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 the HDD. 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 HDD, external hard drives, high-speed solid-state drives SSD, although it is not customary to attribute them to hard drives. Next, it is proposed to consider the device and the principle of operation 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 consonant 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 features 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.

At the same time, 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 (on Windows systems, this quick format or Quick format). In addition, these processes are applicable to the creation of logical partitions, which are some area of ​​the main hard drive 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 defines how the device connects to motherboard, which controller is used, how reading and writing is done, etc. The main and most common interfaces are IDE, SATA and SCSI.

Drives with an IDE interface are not expensive, but the main disadvantages include a limited number of simultaneously connected devices (maximum four) and a low data transfer rate (even if DMA is supported). Ultra DMA or Ultra ATA protocols (Mode 2 and Mode 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 with 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. Based on 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, the hard drive must be connected and looked in BIOS settings, whether new hardware has been determined, in the disk administration section, initialize and create boot record, create a simple volume, give it an identifier (letter) 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.

The hard disk drive is almost one of the most important elements of a modern computer. Since it is designed primarily for long-term storage of your data, it can be games, movies and other large files stored on your PC. And it would be a pity if it could suddenly break, as a result of which you can lose all your data, which can be very difficult to recover. And in order to properly operate and replace this element, you need to understand how it works and what it is - a hard drive.

In this article, you will learn about the operation of the hard drive, its components and specifications Oh.

Typically, the main elements of a hard drive are several round aluminum plates. Unlike floppy disks (forgotten floppy disks), they are difficult to bend, which is why the name hard disk appeared. In some devices, they are installed non-removable, and are called fixed (fixeddisk). But in ordinary desktop computers and even some models of laptops and tablets, they can be easily replaced.

Figure: Hard drive without top cover

The note!

Why are hard drives sometimes called a hard drive and what do they have to do with firearms. Sometime in the 1960s, IBM released a high-speed hard drive at that time with a development number of 30-30. Which coincided with the designation of the famous Winchester rifled weapon, and therefore this term was soon fixed in computer jargon. But in fact, hard drives have nothing to do with real hard drives.

How a hard drive works

Recording and reading of information located on the concentric circles of the hard disk, divided into sectors, is carried out by means of universal write/read heads.

All sides of the disk provide their own track for writing and reading, but the heads are located on a common drive for all disks. For this reason, the heads move synchronously.

YouTube Video: Open Hard Drive Operation

The normal operation of the drive does not allow contact between the heads and the magnetic surface of the disk. However, in the event of a power outage and the device stops, the heads still sink to the magnetic surface.

During hard disk operation, a small air gap forms between the surface of the rotating platter and the head. If a speck of dust enters this gap or the device is shaken, there is a high chance that the head will collide with a rotating surface. A strong impact can cause head failure. The result of this output may be damage to several bytes, or the device may be completely inoperable. For this reason, in many devices, the magnetic surface is alloyed, after which a special lubricant is applied to it, which makes it possible to cope with periodic shaking of the heads.

Some modern disks use a load/unload mechanism that prevents the heads from touching the magnetic surface even if the power is turned off.

High and low level formatting

Using high-level formatting allows the operating system to create structures that make it easier to work with files and data stored on the hard drive. All available partitions (logical drives) are provided with a volume boot sector, two copies of the file allocation table, and a root directory. Through the above structures, the operating system manages to allocate disk space, track the location of files, and bypass damaged areas on the disk.

In other words, high-level formatting comes down to creating a table of contents for the disk and the file system (FAT, NTFS, etc.). Only low-level formatting, during which the disk is divided into tracks and sectors, can be attributed to "real" formatting. With the FORMAT DOS command, a floppy disk is subjected to both types of formatting at once, while a hard disk is only high-level formatted.

In order to perform low-level formatting on a hard disk, you need to use a special program, most often provided by the disk manufacturer. Formatting floppy disks with FORMAT involves performing both operations, while in the case of hard disks, the above operations must be performed separately. Moreover, the hard disk is subjected to the third operation - the creation of partitions, which are a prerequisite for using more than one operating system on one PC.

The organization of several partitions provides the ability to install on each of them its own operating infrastructure with a separate volume and logical drives. Each volume or logical drive has its own letter designation (for example disk C,D or E).

What is a hard drive made of?

Almost every modern hard drive includes the same set of components:

discs(their number most often reaches 5 pieces);

read/write heads(their number most often reaches 10 pieces);

actuator mechanism(this mechanism sets the heads to the required position);

disc drive motor(a device that rotates disks);

air filter(filters located inside the drive case);

printed circuit board with control schemes(through this component, the drive and the controller are controlled);

cables and connectors(electronic HDD components).

