What is HDD, hard drive and hard drive. What is HDD? What does the writing on the hard drive mean?

What is HDD, hard drive and hard drive - these words are different widely used terms for the same device that is part of the computer. Due to the need to store information on a computer, information storage devices such as a hard drive appeared and became an integral part of a personal computer.

Previously, on the first computers, information was stored on punched tapes - this is cardboard paper with holes punched in it; the next step in the development of a computer was magnetic recording, the principle of operation of which is preserved in today's hard drives. Unlike today's terabyte HDDs, the information to be stored on them numbered tens of kilobytes, which is insignificant compared to today's information.

Why do you need a HDD and its functionality?

HDD is a computer's permanent storage device, that is, its main function is long-term data storage. HDD, unlike RAM, is not considered volatile memory, that is, after turning off the power from the computer, and then, as a result, from the hard drive, all information previously stored on this drive will certainly be preserved. It turns out that the hard drive serves as the best place on the computer for storing personal information: files, photographs, documents and videos will obviously be stored on it for a long time, and the stored information can be used in the future for your needs.

ATA/PATA (IDE)- this parallel interface serves not only to connect hard drives, but also disk reading devices - optical drives. Ultra ATA is the most advanced representative of the standard and has a possible data usage speed of up to 133 megabytes per second. This method of data transfer is considered very outdated and today is used in outdated computers; IDE connectors can no longer be found on modern motherboards.

SATA (Serial ATA)- is a serial interface, which has become a good replacement for the outdated PATA and, unlike it, it is possible to connect only one device, but on budget motherboards there are several connectors for connection. The standard is divided into revisions that have different data transfer/exchange rates:

• SATA has a data transfer speed of up to 150 Mb/s. (1.2 Gbit/s);
• SATA rev. 2.0 - in this revision, the data exchange speed in comparison with the first SATA interface has increased 2 times to 300 MB/s (2.4 Gbit/s);
• SATA rev. 3.0 - data exchange for the revision has become even higher up to 6 Gbit/s (600 MB/s).

All of the above-described connection interfaces of the SATA family are interchangeable, but if you connect, for example, a hard drive with a SATA 2 interface to a SATA motherboard connector, data exchange with the hard drive will be based on the highest revision, in this case SATA revision 1.0.

The hard 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, this can be games, movies and other large files stored on your PC. And it would be a shame if it could suddenly break down, as a result of which you could 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 a hard drive is.

From this article you will learn about the operation of a hard drive, its components and technical characteristics.

Typically, the main elements of a hard drive are several round aluminum platters. Unlike floppy disks (forgotten floppy disks), they are difficult to bend, hence the name hard disk. 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 replaced without problems.

Figure: Hard drive without top cover

The note!

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

How does a hard drive work?

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

Each side of the disk has its 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

Normal drive operation does not allow contact between the heads and the magnetic surface of the disk. However, if there is no power and the device stops, the heads still fall onto the magnetic surface.

During operation of the hard drive, 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 the rotating surface. A strong impact can cause the head to fail. This output may result in several bytes being corrupted or the device being completely inoperable. For this reason, in many devices the magnetic surface is alloyed, after which a special lubricant is applied to it to cope with periodic shaking of the heads.

Some modern drives use a loading/unloading mechanism that prevents the heads from touching the magnetic surface even if the power is lost.

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 also bypass damaged areas on the disk.

In other words, high-level formatting comes down to creating a table of contents for the disk and file system (FAT, NTFS, etc.). “Real” formatting can only be classified as low-level formatting, during which the disk is divided into tracks and sectors. Using the DOS FORMAT command, a floppy disk undergoes both types of formatting at once, while a hard disk undergoes only high-level formatting.

In order to perform low-level formatting on a hard drive, you need to use a special program, most often provided by the disk manufacturer. Formatting floppy disks using FORMAT involves performing both operations, while in the case of hard disks, the above operations should be performed separately. Moreover, the hard drive undergoes a 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 makes it possible 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, drive C, D or E).

