What is a hard drive? Characteristics of hard drives. Computer hard drive. Everything about him
Computer hard drive is a place for long-term storage of information. In the computer specifications it is designated as HDD. Hard Disk Drive). In computer slang it is called a “hard drive” or “screw”. You can also hear the name “hard”. It received the name “Winchester” by analogy with the popular Winchester carbine, which used the “30-30 Winchester” cartridge. First hard drive for a personal computer was laid out into 30 tracks, each of which had 30 sectors, hence the name “hard drive”. A hard drive is a non-volatile component in a computer, i.e. When the power is turned off, the recorded (saved) data is not erased.
Hard drive device.
Data is stored on one or more aluminum or glass circular plates (disks) coated with a magnetic layer. The disk(s) are on a spindle and rotate at high speed, and a block of movable magnetic heads reads or writes data to the surface of the platters.
The disk(s) with the head unit are enclosed in a metal case to protect them from dust and mechanical influences. On the case there is an electronic board that controls the operation of the hard drive - the so-called controller. This entire device represents single block, which is located in a specially designated place “” and connected to the motherboard with a special cable.
Basic characteristics of the hard drive.
Let's look at the main characteristics hard drive things you need to know.
VolumeHDD. Probably the most important characteristic, which determines the maximum possible volume for storing information. Denoted in gigabytes (GB) and terabytes (TB). Modern hard drives have a capacity from 320 GB to 4 TB.
How can a novice user decide how much HDD capacity he needs? When choosing a computer, you should base your needs on it. If only for office use (text typing, printing, Internet, photo storage and processing...), then a hard drive with a capacity of 320-500 GB is sufficient. For games, watching movies, listening to music, you need a larger volume - from 500 GB to the maximum. A Blu-Ray movie can take up to 45 GB, and modern games are becoming more and more voracious, for example GTA 5 requires 65 GB of disk space.
Rotation speed. Another important characteristic that affects the performance of a hard drive. The faster the plates rotate, the faster access and recording data on them. The rotation speed is measured in revolutions per minute (rpm or rpm from the English rotate per minute). For use in personal computers Hard drives with 5400 rpm and 7200 rpm are produced. Hard drives with a rotation speed of 7200 rpm are preferable, but they are more expensive and noisier than drives with 5400 rpm.
Cache size or cache memory. Hard drive cache is a special type RAM(buffer memory) that stores frequently used data. Due to the fact that the data is taken from a high-speed electronic cache, and not from a relatively slow mechanical medium, then HDD performance grows up. The larger the cache size, the fewer disk accesses. The size of buffer memory is measured in megabytes and in modern hard drives is 16-128 MB.
All of the above characteristics are indicated in the price lists of computers in the store, and now you can easily navigate your choice.
Share.When the computer starts, a set of firmware stored in BIOS chip, checks equipment. If everything is fine, it transfers control to the operating system boot loader. Then the OS loads and you start using the computer. At the same time, where was it stored before turning on the computer? operating system? How did your essay, which you wrote all night, remain intact after the PC was turned off? Again, where is it stored?
Okay, I probably went too far and you all know very well that computer data is stored on the hard drive. However, not everyone knows what it is and how it works, and since you are here, we conclude that we would like to find out. Well, let's find out!
What is a hard drive
As per tradition, let's take a look definition of hard disk on Wikipedia:
Hard drive (screw, hard drive, storage device hard magnetic disks, HDD, HDD, HMDD) is a random access storage device based on the principle of magnetic recording.
Used in the vast majority of computers, and also as separately connected storage devices backup copies data, as file storage, etc.
Let's figure it out a little. I like the term " hard disk drive ". These five words convey the essence. HDD is a device whose purpose long time store the data recorded on it. The basis of HDDs are hard (aluminum) disks with a special coating, onto which information is recorded using special heads.
I will not consider the recording process itself in detail - essentially this is the physics of the last grades of school, and I’m sure you have no desire to delve into this, and that’s not what the article is about at all.
Let us also pay attention to the phrase: “ random access "Which, roughly speaking, means that we (the computer) can read information from any section of the railway at any time.
An important fact is that the HDD memory is not volatile, that is, no matter whether the power is connected or not, the information recorded on the device will not disappear anywhere. This important difference permanent memory computer, from temporary ().
Looking at a computer hard drive in real life, you will not see either disks or heads, since all this is hidden in a sealed case (hermetic zone). Externally, the hard drive looks like this:
Why does a computer need a hard drive?