A sealed box - HDA - is most often used as a housing for disks, heads, a head drive mechanism and a disk drive motor. Usually this box is a single unit, which is almost never opened. Other non-HDA components, such as the configuration items, circuit board, and bezel, are removable.

Automatic head parking and control system

In the event of a power outage, a contact parking system is provided, the task of which is to lower the bar with heads onto the discs themselves. Regardless of the fact that the drive withstands tens of thousands of ascents and descents of reading heads, all this must take place in areas specially designated for these actions.

During constant ascents and descents, inevitable abrasion of the magnetic layer occurs. If the drive is subjected to shock after wear, then most likely damage to the disk or heads will occur. To prevent the above troubles, modern drives are equipped with a special loading / unloading mechanism, which is a plate that is placed on the outer surface hard drives. This measure prevents the head and the magnetic surface from touching even if the power is turned off. When the voltage is turned off, the drive independently "parks" the heads on the surface of the inclined plate.

A little about air filters and air

Almost all hard drives are equipped with two air filters: a barometric filter and a recirculation filter. What distinguishes the above filters from the replaceable models used in older generation drives is that they are placed inside the case and their replacement is not provided until the end of the service life.

Older drives used the technology of constantly moving air in and out of the case, using a filter that needed to be changed periodically.

The developers of modern drives had to abandon this scheme, and therefore the recirculation filter, which is located in the sealed HDA case, is used only to filter the air inside the box from the smallest particles trapped inside the case. Regardless of all precautions taken, small particles are still formed after repeated “landing” and “takeoffs” of the heads. Taking into account the fact that the case of the drive is distinguished by its tightness and air is pumped in it, it continues to function even in highly polluted environments.

Interface connectors and connections

Many modern hard drives are equipped with several interface connectors designed to connect to a power source and to the system as a whole. As a rule, the drive contains at least three types of connectors:

interface connectors;

connector for power supply;

ground connector.

Interface connectors deserve special attention, since they are designed to receive/transmit commands and data by the drive. Many standards do not exclude the possibility of connecting multiple drives to the same bus.

As mentioned above, HDD drives can be equipped with several interface connectors:

MFM and ESDI- extinct connectors used on the first hard drives;

IDE/ATA- a connector for connecting drives, which for a long time was the most common due to its low cost. Technically, this interface is similar to the 16-bit ISA bus. The subsequent development of IDE standards contributed to an increase in the speed of data exchange, as well as the emergence of the ability to directly access memory using DMA technology;

Serial ATA- a connector that replaced the IDE, which is physically a unidirectional line used for serial data transfer. Being in compatibility mode is similar to the IDE interface, however, the presence of a "native" mode allows you to take advantage of an additional set of features.

SCSI- a universal interface that was actively used on servers to connect HDDs and other devices. Despite good technical performance, it did not become as common as IDE due to its high cost.

SAS- serial analogue of SCSI.

USB- an interface that is needed to connect external hard drives. The exchange of information in this case occurs through the USB Mass Storage protocol.

firewire- a connector similar to USB, is required to connect an external HDD.

fiber channel- an interface used by high-end systems due to the high data transfer rate.

Hard drive quality metrics

Capacity- the amount of information held by the drive. This figure in modern hard drives can reach up to 4 terabytes (4000 gigabytes);

Performance. This parameter has a direct impact on the response time and the average information transfer rate;

Reliability- an indicator determined by the mean time between failures.

Physical capacity limits

The maximum amount of capacity used by a hard drive depends on a number of factors, including the interface, drivers, operating system, and file system.

The first ATA drive, released in 1986, had a capacity limit of 137 GB.

Different BIOS versions also contributed to a decrease in the maximum capacity of hard drives, and therefore systems built before 1998 had a capacity of up to 8.4 GB, and systems released before 1994 - 528 MB.

Even after solving problems with the BIOS, the capacity limit of drives with an ATA connection interface remained, its maximum value was 137 GB. This limitation was overcome by the ATA-6 standard released in 2001. This standard used an extended addressing scheme, which, in turn, contributed to an increase in storage capacity up to 144 GB. Such a decision made it possible to bring to light drives with PATA and SATA interfaces, in which the amount of information they can hold is higher than the specified limit of 137 GB.

OS limits on maximum volume

Almost all modern operating systems do not impose any restrictions on such an indicator as the capacity of hard drives, which cannot be said about earlier versions of operating systems.

