What is HDD, hard disk and hard drive. What is hdd in a computer The meaning of a hard disk in a computer

We, users of a personal computer, often come across the abbreviation HDD. And the desire to find out what an HDD is, where it is and what it is for is justified.

HDD stands for "hard disk drive". Simply put, it's a hard drive. Gradually fading into the past, they are being replaced by SSDs, but they will occupy their niche in the HDD market for a long time to come.

Why is the drive "hard"

HDD in the computer as soon as they are not called. Hard drive, hard drive, hard drive, screw - just a small list of his names. Why all the same "hard disk drive"?

Unlike "floppy" disks (floppies), HDD data is written to hard platters, which, in turn, are covered with a layer of ferromagnetic material. They are called nothing more than "magnetic disks". A hard drive uses one or more platters on the same axis. Readers (heads) do not touch the surface of the plates during operation. This is explained simply: with the rapid rotation of the plates, a layer of oncoming air flow is formed. The distance between the reader and the work surface is very small - only a few nanometers, and the air layer, which excludes mechanical contact, ensures a long service life. If the plates do not rotate at the proper speed, then the heads are in the so-called "parking" zone - outside the boundaries of the plates.

A distinctive feature of the HDD in a computer is that the storage medium is combined with the drive, as well as with the necessary electronics unit in one housing.

HDD Main Features

Like any technical device, a hard drive has a number of characteristics, based on which, we can draw conclusions about its relevance.

• Capacity is one of the most significant quantities. Specifies the amount of data that the drive can store.
• Dimensions (form factor). The most common variations are 3.5 and 2.5 inches. Specifies the width of the device.
• The speed of rotation of the axis, spindle. The number of revolutions per minute. The parameter significantly affects the speed of access to data and directly on the speed of their transfer. The most common options: 4200, 5400, 7200, 10,000 rpm.
• The number of I/O operations per second. For modern disks, this number approaches 50 (with random access to data), with sequential access, respectively, higher - about 100.
• Power consumption is an important parameter for portable devices (we are talking about laptops / netbooks).
• Buffer size. Buffer - intermediate memory. Its purpose is to smooth out read/write speed differences. In modern HDDs, it is usually located in the range from 8 to 64 megabytes.

I hope we were able to figure out what an HDD is in a computer, and even expand our horizons a little in the world of computer hardware.

A hard drive, hard drive or just a screw, hard disk, hdd (Hard Disk Drive) - this storage device has several names, it is the main storage device for storing information in all modern computers, laptops and servers. It is on this device that all your photos, videos, music, movies are recorded, and the operating system of the computer itself is recorded on it. Now SSD drives and hybrid SSHD drives are becoming more common, we will talk about them and their pros and cons in a separate article.

What are the disks?

In the store today you can find hard drives of different parameters, how do they differ? Let's try to understand the main differences with you and highlight several characteristics of drives.

Form factor (size)

The parameter shows the width of the hard drive in inches. The main widths of 3.5 inches and 2.5 inches are used in modern computers and laptops, as well as in external portable and stationary drives and network storages.

For a stationary home computer, the standard size is 3.5 inches, in modern cases there are 2.5-inch drive bays, they are mainly designed to install an SSD drive, put in a computer instead of a 3.5-inch drive, 2.5-inch drives don’t make much sense , only in very compact cases, such as micro-ATX.

In laptops, on the contrary, space saving is very relevant and 2.5-inch form-facts are used for them. There are smaller drives - 1.8 inches, 1.3 inches, 0.8 inches, but in modern devices you will not find them anymore.

Capacity (Why is the capacity of the drive smaller than advertised?)

A parameter that directly affects how much information we can record and store on our computer or laptop. Manufacturers indicate the capacity at the rate of 1 kilobyte = 1000 bytes, and computers calculate differently 1 KB = 1024 bytes, hence the confusion arises for users who encounter this for the first time and the larger the volume, the greater the difference in the final volume. Now the volume of disks is measured in terabytes, which is more than enough to store a collection of not only photos, but also music with films.

Interface

You will find drives with a SATA connector in all modern devices today. The only difference is the data transfer rate.