Let's look at what a HDD is in a computer, that is, what role it plays in a PC. It is clear that it stores data, but how and what. Here we highlight the following functions of the HDD:
- Storage of OS, user software and their settings;
- Storage of user files: music, videos, images, documents, etc.;
- Using part of the hard disk space to store data that does not fit in RAM (swap file) or storing the contents of RAM while using sleep mode;
As you can see, the computer hard drive is not just a dump of photos, music and videos. The entire operating system is stored on it, and in addition, the hard drive helps cope with the load on the RAM, taking on some of its functions.
What does a hard drive consist of?
We partially mentioned the components of a hard drive, now we will look at this in more detail. So, the main components of the HDD:
- Frame — protects hard drive mechanisms from dust and moisture. As a rule, it is sealed so that moisture and dust do not get inside;
- Discs (pancakes) - plates made of a certain metal alloy, coated on both sides, on which data is recorded. The number of plates can be different - from one (in budget options) to several;
- Engine — on the spindle of which the pancakes are fixed;
- Head block - a design of interconnected levers (rocker arms) and heads. The part of the hard drive that reads and writes information to it. For one pancake, a pair of heads is used, since both the upper and lower parts are working;
- Positioning device (actuator ) - a mechanism that drives the head block. Consists of a pair of permanent neodymium magnets and a coil located at the end of the head block;
- Controller - electronic chip work manager HDD;
- Parking zone - a place inside the hard drive next to the disks or on their inner part, where the heads are lowered (parked) during downtime, so as not to damage the working surface of the pancakes.
This is a simple hard drive device. It was formed many years ago, and no fundamental changes have been made to it for a long time. And we move on.
How does a hard drive work?
After power is supplied to the HDD, the motor, on the spindle of which the pancakes are attached, begins to spin up. Having reached the speed at which a constant flow of air is formed at the surface of the disks, the heads begin to move.
This sequence (first the disks spin up, and then the heads start working) is necessary so that, due to the resulting air flow, the heads float above the plates. Yes, they never touch the surface of the disks, otherwise the latter would be instantly damaged. However, the distance from the surface of the magnetic plates to the heads is so small (~10 nm) that you cannot see it with the naked eye.
After startup, first of all, service information about state of rigid disk and other necessary information about it, located on the so-called zero track. Only then does work with the data begin.
Information on a computer's hard drive is recorded on tracks, which, in turn, are divided into sectors (like a pizza cut into pieces). To write files, several sectors are combined into a cluster, which is the smallest place where a file can be written.
In addition to this “horizontal” disk partition, there is also a conventional “vertical” partition. Since all the heads are combined, they are always positioned above the same track number, each above its own disk. Thus, during HDD operation the heads seem to draw a cylinder:
While the HDD is running, it essentially performs two commands: read and write. When it is necessary to execute a write command, the area on the disk where it will be performed is calculated, then the heads are positioned and, in fact, the command is executed. The result is then checked. In addition to writing data directly to the disk, the information also ends up in its cache.
If the controller receives a read command, it first checks whether the required information is in the cache. If it is not there, the coordinates for positioning the heads are calculated again, then the heads are positioned and the data is read.
After completion of work, when the power to the hard drive disappears, automatic parking heads in the parking area.
This is basically how a computer hard drive works. In reality, everything is much more complicated, but to the average user, most likely, such details are not needed, so let's finish this section and move on.
Types of hard drives and their manufacturers
Today, there are actually three main manufacturers on the market hard drives: Western Digital (WD), Toshiba, Seagate. They fully cover the demand for devices of all types and requirements. The remaining companies either went bankrupt, were absorbed by one of the main three, or were repurposed.
If we talk about the types of HDD, they can be divided as follows:
- For laptops, the main parameter is the device size of 2.5 inches. This allows them to be compactly placed in the laptop case;
- For a PC - in this case it is also possible to use 2.5" hard drives, but as a rule, 3.5" are used;
- External hard drives are devices that are separately connected to a PC/laptop, most often serving as file storage.
There is also a special type of hard drive - for servers. They are identical to regular PC ones, but may differ in connection interfaces and greater performance.
All other divisions of HDD into types come from their characteristics, so let’s consider them.
