What are hard drives for? How does a hard drive work?

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Every computer has a hard drive or, as it is often called, a hard drive, which is the main storage location for all information used by the computer and its user. The installed software is stored on the hard drive. operating system, all programs used by the user, and data. The processor takes the information necessary for processing from the hard drive and then writes it back to the media. The amount of information stored on a hard drive depends on its size.

The very first models of hard drives allowed storing up to 10 MB of data on their disks, which was a lot in those days. Nowadays, modern storage devices allow you to store thousands and tens of thousands of megabytes. Memory capacity per modern models measured in gigabytes and terabytes. This makes it possible to store great amount movies, music, videos, games and other data. A significant increase in the amount of memory on HDD is associated with progressive development computer technology, causing movies, games, and other data to take up more and more free space.

Design features of hard drives

A modern hard drive consists of several metal disks on which information is recorded. The discs are coated with iron oxide or another special compound that can store the impact magnetic field. The number of disks depends on the volume of the media and is usually in the range from 1 to 3. Metal disks are ideally even, smooth and balanced, due to which they can rotate with high speed, according to the standard it can be 5400, 7200 or 10000 rpm.

Special heads move along the disks with the highest positioning accuracy. Each disk has 2 magnetic heads. Reading data from the surface of disks is carried out by installing special magnetoresistive heads; they work depending on how the magnetic field on the surface of the disk changes. Data is transferred to the computer as a result of receiving analog signal, going digital.

On disks, information is located in tracks located around a circle. To work with data stored on media, magnetic heads move along tracks. The heads are moved using a special solenoid drive. Such heads can access any location on the disk due to their high rotation speed. The heads are located on both sides of the disks, so each of them carries out work on one side and is fully responsible for it.

A sector on a hard drive allows you to store 512 bytes of information, and each track hard drive consists of many sectors. The maximum amount of information that can be stored on a hard drive depends on the number of sectors, heads and cylinders. In count HDDs may be the same, but their memory volumes will be completely different. This is due to the fact that to increase capacity, it is more convenient to increase the density of sectors on each of the disks than to increase their number, which will lead to a significant increase in the size of the media. The development of computer technology leads to the fact that each PC component becomes smaller external dimensions, and the opportunities, on the contrary, increase.

There are such concepts as physical and logical disk placement. Physical is how the storage medium is structured inside, and logical is how the computer sees it. In reality, the physical and the logical are completely different. If physically, for example, 3 disks can be installed inside a hard drive, then logically there can be any number of them and any size, one logical drive can be the size of two or more physical ones and vice versa.

During the production of hard drives, it is almost impossible to avoid damage to sectors or tracks, but they are not used and are not taken into account by the media due to markings.

There are hard drives designed for use in home PCs, and others for use in servers. The latter are subject to much greater requirements, because they work with a significant load and must provide high productivity and speed.

Characteristics of hard drives

In order to choose the right hard drive suitable for a specific purpose, you need to understand large quantities characteristics. The first thing you should pay attention to is the form factor. On desktop PCs, 3.5-inch hard drives are installed, and on laptops, 2.5-inch ones. There are also other less common form factors. The second important parameter is the interface through which the device is connected to the computer. PCs use various variations of the SATA interface.

One of the important parameters is capacity, which determines the amount of data stored on the device. The rotation speed of the shaft on which the disks are located affects the speed of working with information.

At choosing a hard disk, you should pay attention to the buffer size, which directly affects the speed of the device’s processing of information.

Each hard drive makes noise during operation, just like any other mechanical device. During operation, noise can cause significant inconvenience, so you need to pay attention to its level when choosing a model suitable for your PC.

If you plan to frequently move the device from one computer to another, then such a parameter as shock resistance is important. The higher it is, the less likely it is to lose information during an impact or damage the hard drive.

While working with information, the disk provides the requested information at a certain speed. This indicator is called “Random Access Time” and the lower it is, the faster the request will be transmitted.

Having an understanding of all the parameters, characteristics and design of modern hard drives, you can quickly select the appropriate hard drive to perform your tasks on your PC.