ATA aka PATA (IDE)

Drives with this interface are no longer manufactured or installed in modern devices, but you can find them in older computers. Initially, the interface was called ATA, but after the appearance of a more modern and faster SATA in 2003, it was renamed PATA.

The name IDE was coined by WD (Western Digital) in 1986 for marketing reasons when it developed the first version of this connectivity standard.

SCSI and SAS

SAS drives are used in server hardware. Replaced the SCSI interface. The average user should know only that they are designed for completely different tasks and are not used in home PCs.

Spindle speed

The number of revolutions of the spindle (the axis on which the plate or several plates rotate inside the disk). There are several standards, in home computers and laptops drives with a rotation speed of 5400, 7200 and 10000 rpm are used, on server equipment there are rotation speeds of 15000 rpm. The parameter affects the time of access to information.

There are a few more parameters such as noise level, MTBF, etc. in modern drives, these parameters correspond to standard criteria and do not differ significantly, we will pay attention to them when we compare and select hard drives.

External drives (portable or desktop)

These are disks already familiar to us, enclosed in an external plastic or metal box, in which a control board or even a whole mini-PC is installed on the board. At the output of such drives there are various outputs, the main connectors are mini-USB, micro-USB, micro-USB 3.0, fireware and others, portable models are powered by a USB connector. Stationary have a separate power cable. Modern models of external drives can work over a wireless wi-fi network. Now on sale you can find network storages with several disks in one case, which can be connected into RAID arrays. Separately, we will talk about all these devices in future articles.

Hard drives, or, as they are also called, hard drives, are one of the most important components of a computer system. Everyone knows about it. But far from every modern user even in principle guesses how a hard drive functions. The principle of operation, in general, is quite simple for a basic understanding, but there are some nuances here, 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, will immediately answer that the hard drive (aka hard drive, aka Hard Drive or HDD) will immediately answer that it is used to store information.

In general, it is true. Do not forget that on the hard disk, 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 some marks by which you can quickly find the necessary information on the disk.

Modern models are quite diverse: conventional HDDs, external hard drives, high-speed SSD solid-state drives, although it is not customary to attribute them to hard drives. Further, it is proposed to consider the device and the principle of operation of the 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 the following can be distinguished:

• 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 thinking about why they call hard drives related to small arms. It would seem that what can 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 popular at that time gun "30-30 Winchester". True, in the early 90s in America and Europe this name practically fell into disuse, but it still remains popular in the post-Soviet space.

The device and principle of operation of the hard drive

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

The hard drive itself is a set of platters, the number of which can vary from four to nine, interconnected by a shaft (axis) called a spindle. The plates are placed one above the other. Most often, the material for their manufacture is 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 are responsible for writing and reading information (one for each plate), 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.

At the same time, the basic principle of the computer hard drive is that information is not recorded anywhere, but in strictly defined locations, called sectors, which are located on concentric tracks or tracks. To avoid confusion, uniform rules apply. This means that the principles of operation of hard disk drives, from the point of view of their logical structure, are universal. So, for example, the size of one sector, adopted as a single 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 principle of operation of a hard disk in this regard are that the exchange of information is carried out by whole clusters (an integer number of chains of sectors).

But how is information read? The principles of operation of a hard disk drive are as follows: using a special bracket, the reading head moves 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 (platters). All tracks with the same serial numbers are called cylinders.

In this case, one more principle of hard disk operation can be distinguished: the closer the read 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 physics of magnetism, formulated by Faraday and Maxwell.

As already mentioned, plates made of non-magnetically sensitive material are coated with a magnetic coating, the thickness of which is only a few micrometers. In the process of work, a magnetic field arises, which has the so-called domain structure.

The 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 an external magnetic field is applied, the disk's own field begins to orient itself strictly along the magnetic lines, and when the impact 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 during recording, and when reading, the residual magnetization zone, being opposite the head, creates an electromotive force or EMF. Further, everything is simple: a change in the EMF corresponds to a unit in a 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 for computer science reasons, can be associated as a certain dotted sequence of bits of information. But, since the location of such points cannot be absolutely accurately calculated, it is necessary to set some pre-provided marks on the disk that helped determine the desired location. The creation of such marks is called formatting (roughly speaking, breaking the disk into tracks and sectors combined into clusters).