What does a hard drive consist of?

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

disks(their number most often reaches 5 pieces);

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

head drive mechanism(this mechanism sets the heads to the required position);

disk drive motor(a device that causes disks to rotate);

air filter(filters located inside the drive housing);

printed circuit board with control circuits(through this component the drive and controller are managed);

cables and connectors(HDD electronic 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 that is almost never opened. Other components not included in the HDA, which include configuration elements, printed circuit board and front panel, are removable.

Automatic head parking and control system

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

During constant ascents and descents, inevitable abrasion of the magnetic layer occurs. If the drive is shaken after wear and tear, damage to the disk or heads is likely to 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 of the hard drives. This measure prevents the head from touching the magnetic surface even if the power is turned off. When the voltage is turned off, the drive automatically “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 replaceable models used in older generation drives is that they are placed inside the case and are not expected to be replaced until the end of their service life.

Old disks 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 still form after repeated landings and takeoffs of the heads. Taking into account the fact that the drive housing is sealed and air is pumped inside 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 the power source and to the system as a whole. As a rule, the drive contains at least three types of connectors:

interface connectors;

power supply connector;

ground connector.

The interface connectors deserve special attention, since they are designed for the drive to receive/transmit commands and data. Many standards do not exclude the possibility of connecting several drives to one 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 storage devices, which has long been 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 data exchange speed, as well as the emergence of the ability to directly access memory using DMA technology;

Serial ATA- a connector that replaced 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 capabilities.

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

SAS- serial analog SCSI.

USB- an interface that is necessary for connecting external hard drives. Information exchange in this case occurs via the USB Mass Storage protocol.

FireWire- a connector similar to USB, required for connecting an external HDD.

Fiber Channel-interface used by high-end systems due to high data transfer rates.

Hard drive quality indicators

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

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

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 reducing 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 had a capacity of 528 MB.

Even after solving the problems with the BIOS, the capacity limitation of drives with an ATA connection interface remained; its maximum value was 137 GB. This limitation was overcome through the ATA-6 standard, released in 2001. This standard used an expanded addressing scheme, which, in turn, contributed to an increase in storage capacity to 144 GB. Such a solution made it possible to introduce drives with PATA and SATA interfaces, whose storage capacity is higher than the specified limit of 137 GB.

OS restrictions 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.

For example, DOS did not recognize hard drives whose capacity exceeded 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 drive capacity limitation when installing Windows 95. The maximum value for this limit is 32 GB. In addition, updated versions of Windows 95 only support the FAT16 file system, which, in turn, imposes a 2 GB limit on partition sizes. It follows from this that if you use a 30 GB hard drive, it must be divided into 15 partitions.

Windows 98 operating system limitations allow the use of larger hard drives.

Characteristics and parameters

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

The first thing you should pay attention to is the type of interface used. Recently, every computer has begun to use SATA.

The second equally important point is 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 when purchasing a laptop is the hard drive form factor.

The most popular in this case are models whose size is 2.5 inches, while in desktop PCs the size is 3.5 inches.

You should not neglect the spindle rotation speed, the minimum values ​​are 4200, the maximum is 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, measured in revolutions per minute. Its task does not include directly identifying the real exchange speed; 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 use the average and maximum values.

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

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

Internal data transfer rate or the speed of information transmitted from the controller to the heads.

External data transfer rate or the speed of information transmitted via 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 the PATA and SATA interfaces, as well as those running on personal computers with the Windows operating system (from NT to Vista).

S.M.A.R.T. calculates and analyzes the state of connected hard drives at equal intervals of time, regardless of whether the operating system is running 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 S.M.A.R.T. diagnostics, the icon may indicate:

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

The fact that one or more health indicators do not meet the threshold value, while the Pre-Failure / Advisory parameters have a zero value. The above state of the hard drive is not considered pre-failure, 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 hard drive developers, this is a pre-emergency state, and it is not worth storing information on such a hard drive.