So, for example, DOS did not recognize hard drives with a capacity exceeding 8.4 GB, since access to the drives in this case was performed through LBA addressing, while in DOS 6.x and earlier versions only CHS addressing was supported.

There is also a hard disk capacity limit if Windows 95 is installed. The maximum value for this limit is 32 GB. In addition, updated Windows versions 95 is only supported file system FAT16, which in turn imposes a 2 GB size limit on partition sizes. From this it follows that in the case of using a 30 GB hard disk, it must be divided into 15 partitions.

Operating Room Limitations Windows systems 98 allow the use of larger hard drives.

Characteristics and parameters

Each hard disk has a list of technical characteristics, according to which its hierarchy of use is established.

The first thing to pay attention to is the type of interface being used. Recently, every computer has begun to use as an improved and faster interface SATA.

Second no less important point— the amount of free space on the hard drive. Its minimum value today is only 80 GB, while the maximum is 4 TB.

Another important characteristic in the case of purchasing a laptop is the form factor of the hard drive.

In this case, models with a size of 2.5 inches are considered the most popular, while in desktop PCs the size is 3.5 inches.

Do not neglect the spindle speed, the minimum values ​​​​are 4200, the maximum ones are 15000 rpm. All of the above characteristics have a direct impact on the speed of the hard drive, which is expressed in Mb / s.

Hard drive speed

Of no small importance are the speed indicators of the hard drive, which are determined by:

Spindle speed, which is measured in revolutions per minute. Its task is not to directly identify the real exchange rate, it only allows you to distinguish a faster device from a slower device.

Access time. This parameter calculates the time spent by the hard drive from receiving a command to transmitting information over the interface. Most often I figure the average and maximum values.

Head positioning time. This value specifies the time it takes for the heads to move and set from one track to another track.

Bandwidth or disk performance during serial transfer of large amounts of data.

Internal baud rate or the rate of information transmitted from the controller to the heads.

External baud rate or the rate of information transmitted over the external interface.

A little about S.M.A.R.T.

S.M.A.R.T.- a utility designed to independently check the status of modern hard drives that support PATA and SATA interfaces, and also work in personal computers with Windows operating system (from NT to Vista).

S.M.A.R.T. counts and analyzes the status of connected hard drives at regular intervals, regardless of whether the operating system or not. After the analysis has been carried out, the diagnostic result icon is displayed in the right corner of the taskbar. Based on the results obtained during the S.M.A.R.T. diagnostics, the icon may indicate:

On the excellent condition of each hard drive connected to the computer that supports S.M.A.R.T. technology;

The fact that one or more status indicators do not meet the threshold value, while the Pre-Failure / Advisory parameters have a value of zero. The above hard state disk is not considered pre-crash, however, if this hard drive contains important information, it is recommended to save it on another medium as often as possible or replace the HDD.

The fact that one or more status indicators do not meet the threshold value, while the Pre-Failure / Advisory parameters have an active value. According to the developers of hard drives, this is a pre-emergency state, and it is not worth storing information on such a hard drive.

Reliability factor

Such an indicator as the reliability of data storage is one of the most important features hard drive. The failure factor of a hard drive is once every hundred years, from which we can conclude that the HDD is considered the most reliable source of data storage. At the same time, the reliability of each disk is directly affected by the operating conditions and the device itself. Sometimes manufacturers supply the market with a completely “raw” product, and therefore it is impossible to neglect backup and completely rely on the hard drive.

Cost and price

Every day the cost of HDD becomes less and less. So, for example, today the price of a 500 GB ATA hard disk is on average $120, in comparison, in 1983 a 10 MB hard drive cost $1,800.

From the above statement, we can conclude that the cost of the HDD will continue to fall, and therefore in the future everyone will be able to purchase fairly capacious drives at affordable prices.

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

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

Ordinary hard disk drives (HDD) are large in size, not high in speed, and are not expensive. Solid State Drives (SSDs) are the fastest, but they are smaller and much more expensive. An intermediate option between them are hybrid drives (SSHD), which have sufficient capacity, are faster than conventional HDDs and cost a little more.

Hard drives are considered the most reliable western digital(WD). The best SSD drives are produced by: Samsung, Intel, Crucial, SanDisk, Plextor. As more budget options, you can consider: A-DATA, Corsair, GoodRAM, WD, HyperX, since there are the least problems with them. And hybrid drives (SSHD) are produced mainly by Seagate.