Hard drive specifications
So, the main characteristics of a computer hard drive:
- Volume — an indicator of the maximum possible amount of data that can be stored on the disk. The first thing they usually look at when choosing HDD. This figure can reach 10 TB, although for a home PC they often choose 500 GB - 1 TB;
- Form factor — size of the hard disk. The most common are 3.5 and 2.5 inches. As mentioned above, 2.5″ in most cases are installed in laptops. They are also used in external HDDs. 3.5″ is installed in PCs and servers. The form factor also affects the volume, since larger disk can fit more data;
- Spindle speed — at what speed do the pancakes rotate? The most common are 4200, 5400, 7200 and 10000 rpm. This characteristic directly affects the performance, as well as the price of the device. The higher the speed, the greater both values;
- Interface - method (connector type) HDD connections to the computer. The most popular interface for internal hard drives today is SATA (older computers used IDE). External hard drives are usually connected via USB or FireWire. In addition to those listed, there are also such interfaces as SCSI, SAS;
- Buffer volume (cache memory) - type fast memory(by type of RAM) hard drive installed on the controller, designed for temporary storage of data that is most often accessed. The buffer size can be 16, 32 or 64 MB;
- Random access time — the time during which the HDD is guaranteed to write or read from any part of the disk. Ranges from 3 to 15 ms;
In addition to the above characteristics, you can also find such indicators as:
The hard drive, or hard drive, is the main and very important part of the computer. It stores not only the operating system that runs the computer, but also all the information of a client or several clients. It often happens that the value of information is many times greater than not only the cost of the hard drive itself, but also the cost of the computer as a whole. Therefore, the security of information largely depends on the quality and reliability of such a storage device. A modern hard drive looks like the one shown in the picture.
What is a hard drive?
So, what exactly is a storage device, the performance of which determines the well-being and good mood of its owner? In fact, a hard drive is a high-tech equipment that stores digital information even when the computer is turned off.
To be more precise, a hard drive consists of several magnetic disks onto which information is applied and read using a magnetic head. These heads, together with magnetic disks, are in a vacuum, which allows the drive to operate without the influence of the external environment on the process of writing and reading information.
What types of hard drives are there?
So, we found out that a hard drive is an information storage device for a computer. Now let's figure out what types of HDD there are. First of all, it should be noted that hard drives can be divided into two categories:
- External drives that can be connected to any computer via a USB interface. In some ways they resemble a flash drive, only large sizes. Special software such hard drives do not need it.
- Internal HDD drives are installed inside computers and have specific connectors for both power and information transfer.
Internal HDDs are also divided into several categories. There are several criteria by which a hard drive can be classified. This is the physical size of the hard drive. There are three standard sizes:
- 5.5 inches. Typically, hard drives of this size are used in desktop computers, Where free space quite a lot.
- 3.5 inches are used mainly in laptops where space is limited and large amounts of memory are needed.
- 2.5 inches are used in ultrabooks where space is very limited.
Another feature by which drives are classified is the data exchange protocol between the hard drive and the computer. What protocols can the hard drive use? They are as follows:
- IDE- old version protocol, which was used mainly on computers and laptops before 2000.
- SCSI is a contemporary of IDE, more high speed version drive management, which was used mainly in server machines. It required special drivers to use such hard drives.
- SATA- modern version protocol, which has several options and has high speed recording and reading information. Used in almost all modern computer systems.
Hard drive problems
One of the most frightening messages that can be seen on the screen says that the computer does not see the hard drive. Why is this so scary for computer users? With such a malfunction, the device does not load the operating system, and accordingly, practically no actions provided for by this system can be performed.
What could cause this problem? The simplest problem leading to this result is a violation of the integrity of the power cables or system interface. Often, dust or dirt getting inside such a connector leads to this malfunction. And most experienced users are not particularly scared when such a message appears, but simply reconnect the power and interface connectors. This inscription may look something like the one shown in the photo above.
Hard drive not visible for BIOS
When such a malfunction occurs, the first thing to determine is whether this problem physical or software. How to find out? After a message appears that the computer does not see the hard drive, you need to reboot the machine and enter the BIOS. What is BIOS? This is a program that is written into the ROM of the computer's motherboard. It loads even before the operating system and determines the peripheral devices with which it will work motherboard. For BIOS boot you need to press the appropriate key on the keyboard, usually the DEL or F2 button. After entering the BIOS, you can see the following picture.
This photo shows that the BIOS was not detected on computer hard disks. In this case, the problem described above could occur, and the computer, being disconnected from the power cable or interface, is invisible to the BIOS. On the other hand, any malfunction in the hard drive control board will lead to such a problem. Moreover, if it is possible to solve this problem, then only in the appropriate service center. It is almost impossible to eliminate it on your own at home.