Reliability factor

An indicator such as data storage reliability is one of the most important characteristics of a hard drive. The failure rate of a hard drive is once every hundred years, from which we can conclude that HDD is considered the most reliable source of data storage. At the same time, the reliability of each disk is directly influenced by the operating conditions and the device itself. Sometimes manufacturers supply the market with a completely “raw” product, and therefore you cannot neglect backup and completely rely on the hard drive.

Cost and price

Every day the cost of HDD is becoming less and less. For example, today the price of a 500 GB ATA hard drive averages $120, compared to $1,800 in 1983 for a 10 MB hard drive.

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

Hard disk drive (HDD)- is one of the most important components of a computer! And it is the hard drive that most often fails. The result is sometimes the loss of vital information. Therefore, to choose HDD need to be treated with maximum seriousness! In this article, we will look at what there are hard drives, How select hard disk (HDD) for your computer, like avoid problems with information loss and with the help what programs can restore it.

Hard drive size.

Hard drive size (its width is suitable for standard mounts in desktop computers and laptops) is calculated in inches.

Usually for home (stationary) system units use hard drives 3.5 inches (3,5" ).

For laptops- 2.5 inch, respectively - 2,5" .

Connector Type.

HDD connector interface there are two types - IDE And SATA.

IDE- still found in old computers and differs in the number of veins on the train ( 40 And 80 cores, they are interchangeable, differ in throughput speed ).

IDE - connector

SATA- newer, modern interface. Of course higher throughput compared to IDE.

SATA there are three types. SATA(up to 1.5 Gbit/sec), SATA 2 (before 3 Gbit/sec) and SATA 3 (before 6 Gbps) . They differ in data transfer speed.

SATA, SATA2 , SATA3 - interchangeable. But, before you buy a more expensive hard drive with SATA3 , make sure your motherboard supports SATA3, otherwise you will receive an inappropriate expenditure of funds, because... SATA3 HDD connected to interface SATA on an old motherboard, will run at a limited speed up to 1,5 Gbit\sec, without using all your capabilities.

SATA connector

Hard disk capacity.

Quite often computer users confuse the concepts - memory And volume.:) Please remember, the hard drive only has cache memory(we'll talk about it below...).

Volume is the same - capacity! Namely - amount of digital information, which one or another can accommodate HDD. Currently, the hard drive capacity is estimated at Gigabytes (GB) And Terabytes (TB).

For reference: 1 TB = 1024 GB

1 GB= 1024 MB

Disc rotation speed.

A fairly common indicator of HDD speed is disk rotation speed(rpm). Of course, the higher the rotation speed, the louder the hard drive will make noise and its power consumption will increase (this affects its service life). If you are going to purchase a HDD just to store information (an additional disk), in this case, you should not chase speed. I advise you to choose a faster hard drive if you install the Operating System on it. At the moment, 7200 rpm is the most the best option.

Cache size.

Cache memory(buffer) - this intermediate memory. It is designed to increase the speed of the hard drive while accessing its data. IN "cache" are storedresponses to the most frequent system and application requests.And of course, there is no need to constantly read information from the disk itself. this increases the efficiency of the HDD and the system as a whole. The size of the "cache" in modern hard drives usually varies from 8 before 64 Mb.

Company manufacturer.

At the moment, the main manufacturers of hard drives are - Western Digital, Hitachi, Samsung, Seagate Technology, Toshiba. You can argue to your heart's content :) which company is better... But let's look at the facts. Let's type in an intelligent search engine Nigma.ru "hard drive problem....."(instead of dots we write the company):

hard drive problemHitachi- requests 5 400 000.

hard drive problem Seagate- requests 5 500 000.

hard drive problemWestern Digital - requests 7,400,000 .

hard drive problemSamsung - requests 17 000 000.