The logical structure and principle of operation of the hard disk 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 need to talk about bringing the hard drive into working condition. How to initialize a new hard drive will be discussed separately.

Low-level formatting involves a 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 disk 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 plate. Thus, when organizing direct access, the same RAM accesses directly to a given address, and does not search for the necessary information over the entire surface, due to which speed 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 applicable to the creation of logical partitions, which are a certain area of ​​​​the main hard disk that works according to the same principles.

Logical formatting primarily affects the system area, which consists of the boot sector and partition tables (boot record 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, when errors and failures occur, is not subject to change or deletion.

HDD Main Features

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

The principle of operation of the hard drive and the 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);
• speed (data access speed, reading and writing information);
• interface (connection method, controller type).

Capacity is the total amount of information that can be written and stored on a hard drive. The HDD industry is developing so fast that today hard drives with volumes of the order of 2 TB and above have already come into use. And, as it is believed, this is not the limit.

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

Drives with an IDE interface are not expensive, but the main drawbacks include a limited number of simultaneously connected devices (maximum four) and a low data transfer rate (even if Ultra DMA direct memory access or Ultra ATA protocols (Mode 2 and Mode 2 and Mode 2) are supported. 4).Although, as it is believed, their use allows you to increase the read / write speed to the level of 16 Mb / s, but 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 in included with the motherboard.

Speaking about what is the principle of operation of a hard drive and characteristics, one cannot ignore and which is the successor to the IDE ATA version. The advantage of this technology is that the read/write speed can be increased up to 100 Mb/s by using the high-speed Fireware IEEE-1394 bus.

Finally, the SCSI interface is the most flexible and fastest compared to the previous two (write/read speed reaches 160 Mb/s and more). But these hard drives are almost twice as expensive. But the number of simultaneously connected storage devices is from seven to fifteen, the connection can be made without de-energizing 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 rate and I/O throughput, is usually expressed in terms of transfer time and amount of sequential data transferred, and is expressed in Mbps.

Some additional options

Speaking about what is the principle of operation of a hard drive and what parameters affect its operation, one cannot ignore some additional characteristics that may affect the performance or even the life of the device.

Here in the first place is the rotation speed, which directly affects the search and initialization (recognition) time of the desired sector. This is the so-called hidden seek time - the interval during which the desired sector turns to the read head. Today, several standards have been adopted for spindle speed expressed in revolutions per minute with dwell times 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 on searching for sectors, and in physical terms - on disk rotation until the required platter positioning point is set for the head.

Another parameter is the internal transfer rate. On the outer tracks, it is minimal, but increases with a gradual transition to the inner 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 faster read speed. The external speed has fixed values ​​and directly depends on the interface used.

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

Main requirements for HDD

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

The main standard for most HDDs is considered to be 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-test function is responsible for this, which monitors the status of individual elements of the hard drive, carrying out continuous monitoring. On the basis of the collected data, even a certain forecast of the appearance of possible malfunctions in the future can be formed.

It goes without saying that the user should not be left out. So, for example, when working with a HDD, it is extremely important to observe the optimal temperature regime (0 - 50 ± 10 degrees Celsius), avoid shocks, bumps 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 reading head and the magnetic surface of the hard drive, and a human hair - 5-10 times.

Initialization issues in the system when replacing a hard drive

Now a few words about what actions should 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 dwell 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, in the disk administration section, initialize and create a boot entry, create a simple volume, assign an identifier (letter) to it and format it with a choice of file system. Only after that the new "screw" will be completely ready for work.

Conclusion

That, in fact, is all that briefly concerns the basics of the functioning and characteristics of modern hard drives. The principle of operation of an external hard drive was not considered fundamentally here, since it is practically no different from what is used for stationary HDDs. The only difference is only in the method of connecting an additional drive to a computer or laptop. The most common is the connection 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.

For the rest, it seems that many have at least a little understood how a hard drive of any type functions. Perhaps, too many topics were given above, 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 production and application of HDDs.

Hard disk or HDD This is a device that allows you to store information for a long time and which is non-volatile. In simple words, an iron box where all your documents, movies, operating system and everything else are located. If we draw a life analogy, then this is something like a big album. Taking a pencil in hand, you can draw or write essays. If you don't like something, you can always take the "eraser". The bottom line is that while the album is on the shelf, all the data remains intact.