Greetings, dear readers, guests and simply interested visitors! Today I want to answer a question that is difficult for many users - why do you need a hard drive? The fact is that if the purpose of many devices is clear even from the name, then in the case of hard drive This question comes up often.

What it is? What are its functions? What does it look like and where to find it in system unit? How to choose it? Saw interest Ask higher? Sit back, now you will get answers to everything!

Hard drive - why not soft?

HDD(other names - hard drive, hard drive) is a compact device in the system unit that is connected to small cables (wires). Its purpose is to store absolutely all user information. This includes basic programs such as the operating system, settings files, and other computer controls. In addition, the hard drive stores everything that the user downloads onto it.

Games, music, movies, photographs, books - all this is located on millions of clusters inside the device itself.
A hard drive is so called because inside its powerful and durable case there are hidden metal plates on which, in fact, all information is recorded.

And many years earlier, data was stored on thin plastic sheets coated with magnetic coating. They, quite logically, easily bent and broke.

Now these are not used anywhere due to their fragility, unreliability and absolute irrelevance. Regular hard drives they were completely forced out not only from system units, but even from people’s consciousness. Nowadays few people remember floppy disks for storing data, they are excellently replaced by CDs and DVDs, flash drives.

Types of hard drives

All currently existing hard drives differ from each other in many parameters; below I will present to your attention the most important of them. If you take a closer look at them and understand what you need, it’s easy to decide which one to choose and how:

Connection interface

There are several options - IDE and SATA. While the connector for the latter can still be found on older modifications of motherboards, IDE is almost never found anywhere. Replaced both of them new interface, called SATA 2. The plug through which the hard drive is connected to the board is literally 1 cm long and 2-3 mm wide (the wire itself is dark pink or red). For comparison: the IDE connector is a giant cable 4-5 cm long. It can easily be accidentally bent and, as a result, broken.

There are also SSD hard drives. There are no disks in them, there are no moving elements at all. They work on the principle of regular flash drives, but with much more memory. It should be borne in mind that such disks work much faster than classic hard drives. But with equal amounts of memory, their price is several times higher than that of HDDs.
And if you wish, you can purchase and use external hard disk. There are no problems at all - just select the required amount of memory and connect via USB.

Storage capacity

Previously, all the information on a computer could fit on one small floppy disk, but the digital age has destroyed this standard. Now the minimum volume that can be found is 80 GB. This space is enough for about 5-6 modern games or 30-40 movies. good quality. There is no talk about music and files like MS Word and Excel, since they can be recorded in thousands.
If you plan to handle a large amount of information, then the best option you will have a hard drive with 500 GB or more.

Data transfer rate

An important indicator. Extremely important for those who want fast work without brakes. The higher this speed, the faster the hard drive will exchange information with the system so that it displays it on the monitor.

Energy consumption

You need to pay attention to this indicator if you are taking a device for a laptop, as this will save battery power.
There are other characteristics, but few people are interested in them. These include impact resistance, noise level and others.

Connecting a drive

After choosing, many users begin to think about how to properly connect the hard drive. In fact, this is a very simple process. Simply insert it into the designated slot (the bottom part is located directly behind the front panel) and screw it tightly. Next, you need to insert the wire included in the kit into the corresponding connector on the motherboard and directly into the hard drive itself. That's it, the connection process is complete.

Another question is connecting the fan (cooler). It is mounted directly on the hard drive, and is connected to another port on the motherboard. On each model, this connector is located in different places, so you need to look for the specific point in the user manual.

I think I have given a comprehensive answer to the question about the need for tough disk and criteria for selecting it for a laptop. If you think that the material was useful, share it with your friends on social networks. Who knows, maybe this will make the choice easier for them too!

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The hard drive, or hard drive, is the main and very important part computer. It stores not only the operating system that controls 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 drive. A modern hard drive looks like the one shown in the picture.

What is a hard drive?

So, what exactly is a storage device, on the performance of which the well-being and good mood his 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 HDD types 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 larger in size. 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 there is a lot of free space.
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 a high speed of writing 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 such a malfunction? The simplest problem leading to this result is a violation of the integrity of the power cables or the 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 boots before the operating system and determines the peripheral devices that the motherboard will work with. 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 there is a 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. It can also happen physical damage hard drive, scratch or chip of the disk surface. 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 by experienced 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 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 prefer to produce in their own offices 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 you should choose 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.