As you can see, first place in reliability goes to Hitachi, second Seagate. Although, based on my own experience, I would put it in second placeWestern Digital (WD).

W.D. come with stickers of different colors - Black(black), Blue(blue), Green(green). Considered the most reliable Black, In second place Blue and at the last Green.

So, when choosing a hard drive:

1. Important! You need to find out - what connector on your old hard drive. If IDE, then I advise you to look at the connectors on the motherboard. In the presence of SATA- connections, it's better to buy SATA hard drive. With absence SATA buy IDE.

2. Important! Find out whether your old power supply will handle the new one (perhaps more voluminous and speedy) HDD.

You can find out how to do this by watching the video tutorial.How to choose the right Power Supply!

3. Decide on Volume(number of GB), Speed(rpm) and "Keshem"(8-64MB) hard drive.

4. Choose manufacturing company.

How to avoid problems with information loss.

1. Keep a backup copy of data on removable media.

How does a hard drive work? What types of hard drives are there? What role do they perform in a computer? How do they interact with other components? You will learn from this article what parameters to consider when choosing and purchasing a hard drive.

HDD- shortened name for " Hard Disk Storage". You will also find English HDD- and slang Winchester or for short Screw.

In a computer, the hard drive is responsible for storing data. The Windows operating system, programs, movies, photos, documents, all the information that you download to the computer is stored on the hard drive. And the information on the computer is the most valuable! If the processor or video card fails, you can buy and replace them. But lost family photos from last summer's vacation or a year's worth of accounting data from a small business are not so easy to recover. Therefore, special attention is paid to the reliability of data storage.

Why is a rectangular metal box called a disk? To answer this question, we need to look inside and find out how the hard drive works. In the picture below you can see what parts the hard drive consists of and what functions each part performs. Click to enlarge. (Taken from the site itc.ua)

I also suggest watching an excerpt from a Discovery Channel program about how a hard drive works and works.

Three more facts you need to know about hard drives.

1. The hard drive is the slowest part of the computer. When your computer freezes, pay attention to the hard drive activity indicator. If it blinks frequently or lights up continuously, it means the hard drive is executing commands from one of the programs while all the others are idle, waiting their turn. If the operating system does not have enough fast RAM to run a program, it uses up space on the hard drive, which greatly slows down the entire computer. Therefore, one way to increase the speed of your computer is to increase the size of RAM.
2. The hard drive is also the most fragile part of a computer. As you learned from the video, the engine spins the disk up to several thousand revolutions per minute. In this case, the magnetic heads “float” above the disk in the air flow created by the rotating disk. The distance between the disk and the heads in modern devices is about 10 nm. If the disk is subjected to shock or vibration at this time, the head may touch the disk and damage the surface containing the data stored on it. As a result, the so-called " badblocks" - unreadable areas, due to which the computer cannot read any file or boot the system. When turned off, the heads are “parked” outside the working area and shock overloads are not so terrible for the hard drive. Please make backup copies of important data !
3. The hard drive capacity is often slightly smaller than what the seller or manufacturer indicates. The reason is that manufacturers indicate disk capacity based on the fact that there are 1,000,000,000 bytes in one gigabyte, while there are 1,073,741,824 of them.

Buying a hard drive

If you decide to increase the storage capacity of your computer by connecting an additional hard drive or replacing the old one with a larger one, what will you need to know when purchasing?

First, look under the cover of your computer's system unit. You need to find out which hard drive interface the motherboard supports. Today the most common standards are SATA and moribund IDE. They are easy to distinguish by their appearance. The picture on the left shows a fragment of a motherboard that is equipped with both types of connectors, but yours will most likely have one of them.