There are two important aspects in this case. The first is long-term storage. The second is energy independence. If in the first case everything should be clear from the album example, then for the second case I will give some explanations. The bottom line is that the hard drive does not require power to store information, unlike RAM. So you can turn off your computer from the network and know that the data will be safe.

Note: There is a common version of where the slang names of this box came from. Today, a hard drive is often referred to as a hard drive or, for short, a screw. It came from the fact that the first such device had a code similar to Winchester rifle cartridges. It is hard to say how true this is, but the version is considered the most real.

Let's take a closer look at this box.

If you notice, then I have already mentioned the abbreviation HDD several times and for a reason. The fact is that the technical name of this box is a hard disk drive or hard (magnetic) disk drive.

But, back to the hard drive device. This box is based on the technology of magnetic recording of information. And here's how it works. There are round hard drives (they are also often called pancakes) covered with a ferromagnetic material (it can change its magnetic properties). There is a special moving head (consists of two parts), which, in fact, reads and writes data (part of the head for reading, part for writing).

The process itself is as follows. The disk is constantly spinning at a fairly high speed, and the head walks along the disk and either reads data or writes at the right time. It is important to note that the head does not touch the disk, otherwise the disk coating could be damaged. When the disk is turned off, the head is in a special zone (parking), again to protect the ferromagnetic coating from damage.

It is worth knowing that the internal mechanism is designed in such a way that, purely physically, it would be very difficult to damage the surface of the data disc. However, over time, parts of the ferromagnetic surface may become unusable. Here, as in the well-known expression - "Nothing lasts forever."

It is also worth knowing that there may be several such plates inside the hard drive box. As you may have guessed, the number of pancakes affects the amount of information stored. But, it is not limited to this. For example, a long time ago, disks were 1.5 times larger than today's, and 20-40MB were placed on them.

Figure 1 Simplified Diagram of a Round Hard Drive

Note: In the figure, the numbers indicate: 1 - geometric sector, 2 - track sector, 3 - track, 4 - cluster.

Consider, in a little more detail, the very surface of the pancakes. So that the storage and recording of information can be structured, the entire surface is divided into special tracks. Then the entire disk is divided into geometric sectors (equal to each other). The part of the track that is inside this geometric object is called the track sector or simply sectors. The combination of several sectors is called a cluster.

Since the disks spin at a fairly high speed (for example, 7200 rpm), it is the cluster that is used as the minimum storage unit. Typically, a cluster is represented by a size of 4 KB and consists of 8 sectors of 512 bytes. By the way, this is why the real size of a text file consisting of only one character will be 4 KB, since, in principle, the size is divided precisely into clusters.

Note: It is worth knowing that there are methods that allow you to store data of several files in one cluster, but usually the division goes exactly by clusters.

Note: I also advise you to read the article Solid state hard drive or SSD drive, as this is the next round of data storage devices.

Hard drive specifications

If with a hard drive device, I hope it became clear to you, then for the sake of completeness, it remains to consider the issue of the main characteristics of the HDD.

1. Form Factor. The words are terrible, but in fact they mean only the physical size of the disk. For desktop computers, it is usually 3.5 inches, for laptops it is less, only 2.5 inches.

2. Capacity. This is essentially the size of how much data a hard drive can store. Today, disks are measured in gigabytes and terabytes.

3. Spindle speed. This is exactly the same speed with which pancakes are spinning. Usually it is 5400 for laptops and 7200 for regular computers. There are other speeds, but they are simply not needed for home use.

4. Noise level. Here, probably, you can guess what is at stake. There are very loud hard drives, usually the simplest ones, and there are also quieter ones.

5. Shock resistance or in the common people survivability. In fact, it indicates what kind of overloads the hard drive can endure without damaging data. However, I strongly advise you not to check this characteristic.

6. Access interface. The interface defines the connectors that are used to connect drives to the computer. Previously, almost all HDDs for home computers were IDE, but today we are mainly talking about SATA. In the case of external drives, usually USB. It is worth knowing that in reality the connector of the disk itself is not USB, just an adapter with a controller is used inside the box.

Good day to all, my dear friends and readers. One friend told me that when he was still working in a video salon, a granny of 70-80 years old came to him. She approached a friend and said that she needed "HADEDE". A friend, as it were, did not immediately understand and asked again, they say hadede? She repeated it again, but when she saw that her friend was not drinking, she took out a piece of paper and said that her grandson had told her to buy Khadede.

On that piece of paper it was written HDD 160 GB. Well a friend chuckled and said it was a computer hard drive and sent them to another store. But that is no longer surprising. How could a granddaughter even send his grandmother for a hard drive? Well, did it collapse from the oak tree?

But what am I getting at? Let me tell you all the same what an HDD is in a computer. Then you will definitely not have 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 for 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 really do much with your computer.

The hard disk is a long-term source of memory and after a power outage, 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 do not forget about for greater security.

Theory of the origin of the name "Winchester"

I already hear the question “Why is it called a hard drive? It's a firearm!" Indeed, what can a storage device and a gun have in common? The fact is that in 1973 the notorious IBM company released the hard drive model 3340, but for consonance it was simply called “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 digit meant the size of the caliber in inches (0.30 - 7.62 cm), and the second digit meant the weight of the gunpowder in grains (this is not a typo, but a measure of weight ), which was loaded with a cartridge (30 grains is approximately 1.94 grams).

For convenience, it was decided to use such a name as slang. True, this slang has not been used by Americans for a long time, but we have not yet gone out of use, although more often it can be heard in the abbreviated name "Screw".

Hard disk device

Outwardly, this thing looks like a small rectangular box, but inside it there are several magnetic disks on one spindle, which look something like 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 is without a needle and does not touch magnetic disks, although the distance between them is simply negligible.

Main characteristics of the hard drive

Volume

The size of your hard drive determines how much information you can store on it. Over time, the memory sizes on new hard drives increase, as there is a real need for this. If on my first computer the volume was 40 GB and it was enough for me, now I have 2000 GB on my computer and I have already scored half. Of course, part 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 a computer, you will see a much smaller volume there, somewhere around 476 GB. And where did the extra 24 GB go? Yes, everything is very simple.

Manufacturers round up the sizes of values, they say 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 by 1000, and then another 1000, you get 500 GB.

But after all, in 1 GB, in fact, not 1000, but 1024 MB, just as in 1 MB, not 1000, but 1024 KB. As a result, it turns out that we divide 500 million by 1024, and then by 1024 and get our 476 GB with a penny. I have about 140 GB on a 2 terabyte disk. Not bad, right? In general, now you will know.

Rotational speed

The performance of a hard drive is also determined by the spindle speed. And the greater this speed, the greater the performance of the disk, but the more energy is required and the greater the likelihood of failure.

For laptops and external hard drives, 5400 rpm is most often used, since this is really more appropriate for these devices. The speed of information exchange is less, but the probability of failure is less.

On stationary computers, in most cases, hard drives are installed at a speed of 7200 rpm. Here it is really beneficial, since the stationary ones, as a rule, have more powerful equipment capable of operating at such a speed. Plus, the computer is constantly connected to the outlet, which means there will be no shortage of energy.

There are more revolutions, even 15000, but I will not 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 are.

IDE (ATA/PATA) is the so-called parallel interface with a possible data usage rate of up to 133 MB per second. But today this interface is outdated and rigid with such a connector is no longer produced.

SATA - Serial interface, already more modern, which has come to replace IDE. The standard currently has three different revisions with different data transfer rates: SATA 1 - up to 150 MB / s, SATA 2 - up to 300 MB / s, SATA 3, up to 600 MB / s.

USB - This standard refers to external portable hard drives that connect to a computer via USB and you can work safely. 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 here, 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 outdated for a long time.

2.5" HDD is inserted into laptops, and 3.5" into stationary computers. I don't think you're confusing anything)

Well, that seems to be all that I wanted to tell you in this article. But I already hear: “Why didn’t you tell me about the SSD?”. My friends, you need to write a separate article about SSD, especially since this type is a high-speed solid-state drive. In general, I will definitely write about him).

Sincerely, Dmitry Kostin.