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

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

For gaming computer it is advisable to take an SSD with a capacity of 240-256 GB, it will be possible to install several games on it.
A-Data Ultimate SU650 240GB Hard Drive

For a more economical option for a multimedia or gaming PC, you can purchase one 1TB Seagate Hybrid Drive (SSHD), which is not as fast as an SSD, but still somewhat faster than a regular HDD.
Seagate FireCuda ST1000DX002 1TB Hard Drive

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

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

2. Disk types

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

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

Solid state drives (SSDs) are relatively small (120-960 GB) but very fast (450-550 MB/s). They are much more expensive and are used to install the operating system and some programs to increase the speed of the computer.

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

3. Application of HDD, SSD and SSHD drives

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

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

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

4. Physical dimensions of disks

Hard drives for desktop computers are 3.5 inches in size.

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

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

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

5. Hard Drive Connectors

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

5.1. interface connector

An interface connector is called a connector for connecting a disk to a motherboard using a special cable (loop).

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

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

5.2. Power connector

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

6. Volumes of hard drives

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

6.1. Hard Disk Drive (HDD) Capacity for Computer

For a computer designed for typing and accessing the Internet, the smallest of modern hard drives is enough - 320-500 GB.

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

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

Please note that the computer motherboard must support UEFI, otherwise the operating system will not see the entire disk capacity of more than 2 TB.

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

6.2. Hard disk (HDD) capacity for a laptop

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

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

It is important to consider what thickness of disks your laptop supports. Discs with a thickness of 7 mm will fit into any model, and 9 mm thick may not fit everywhere, although there are not many of these already produced.

6.3. Solid state drive (SSD) capacity

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

Modern operating systems (Windows 7,8,10) require about 40 GB of space for their work and grow with updates. In addition, at least the main programs must be installed on the SSD, otherwise there will not be much sense from it. Well, for normal operation, the SSD should always have 15-30% free space.

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

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

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

6.4. Data backup

When choosing a disk size, it is also desirable to take into account the need to create backup user files (video, photo, etc.) that will be stored on it. Otherwise, you risk losing everything that you have accumulated over the years in one moment. Therefore, it is often more expedient to purchase not one huge disk, but two smaller disks - one for work, the other (possibly external) for backing up files.

7. Basic parameters of disks

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

7.1. Spindle speed

The spindle has hard and hybrid disks based on magnetic platters (HDD, SSHD). Since SSDs are based on memory chips, they do not have a spindle. The speed of the hard drive spindle depends on the speed of its operation.

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

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

7.2. Memory Buffer Size

A buffer is a hard drive cache based on memory chips. This buffer is designed to speed up the hard drive, but has a small impact (on the order of 5-10%).

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

8. Speed ​​characteristics of disks

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

8.1. Linear Reading Speed

Linear reading speed is the main parameter for any disk and dramatically affects the speed of its operation.

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

Solid State Drives (SSDs) are much faster and their read speed, depending on the model, is 160-560 MB/s. Optimal in terms of price / speed ratio are SSD drives with a read speed of 450-500 Mb / s.

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

8.2. Linear write speed

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

SSDs can have write speeds that are less than or equal to read speeds. In the price lists, these parameters are indicated through a slash (for example, 510/430), where a larger number means the read speed, a smaller one means the write speed.

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

8.3. Access time

Access time is the second most important disk parameter after read/write speed. The access time affects the speed of reading/copying small files especially strongly. The lower this setting, the better. In addition, low access time indirectly indicates a higher quality of the hard disk (HDD).

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

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

Hybrid disk drives (SSHD) achieve lower access times than HDDs, which are comparable to SSDs, with additional built-in flash memory. But due to the limited amount of flash memory, a lower access time is only achieved when accessing the most frequently used files that have ended up in this flash memory. Usually this system files, which provides faster computer boot speed and high system responsiveness, but does not drastically affect the operation of large programs and games, since they simply do not fit in the limited amount of fast SSHD memory.

9. Manufacturers of hard drives (HDD, SSHD)

The most popular hard drive manufacturers are as follows:

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

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

• WD Blue- low cost general purpose discs
• WD Green– quiet and economical (often switched off)
• WD Black– fast and reliable
• WD Red– for data storage systems (NAS)
• WD Purple– for video surveillance systems
• WD Gold- for servers
• WD Re– for RAID arrays
• WDSe– for scalable corporate systems

Blue is the most regular discs suitable for low-cost office and multimedia PCs. Black ones combine high speed and reliability, I recommend using them in powerful systems. The rest are designed for specific tasks.