Windows 7 does not see the hard drive
But there are times when the hard drive is visible to the BIOS, but the operating system does not boot or constant reboot Windows. In what cases does this happen? Then, when, while working with the operating system, one of the system files or an error occurred during rewriting and the file is not read correctly. Physical damage to the hard drive, scratching or chipping of the disk surface may also occur. If one of the system files was located in this location, then the operating system will not be able to read it and will issue, as system administrators say, blue screen death, which prompts you to reboot the system. If the error repeats, it is better to contact system administrator. Sometimes such software errors can be easily fixed without reinstalling the operating system. But it happens that they are fatal, and they can only be corrected with the help of complete reinstallation systems. To solve this kind of problem they usually use system utilities who are engaged in restoration software errors. What are these programs?
Hard drive software errors
There are quite a lot of programs for recovering software errors, which can be divided into two categories. The first includes utilities that are located inside the system and can be used after full load operating system. These are sets of programs for servicing hard drives.
For example, how to maintain a Windows 7 hard drive? You can maintain your drive directly from the program. To do this, just go to “My Computer” and select the disk that we want to service. Click on the "Properties" tab and see the following picture, shown in the photo above.
Hard drive maintenance programs
As you can see in the picture, the user is offered three utilities:
- Check for errors.
- Disk archiving.
Only the first program corrects errors, and the others will simply service this disk. But there are programs that work without an operating system. The advantage of such utilities is that they can maintain the disk even when the operating system does not boot. For example, one of these programs is called FDISK and was developed by Microsoft as a disk maintenance utility before installing the operating system. It is used advanced users computer equipment Norton Disk Doctor, and there are actually quite a lot of such programs, so the choice largely depends on preferences specific person. Before installing Windows from a hard drive, it is advisable to service it with a similar program and correct possible errors.
Hard drive recovery
Often, many users are faced with the problem of recovering data from a problematic hard drive. As mentioned above, often the information stored on it is valued much more than the hard drive itself. Therefore, the work of recovering lost data is not only valuable, but also highly paid. Much depends on how the information disappeared. It is important to remember how Windows deletes information from your hard drive.
The operating system does not erase information that the user wants to remove. It simply deletes the hard drive's table of contents, which allows you to find this information. This table of contents is called a FAT table. And if after that the body is hard Windows disk 10 other information was not recorded, it is quite easy to restore it. There are many programs that can do this job. According to many users, one of the best is Acronis Recovery Expert.
Hard Drive Backup
Be that as it may, no user wants to be constantly under the threat that valuable information is in danger. Therefore, efforts are made to minimize risks. What can be done? Backup useful information the hard drive as a whole or hard sector disk helps solve this problem.
What backup methods are there?
- IN manual mode. The user independently chooses what information and when the program will save. Some companies in own offices prefer to produce backup data at the end work shift. But there is a danger of losing information that has accumulated during the day.
- Backup to automatic mode. At the same time, the program includes how often and what should be copied and saved.
- Creating a mirrored RAID array that stores all the information from the main hard drive in parallel on another hard drive. If the latter fails, you can easily use a mirror.
Selecting a hard drive
Paying great attention to the safety of information, you should not forget about the choice of the hard drive manufacturer, as well as technical parameters, characterizing the quality of this hard drive. If we talk about the brand of the drive manufacturer, then it is worth choosing a more well-known company, although such a hard drive will cost a little more. Some users prefer Seagate.
If we talk about technical parameters, then, all things being equal, it is worth paying attention to the speed of reading and writing information. Sometimes this data will help you make a choice in favor of one or another hard drive.
Let's sum it up
So, a hard drive is a very valuable and important information on the computer. Therefore, you need to put a lot of effort into choosing a high-quality hard drive. You should also take care to regularly maintain your device. In addition, it is important to pay attention to the security of information, if any, on your computer. If you make all these efforts, your hard drive will serve you for a long time, and the information on it will be completely safe. The operation of your device is entirely in your hands, so take all measures to ensure its normal functioning.
One of the main components of any computer is a hard magnetic disk, which is used as a storage device for permanent information.
This device has several “informal” names: hard disk, hard drive or “screw”.
Why is a hard drive called a hard drive?