There are three versions of the interface SATA. They differ in data transfer speed. SATA, SATA II And SATA III at speeds of 1.5, 3 and 6 gigabytes per second, respectively. All interface versions SATA look the same and are compatible with each other. You can connect them in any combination, which will result in data transfer speeds being limited to the slower version. At the same time, the speed of the hard drive is even lower. Therefore, the potential of fast interfaces can only be revealed with the advent of new high-speed drives.

If you decide to purchase an additional SATA hard drive, check whether you have an interface cable like the one in the picture. It is not sold together with the disc. (They are usually included with the motherboard.) Also, among the power supply connectors there should be at least one free for connecting a hard drive, or you may need an adapter from the old standard to the new one.

Now about the hard drive itself: The main parameter is, of course, capacity. As I mentioned above, keep in mind that it will be slightly less than stated. The operating system and programs require 100 - 200 Gigabytes, which is quite a bit by modern standards. How much additional space you may need can be determined experimentally. Large volumes may be required, for example, to record high quality video. Modern films in HD format reach several tens of gigabytes.

In addition, the main parameters include:

1. Form factor- disk size. Discs of 1.8 and 2.5 inches are used in . For a desktop computer, you should purchase a 3.5-inch drive. They have the same SATA connectors and the laptop drive can work in a desktop computer. But small disks are made with an emphasis on compactness and low power consumption, and are inferior in performance to larger models. And they cost more.
2. RPM- disk rotation speed. Measured in revolutions per minute ( RPM- abbreviation for revolutions per minute). The higher the rotation speed, the faster the disk writes and reads information. But it also consumes more energy. Today the most common disks are with 5400 RPM And 7200 RPM. Lower RPMs are more common in laptop drives, high-capacity drives (more than two terabytes), and so-called “green” drives, so named because of their reduced power consumption. There are also hard drives with rotation speeds 10000 RPM And 15000 RPM. They are designed to work in highly loaded servers and have an increased reliability life, but they are also much more expensive than regular ones.
3. Manufacturer. There are currently several large manufacturers on the storage drive market. There is quite tough competition among them, so they are in no way inferior to each other in quality. Therefore, you can choose any of the well-known names: Hitachi, HP, Seagate, Silicon Power, Toshiba Transcend, Western Digital.

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

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

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

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

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

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

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

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

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

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

2. Disk types

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

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

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

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

3. Application of HDD, SSD and SSHD drives

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

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

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

4. Physical sizes of disks

Hard drives for desktop computers are 3.5 inches in size.

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

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

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

5. Hard drive connectors

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

5.1. Interface connector

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

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

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

5.2. Power connector

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

6. Hard drive capacities

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

6.1. Hard disk capacity (HDD) for a computer

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

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

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

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

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

6.2. Hard disk capacity (HDD) for a laptop

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

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

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

6.3. Solid State Drive (SSD) Capacity

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

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

For a multimedia computer (movies, simple games), the best option would be an SSD with a capacity of 120-128 GB, which will allow, in addition to the system and basic programs, to install several simple games on it. Since an SSD requires more than just quick opening of folders, it makes sense to install the most powerful programs and games on it, which will speed up their operation.

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

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

6.4. Data backup

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

7. Basic disk parameters

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

7.1. Spindle speed

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

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

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

7.2. Memory Buffer Size

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

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

8. Disk speed characteristics

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

8.1. Linear reading speed

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

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

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

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

8.2. Linear write speed

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

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

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

8.3. Access time

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

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

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

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

9. Manufacturers of hard drives (HDD, SSHD)

The most popular hard drive manufacturers are the following:

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

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

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

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

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

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

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

10. Manufacturers of solid state drives (SSD)

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

• Samsung
• Intel
• Crucial
• SanDisk
• Plextor

More budget options can be considered:

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

11. Memory type SSD

SSD drives can be built on different types of memory:

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

12. Hard drive speed (HDD, SSHD)

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

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

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

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

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

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

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

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

13. Optimal disk

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

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

14. Cost of HDD and SSD drives

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

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

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

15. Links

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