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

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

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

10. Manufacturers of Solid State Drives (SSDs)

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

• Samsung
• Intel
• Crucial
• SanDisk
• Plextor

More budget options include:

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

11. SSD memory type

SSD drives can be built on different types of memory:

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

12. Speed ​​of hard drives (HDD, SSHD)

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

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

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

Here's what a picture with a disk test from the search looks like.

As you can see, this picture shows the average linear read speed and random access time, which we are interested in. Check only that the model number in the picture matches the model number of your drive.

In addition, according to the schedule, you can roughly determine the quality of the disc. An uneven schedule with large jumps and high access time indirectly indicate inaccurate low-quality disk mechanics.

A beautiful cyclical or simply uniform graph without big jumps, combined with a low access time, speaks of the exact high-quality mechanics of the disk.

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

13. Optimal drive

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

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

14. The cost of HDD and SSD drives

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

The price of HDDs mostly depends on the capacity of the disk and slightly on the manufacturer (by 5-10%). Therefore, it is not advisable to save on the quality of HDDs. Get models from recommended manufacturers, albeit a little more expensive, as they will last longer.

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

15. Links

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

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 failure, all information remains on it, in contrast to a fast random access memory. 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. There are, of course, others, but they Everyday life no one uses or they are outdated.

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 high-speed solid state drive. In general, I will definitely write about him).

Sincerely, Dmitry Kostin.

Hello! Finally, I found the time to please you with new material! Sorry for not writing for so long. The fact is that I was working on one project, which I will tell you about in the future (subscribe to blog updates).

Why buy a new hard drive? Everyone may have their own reasons, but basically this means that the speed of work and loading of programs has noticeably decreased, or there is not enough space to write new information to the computer. Whatever the reason for buying a new hard drive, there is something for everyone to think about before making a purchase. So let's figure it out how to choose a hard drive for a computer and what you need to consider before buying. And below we will analyze a real example of buying a hard drive. After all, a sudden and thoughtless decision can lead to the fact that the new HDD will not satisfy your needs.

How to choose a hard drive for your computer

Hard drives are internal, which are installed in the computer, and external. Internal ones are common (3.5” for computers) and for laptops (2.5” form factor). This article will focus specifically on internal drives.

Hard disk capacity

Disks with 40 or 80 GB of memory are gone. Now on the market, the volume of a hard drive is measured in hundreds of gigabytes and terabytes. What disk size should I choose? A lot depends on what kind of work is being done on the computer and how much space you really need. For more, you have to pay more. It's best to base your needs on a 20-50% margin rather than how much disk space your friend or neighbor has installed, as they may actually need a lot of space.

Considering that hard drives with a capacity of less than 500GB can no longer be found in stores, we will assume that this is the minimum sufficient volume. So much space is enough for a normal home use for work and leisure. If you need to download large amounts of information from the Internet, for example, torrents, and if you install heavy games, then take a disk with a capacity of 1TB or more. Even larger disks will be useful for those who store large archives. Well, in general, they themselves know why they need such a disk 🙂

I am sometimes asked how many megabytes are in 1 gigabyte, or how many gigabytes are in a terabyte. Everything is simple, but with fun. In fact, there are 1024 bytes in one kilobyte, i.e. 1K=1024B. There are 1024 kilobytes in one megabyte, 1024 megabytes in one gigabyte, and 1024 gigabytes in one terabyte. But manufacturers of rigid discs went for a little trick and took not 1024 as a multiplier, but the number 1000, supposedly so that buyers would not get confused 🙂

Yep, cool! Only now, having installed a drive with a capacity of, say, 500GB, we will see only 465GB available! Because the computer still counts gigabytes as it should!

This is such an embarrassment, so you don’t have to run to give the hard drive back to the store, because now you know how many megabytes are in one gigabyte.

I think it’s clear how to choose a hard drive by volume, but I want to warn against buying a drive with a capacity of more than 2TB. If your motherboard is running a regular BIOS, then you still won’t see more than 2TB! These models require UEFI instead of BIOS. To check this and carefully read its interface and settings in the "Boot" menu. If the word “UEFI” appears, then consider yourself lucky 🙂 Or just read the instructions for the computer motherboard.

But is everything limited by disk space? No, there is another important point - speed.

Hard drive speed

A disk with a large capacity does not yet guarantee fast loading of programs. It just allows you to fit more information. The speed of the hard disk itself is responsible for the speed of downloading programs and their execution. Although, in principle, indirectly, the capacity also affects the speed. Because the larger the volume, the higher the recording density, and, accordingly, it takes less time to read a data block. Simply put, a large disk will almost always be faster than a smaller disk, other things being equal.