Computer hard drives began to be called Winchesters in the United States in the 70s of the twentieth century. Then IBM released the first analogue of modern hard drives: a device consisting of two cabinets, inside of which there were magnetic disks with a capacity of 30 MB each.
It was marked with the inscription “30x30” - exactly the same inscription was present on the rifle of the famous company “Winchester”. At first, hard drives were called “hard drives” as a joke, but soon the name firmly stuck to them and became almost official.
How does a computer's hard drive work?
Principle hard devices computer disk remains unchanged for several decades. Of course, the technical details have undergone major changes, but the main features of the design remain the same as forty years ago.
The hard drive consists of several thin glass or aluminum disks, on the surface of which a thin layer of chromium dioxide is applied. The disks are fixed strictly parallel to each other on the spindle and covered with an aluminum housing. In addition, there is a block of magnetic heads inside the case.
The electric motor drives the discs and they begin to rotate at a constant speed. The resulting air flows keep the heads at a certain distance from the surface of the disks, so that there are no scratches or abrasions on it.
The top layer of the hard drive is used to write and read information. This work is performed by magnetic heads that move over the surface of the disks, finding the desired positions using special marks on the disk.
Of course, the diameters of modern hard drives have decreased significantly compared to the first models, and information capacity, on the contrary, has increased hundreds of thousands of times. However, the first hard drives had approximately the same basic design.
Writing information to the hard drive
The process of writing and reading information is based on a binary code: the presence or absence of a signal. The information block encrypted in this way, converted into vibrations electric current, is supplied to the block of magnetic heads of the hard drive.
The heads find the desired section of the disk and convert current fluctuations into oscillations magnetic field. In this case, microscopic areas are created on the surface of the disk: some are magnetized, others are not magnetized. Binary code The recordings are thus transferred to the hard drive.
The process of reading information looks similar: a block of magnetic heads passes over the desired area of the disk, and due to the presence of oscillations in the magnetic field generated by the surface of the disk, the electrical voltage in the heads either increases or decreases.
The read information goes to where it is processed and displayed on the screen. The monitor shows us text or an image that is stored on the hard drive.
Formatting your hard drive
The process of formatting a hard drive is similar to erasing information from a school board. Magnetic heads completely destroy everything that was previously written on the disk and break its surface into sectors for new recordings. Brand new disks are also formatted: this is necessary to streamline the writing and reading process.
Presentation of information on the hard drive
Information is written to the hard drive not randomly, but in the form of circles (tracks) located one inside the other. The hard drive consists of several disks, and each head is responsible for one side of one disk, but they all move simultaneously to the same depth.
Therefore, information is recorded on several disks at once, the tracks of which form a cylindrical surface. Disks are divided into sectors, with one sector track containing 512 bytes.
The logical representation of information is different from its physical arrangement. During formatting, the hard drive is divided into so-called logical drives, each of which is designated Latin letter. Size of each logical drive assigned arbitrarily, at the request of the computer owner.
This presentation of information has been chosen for the convenience of users. To convert logical coordinates into physical ones, there is a special translator located in the hard drive case.
Good day to everyone, my dear friends and readers. A friend told me that when he was still working in a video salon, a granny of about 70-80 years old came to see him. She approached a friend and said that she needed “HADEDE”. The friend didn’t seem to understand right away and asked again, “hadede?” She repeated it again, but when she saw that her friend was not smoking, she took out a piece of paper and said that her grandson told her to buy HADEDE.
On that piece of paper it was written HDD 160 GB. Well, the friend grinned and said that it was a hard drive for a computer and directed them to another store. But that’s not what’s surprising anymore. How could a grandson even send his grandmother to get a hard drive? Well, did he fall out of the oak tree?
But what am I getting at? Let me tell you what a HDD is in a computer. Then you definitely won’t have any questions if you want to buy it for yourself.
HDD (Hard Disk Drive) is the hard drive of your computer. You can hear in conversations and alternative names of this device, for example “Winchester”, “Screw”, “Hard”, “Hard”, etc. This device is needed to store your information; in addition, the operating system in which you work is installed on it. Those. Without a hard drive, you can't do much with your computer.
The hard drive is a long-term source of memory and after the power is turned off, all information remains on it, unlike fast RAM. Therefore, you can always store your files, photos, music, etc. on it. But of course this is a device, so don’t forget about it for greater security.
