Hard disk or HDD - data storage device. Before the appearance of solid-state drives (SSD), it was used to install the system, and to place custom files. Despite competition from more advanced technology, HDD continues to be an important element of the computer. To properly use the drive and extend its performance, you need to know what it consists of things and how it works.
Basics of design
The composition of components in the most common features is already revealed in full name - the drive on rigid magnetic disks. But this is a greater degree description of technology, and we will start with an elementary - physical device of the carrier. If you take it in your hands and twist, you can quickly allocate two parts:
- Control board - serves to connect a disk to a computer, manuals all processes inside HDD and synchronization with an operating system.
- The sealed block - assembled from aluminum housing, inside which the remaining components of the hard disk are located.
This is a very general classification that does not say anything about how everything works. To sort out the details, deeper into the disassembly of the drive.
Let's start with the study of the board. In the very center of the scheme there is a large chip - microcontroller (MCU). It consists of two components:
- The central computing unit - performs all calculations.
- The reading and writing channel is a device that translates an analog signal from the head into a discrete and vice versa - from a digital signal to analog.
The microprocessor also has an input / output ports through which it controls the other elements in the board and communicates through the SATA interface used to connect to the motherboard.
The second chip that we detect on the board - DDR SDRAM memory. The amount of accessible cache on the disk depends on its volume. The chip is divided into firmware memory, which is partially contained in a flash drive, and buffer memory used by the processor to load the firmware.
The third chip is the engine and head control controller (VCM Controller). It is also responsible for the operation of additional power sources located on the board. They receive the energy of the microprocessor and the preamp switch - the element from the hermetic block, which we will talk about below. VCM Controller consumes more energy than other components, because it is engaged in rotating the spindle and move the heads.
The diagram also has a vibration sensor that monitors the layer level. If the intensity seems dangerous to him, then it sends a signal to the controller of the engines and heads with the requirement to immediately park the heads or stop the rotation of the HDD. Theoretically, this should protect the disk from mechanical damage, but in practice it often leads to the fact that the drive fails. If you drop it, the sensors begin to react to the slightest vibration and block the work of the carrier.
HDD protection is also engaged in a transitional voltage limiter. His task is to prevent the disk from the output when the voltage jumps. Such limiters on the board may be several.
The device is simple, but very functional. Each element performs its task and provides a common relationship between all components of the hard disk.
Hermobal is not just a box in which magnetic discs are stored. The surface of this component also performs extremely important tasks. If we unscrew the control board, we will see contacts from motors and heads under it. They communicate with the board. