bad” sector during operation (for example, the sector checksum does not match the data in it), the disk marks it as a candidate for reassignment, adds it to a special internal list and increases parameter 197. It follows that the disk may have damaged sectors, which he does not yet know about - after all, there may well be areas on the plates that the hard drive does not use for some time.

When attempting to write to a sector, the disk first checks to see if the sector is on the candidate list. If the sector is not found there, recording proceeds as usual. If found, this sector is tested by writing and reading. If all test operations pass normally, then the disk considers the sector to be healthy. (That is, there was a so-called “soft bad” - the erroneous sector arose not due to the fault of the disk, but for other reasons: for example, at the time of recording the information, the electricity went out, and the disk interrupted the recording, parking the BMG. As a result, the data in sector will be unwritten, and the sector checksum, which depends on the data in it, will generally remain old. There will be a discrepancy between it and the data in the sector.) In this case, the disk performs the originally requested write and removes the sector from the list of candidates. In this case, attribute 197 is reduced, and attribute 196 can also be increased.

If testing fails, the disk performs a reassignment operation, decreasing attribute 197, increasing 196 and 05, and also makes notes in the G-list.

So, a non-zero value of the parameter indicates a problem (however, it cannot indicate whether the problem is with the disk itself).

If the value is non-zero, you must start sequential reading of the entire surface in the Victoria or MHDD programs with the option remap. Then, when scanning, the disk will definitely come across a bad sector and try to write to it (in the case of Victoria 3.5 and the option Advanced remap— the disk will try to write the sector up to 10 times). Thus, the program will trigger the “treatment” of the sector, and as a result the sector will either be fixed or reassigned.

If reading fails, both with remap, so with Advanced remap, it’s worth trying to run sequential recording in the same Victoria or MHDD. Keep in mind that the write operation erases data, so be sure to make a backup before using it!

Sometimes the following manipulations can help prevent a remap from being performed: remove the disk electronics board and clean the hard drive contacts connecting it to the board - they may be oxidized. Be careful when performing this procedure - it may void your warranty!

The impossibility of a remap may be due to another reason - the disk has exhausted the reserve area, and it simply has nowhere to reassign sectors.

If the value of attribute 197 is not reduced to 0 by any manipulation, you should think about replacing the disk.

Attribute: 198 (C6) Offline Uncorrectable Sector Count (Uncorrectable Sector Count)

This parameter changes only under the influence of offline testing; no scanning programs affect it. For operations during self-test, the behavior of the attribute is the same as attribute 197.

A non-zero value indicates problems with the disk (just like 197, without specifying who is to blame).

Attribute: 199 (C7) UltraDMA CRC Error Count

In the vast majority of cases, the causes of errors are a poor-quality data transfer cable, overclocking of the PCI/PCI-E buses of the computer, or poor contact in the SATA connector on the disk or on the motherboard/controller.

Errors during transmission over the interface and, as a result, an increasing value of the attribute can lead to the operating system switching the operating mode of the channel on which the drive is located to PIO mode, which entails a sharp drop in the read/write speed when working with it and processor load to 100% (visible in Windows Task Manager).

In the case of Hitachi hard drives of the Deskstar 7K3000 and 5K3000 series, a growing attribute may indicate incompatibility between the disk and the SATA controller. To correct the situation, you need to force the drive to switch to SATA 3 Gb/s mode.

My opinion: if there are errors, reconnect the cable at both ends; if their number grows and it is more than 10, throw away the cable and replace it with a new one or remove the overclock.

Attribute: 200 (C8) Write Error Rate (MultiZone Error Rate)

Attribute: 202 (CA) Data Address Mark Error

Attribute: 203 (CB) Run Out Cancel

The health effects are unknown.

Attribute: 220 (DC) Disk Shift

The health effects are unknown.

Attribute: 240 (F0) Head Flying Hours

The health effects are unknown.

Attribute: 254 (FE) Free Fall Event Count

The health effects are unknown.

Let us summarize the description of the attributes. Non-zero values:

When analyzing attributes, be aware that some S.M.A.R.T. Several values ​​of this parameter can be stored: for example, for the penultimate startup of the disk and for the last one. Such multi-byte parameters are logically composed of multiple values ​​that are smaller in number of bytes - for example, a parameter that stores two values ​​for the last two runs, each with 2 bytes allocated, would be 4 bytes long. Programs that interpret S.M.A.R.T. are often unaware of this, and show this parameter as one number rather than two, which sometimes leads to confusion and anxiety for the owner of the disk. For example, "Raw Read Error Rate" storing the penultimate value of "1" and the last value of "0" would look like 65536.

It should be noted that not all programs can display such attributes correctly. Many people translate an attribute with several values ​​into the decimal number system as one huge number. The correct way to display such content is either with a breakdown by value (then the attribute will consist of several separate numbers), or in a hexadecimal number system (then the attribute will look like one number, but its components will be easily distinguishable at first glance), or both , and something else at the same time. Examples of correct programs are HDDScan, CrystalDiskInfo, Hard Disk Sentinel.

Let's demonstrate the differences in practice. This is what the instantaneous value of attribute 01 looks like on one of my Hitachi HDS721010CLA332 without taking into account the Victoria 4.46b feature of this attribute:

And this is what it looks like in the “correct” HDDScan 3.3:

The advantages of HDDScan in this context are obvious, aren’t they?

If you analyze S.M.A.R.T. on different disks, you may notice that the same attributes may behave differently. For example, some S.M.A.R.T. parameters Hitachi hard drives are reset to zero after a certain period of disk inactivity; parameter 01 has features on Hitachi, Seagate, Samsung and Fujitsu drives, 03 - on Fujitsu. It is also known that after flashing the disk, some parameters may be set to 0 (for example, 199). However, such forced resetting of the attribute will in no way mean that the problems with the disk have been resolved (if any). After all, a growing critical attribute is consequence problems, not cause.

When analyzing multiple datasets, S.M.A.R.T. It becomes obvious that the set of attributes for disks from different manufacturers and even for different models of the same manufacturer may differ. This is due to the so-called vendor specific attributes (i.e., attributes used to monitor their disks by a specific manufacturer) and should not be a cause for concern. If monitoring software can read such attributes (for example, Victoria 4.46b), then on disks for which they are not intended, they can have “terrible” (huge) values, and you simply do not need to pay attention to them. This is how, for example, Victoria 4.46b displays RAW values ​​of attributes that are not intended for monitoring on the Hitachi HDS721010CLA332:

There is often a problem when programs cannot calculate S.M.A.R.T. disk. In the case of a working hard drive, this can be caused by several factors. For example, very often S.M.A.R.T. is not displayed. when connecting a disk in AHCI mode. In such cases, it is worth trying different programs, in particular HDD Scan, which has the ability to work in this mode, although it does not always succeed, or it is worth temporarily switching the disk to IDE compatibility mode, if possible. Further, on many motherboards, the controllers to which the hard drives are connected are not built into the chipset or south bridge, but are implemented on separate chips. In this case, the DOS version of Victoria, for example, will not see the hard drive connected to the controller, and it will need to force it to be specified by pressing the [P] key and entering the number of the channel with the disk. S.M.A.R.T.s are often not read. for USB drives, which is explained by the fact that the USB controller simply does not pass commands to read S.M.A.R.T. Almost never read S.M.A.R.T. for disks operating as part of a RAID array. Here, too, it makes sense to try different programs, but in the case of hardware RAID controllers this is useless.

If, after purchasing and installing a new hard drive, any programs (HDD Life, Hard Drive Inspector and others like them) show that: the disk has 2 hours left to live; its productivity is 27%; health - 19.155% (select according to your taste) - then there is no need to panic. Understand this. Firstly, you need to look at the S.M.A.R.T. indicators, and not at the health and productivity numbers that came from nowhere (however, the principle of their calculation is clear: the worst indicator is taken). Secondly, any program when assessing S.M.A.R.T. parameters. looks at the deviation of the values ​​of various attributes from previous readings. When you first launch a new disk, the parameters are not constant; it takes some time to stabilize them. The program that evaluates S.M.A.R.T. sees that the attributes are changing, makes calculations, it turns out that if they change at this rate, the drive will soon fail, and it begins to signal: “Save the data!” Some time will pass (up to a couple of months), the attributes will stabilize (if everything is really in order with the disk), the utility will collect data for statistics, and the timing of the death of the disk as S.M.A.R.T. stabilizes. will be transported further and further into the future. Evaluation of Seagate and Samsung drives by programs is a completely different matter. Due to the peculiarities of attributes 1, 7, 195, programs, even for an absolutely healthy disk, usually give the conclusion that it is wrapped in a sheet and crawling to the cemetery.

Please note that the following situation is possible: all S.M.A.R.T. attributes. - normal, but in fact the disk has problems, although this is not noticeable in anything yet. This is explained by the fact that S.M.A.R.T technology. It works only “after the fact”, i.e. the attributes change only when the disk encounters problem areas during operation. And until he comes across them, he doesn’t know about them and, therefore, in S.M.A.R.T. he has nothing to record.

So S.M.A.R.T. is a useful technology, but it must be used wisely. Additionally, even if S.M.A.R.T. your disk is perfect, and you constantly check the disk - do not rely on the fact that your disk will “live” for many years to come. Winchesters tend to break so quickly that S.M.A.R.T. it simply does not have time to display its changed state, and it also happens that there are obvious problems with the disk, but in S.M.A.R.T. - Everything is fine. You could say that a good S.M.A.R.T. does not guarantee that everything is fine with the drive, but bad S.M.A.R.T. guaranteed to indicate problems. Moreover, even with bad S.M.A.R.T. utilities may indicate that the disk status is “healthy” due to the fact that critical attributes have not reached threshold values. Therefore, it is very important to analyze S.M.A.R.T. yourself, without relying on “verbal” evaluation of programs.

Although S.M.A.R.T. technology and it works, hard drives and the concept of “reliability” are so incompatible that they are considered simply consumables. Well, like cartridges in a printer. Therefore, to avoid losing valuable data, make periodic backups of it to another medium (for example, another hard drive). It is optimal to make two backup copies on two different media, not counting the hard drive with the original data. Yes, this leads to additional costs, but believe me: the cost of restoring information from a broken HDD will cost you many times - if not an order of magnitude - more. But data cannot always be restored even by professionals. That is, the only way to ensure reliable storage of your data is to backup it.

Finally, I will mention some programs that are well suited for S.M.A.R.T analysis. and hard drive testing: HDDScan (Windows, DOS, free), MHDD (DOS, free).