I can already hear the question “Why is it called a hard drive? These are small arms!” Indeed, what could a storage device have in common with a gun? The fact is that in 1973, the well-known company IBM released the hard drive model 3340, but for the sake of harmony they began to call it simply “30-30”, which meant two modules of 30 megabytes each.
Chief Kenneth Haughton found the 30-30 consonance in the famous rifle. The fact is that the cartridges for this rifle had the same marking 30-30, where the first number meant the size of the caliber in inches (0.30 - 7.62 cm), and the second number meant the weight of gunpowder in grains (this is not a typo, but a measure of weight ), which the cartridge was filled with (30 grains is approximately 1.94 grams).
For convenience, it was decided to use this name as slang. True, this slang has not been used by Americans for a long time, but in our country it has not yet gone out of use, although more often it can be heard in the abbreviated name “Screw”.
Hard drive device
Externally, this thing looks like a small rectangular box, but inside it there are several magnetic disks on one spindle, which look somewhat similar to a CD. And of course, there is a certain reading head, which runs along these magnetic plates, reading all the information. Well, of course, there are other components, but I think that these are all details.
And this work is somewhat similar to the work of a record player, only the reader does not have a needle and does not touch magnetic disks, although the distance between them is simply insignificant.
Basic characteristics of the hard drive
Volume
The capacity of your hard drive determines how much information you can store on it. Over time, memory sizes have increased by new hard increase because there is a real need for it. If on my first computer the volume was 40 GB and that was enough for me, now I have 2000 GB on my computer and I have already used half of it. Of course, some can be removed without tears).
But there is one trick. Manufacturers write the size, for example, 500 GB, but when you connect the hard drive to the computer, you will see a much smaller volume there, about 476 GB. Where did the 24 extra GB go? Yes, it's very simple.
Manufacturers round up the sizes, saying 1 GB is 1000 MB, 1 MB is 1000 KB, etc. It turns out that they are selling you a disk with a capacity of 500 million bytes, and if you divide it by 1000, and then by another 1000, you get 500 GB.
But 1 GB is actually not 1000, but 1024 MB, just as 1 MB is not 1000, but 1024 KB. As a result, it turns out that we divide 500 million by 1024, and then by 1024 again and get our 476 GB with kopecks. My 2 terabyte disk consumes about 140 GB. Not bad, right? In general, now you will know.
Rotation speed
The performance of a hard drive is also determined by the spindle speed. And the higher this speed, the greater the disk performance, but the more energy required and the greater the likelihood of failure.
For laptops and external hard drives, the speed of 5400 rpm is most often used, since this is really more expedient for these devices. The speed of information exchange is lower, but there is a lower probability of failure.
On desktop computers, in most cases, hard drives with a speed of 7200 rpm are installed. This is really beneficial here, since stationary equipment usually has more powerful equipment that can operate at such a speed. Plus, the computer is constantly connected to the outlet, which means there will be no shortage of energy.
There are also more rpm, even 15,000, but I won’t consider them here.
Connection interface
And of course, hard drives are constantly being improved and even their connection connectors are changing. Let's see what connectors there are.
IDE (ATA/PATA) - the so-called parallel interface with possible data usage speeds of up to 133 MB per second. But today this interface is outdated and hard drives with such a connector are no longer produced.
SATA - Serial interface, a more modern one, which replaced the IDE. The standard has at the moment there are three different revisions with at different speeds data transfer: SATA 1 - up to 150 MB/s, SATA 2 - up to 300 MB/s, SATA 3, up to 600 MB/s.
USB - This standard applies to external portable hard drives, which connect to the computer via USB and you can work quietly. The advantage of such a device is that you can turn it off at any time without turning off the computer itself.
There are other interfaces, such as SCSI or SAS, but these are no longer mandatory standards for simple use.
Form factor
I was recently asked, what is the form factor of hard drives? Everything is simple here. These are just its dimensions. There are 2.5 and 3.5 inches. Of course, there are others, but no one uses them in everyday life or they are long outdated.
Laptops are equipped with a 2.5" HDD, and desktop computers 3.5". I think that you will not confuse anything)
![](https://i2.wp.com/koskomp.ru/wp-content/uploads/2016/05/vosstanovlenie_dannyh_s_neispravnogo_zhestkogo_diska.jpg)
Well, that seems to be all I wanted to tell you in this article. But I can already hear: “Why didn’t you tell me about the SSD?” My friends, we need to write a separate article about SSDs, especially since this type is fast solid state drive. In general, I will definitely write about him).
Best regards, Dmitry Kostin.