Summarize

So, a hard drive is a very valuable and important information in 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, then 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.

This article will only talk about hard drives(HDD) that is, about magnetic disk media. The next article will be about SSDs.

What is a hard drive

By tradition, let's look at the definition of a hard drive on Wikipedia:
A hard drive (screw, hard drive, hard disk drive, 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’s 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 (RAM).
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.
I think you understand what HDD is. Go ahead.

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 content random access memory while using sleep mode;
- As you can see, a computer’s 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:
- Case - protects the hard drive mechanisms from dust and moisture. As a rule, it is sealed so that moisture and dust do not get inside;
- Disks (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), up to several;
- Engine - on the spindle of which the pancakes are fixed;
- Head block - a structure 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 actuates 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 area - a place inside the hard drive next to the disks or on their inner part, where the heads are lowered (parked) during idle time, so as not to damage the working surface of the pancakes.
This is so simple hard device disk. 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 others necessary information about him, 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, the heads are automatically parked in the parking zone.
Like this in general outline and the computer hard drive is working. 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 disks and their manufacturers

Today, there are actually three main hard drive manufacturers on the market: 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:

1. For laptops, the main parameter is the device size of 2.5 inches. This allows them to be compactly placed in the laptop case;
2. For a PC - in this case it is also possible to use 2.5″ hard drives, but as a rule, 3.5″ are used;
3. External hard disks 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.

Characteristics of hard disks

So, the main ones characteristics of hard computer disk:

Volume is an indicator of the maximum possible amount of data that can be stored on a disk. The first thing they usually look at when choosing a HDD. This figure can reach 10 TB, although for a home PC they often choose 500 GB - 1 TB;
- Form factor - the 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 rotation speed - at what speed 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 capacity (cache memory) - type fast memory(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:

Data transfer rate;
- Number of I/O operations per second;
- Noise level;
- Reliability;
- Impact resistance, etc.;
On account HDD characteristics this is all.

HDD(HDD, SCREW, WINCHESTER) is an information storage device in personal computer. Hard drive – designed for storing and transmitting information. A hard drive stores data on the magnetic surface of the disk. Information is recorded and retrieved using magnetic heads. A hard drive can contain several platters called disks. The motor that rotates the disk turns on when power is applied to the disk and remains turned on until the power is removed. The motor rotates at a constant speed, measured in revolutions per minute (rpm). Data is organized on a disk in cylinders, tracks, and sectors. Cylinders are concentric tracks on disks, located one above the other. The track is then divided into sectors. The disk has a magnetic layer on each side. Each pair of heads is mounted, as it were, on a “fork” that clasps each disk. This “fork” moves above the surface of the disk using a separate servo motor (and not a stepper, as is often mistakenly thought - a stepper motor does not allow you to move quickly above the surface). All hard drives have spare sectors that are used by its management circuitry if bad sectors are detected on the drive.

Hard drive device:

Hard drive interfaces

A storage interface is a set of electronics that ensures the exchange of information between the device controller (cache buffer) and the computer. An interface is the way the hard drive and computer motherboard interact. It is a set of special lines and a special protocol (a set of data transfer rules). That is, purely physically, it is a cable (cable, wire), on both sides of which there are inputs, and on the hard drive and motherboard there are special ports (places where the cable is connected). Thus, the concept of interface includes a connecting cable and ports located on the devices it connects.

IDE- translated from English “Integrated Drive Electronics”, which literally means “built-in controller”. It was only later that IDE began to be called an interface for data transfer, since the controller (located in the device, usually in hard drives and optical drives) and the motherboard needed to be connected with something. It (IDE) is also called ATA (Advanced Technology Attachment), it turns out something like “Advanced Connection Technology”.

What can I say, although the IDE was very slow ( throughput data transmission channel ranged from 100 to 133 megabytes per second per different versions IDE - and even then purely theoretically, in practice much less), but it allowed you to simultaneously connect two devices to the motherboard at once, using one cable.

Moreover, in the case of connecting two devices at once, the line capacity was divided in half. However, this is far from the only drawback of the IDE. The wire itself, as can be seen from the figure, is quite wide and, when connected, will take up the lion's share free space in the system unit, which will negatively affect the cooling of the entire system as a whole. All in all IDE is already outdated morally and physically, for this reason the IDE connector can no longer be found on many modern motherboards, although until recently they were still installed (in quantities of 1 piece) on budget boards and on some boards in the mid-price segment.

The next interface, no less popular than the IDE in its time, is SATA (Serial ATA), characteristic feature which is serial data transmission. It is worth noting that at the time of writing this article, it is the most widespread for use in PCs.

Interfaces SATA, SATA 2(II), SATA 3 (III)

In 2002, the first hard drives appeared, with a progressive interface at that time SATA . Maximum speed the data transfer rate of which was 150 MB/s.

If we talk about the advantages, the first thing that catches your eye is the replacement 80-wire loop (Fig. 1), to a seven-core SATA cable (Fig. 3), which is much more resistant to interference, which made it possible to increase the standard cable length from 46 cm to 1 m. Also, appropriate SATA connectors(Fig. 4), which are several times more compact than the connectors of the previous IDE standard. This made it possible to place more connectors on the motherboard; now more than 6 can be found on new motherboards SATA connectors, versus traditional 2-3 IDEs in older motherboards oriented to this standard.

Then, the SATA II standard appeared, the data transfer speed reached 300 MB/s. This standard has acquired many advantages, among them: Native Command Queuing technology (it is this technology that made it possible to achieve a speed of 300 MB/s), hot-plugging disks, executing several commands in one transaction, and others.

Well, in 2009 the interface was introduced SATA 3 . This standard provides for data transfer at speeds 600 MB/s (For hard drives"Oh" how redundant).

Interface improvements can include more efficient power management and, of course, increased speed.

It should be noted that SATA, SATA II and SATA III are completely compatible.

1956 - IBM 350 hard drive included in the first serial computer IBM 305 RAMAC. The drive occupied a box the size of a large refrigerator and weighed 971 kg, and the total memory capacity of 50 thin disks covered with pure iron with a diameter of 610 mm rotating in it was about 5 million 6-bit bytes.
1980 - the first 5.25-inch Winchester, Shugart ST-506, 5 MB.
1981 - 5.25-inch Shugart ST-412, 10 MB.
1986 - SCSI, ATA standards.
1990 - maximum capacity 320 MB.
1995 - maximum capacity 2 GB.
1997 - maximum capacity 10 GB.
1998 - UDMA/33 and ATAPI standards.
1999 - IBM releases Microdrive with capacities of 170 and 340 MB.
2000 - IBM releases Microdrive with capacities of 500 MB and 1 GB.
2002 - ATA/ATAPI-6 standard and drives with a capacity of over 137 GB.
2003 - the appearance of SATA.
2003 - Hitachi releases Microdrive with a capacity of 2 GB.
2004 - Seagate releases ST1 - an analogue of Microdrive with a capacity of 2.5 and 5 GB.
2005 - maximum capacity 500 GB.
2005 - Serial ATA 3G standard.
2005 - SAS appeared.
2005 - Seagate releases ST1 - an analogue of Microdrive with a capacity of 8 GB.
2006 - application of the perpendicular recording method in commercial drives.
2006 - the appearance of the first “hybrid” hard drives containing a flash memory unit.
2006 - Seagate releases ST1 - an analogue of the Microdrive with a capacity of 12 GB.
2007 - Hitachi introduces the first commercial drive with a capacity of 1 TB.
2009 - based on 500 GB platters from Western Digital, then Seagate Technology LLC released models with a capacity of 2 TB.
2009 - Samsung released the first hard drives with USB interface 2.0
2009 - Western Digital announced the creation of 2.5-inch HDDs with a capacity of 1 TB
2009 - the emergence of the SATA 3.0 standard.
2010 - Seagate releases a 3 TB hard drive.
2010 - Samsung releases a hard drive with platters with a recording density of 667 GB on one platter
2011 - Western Digital released the first disk on 750 GB platters.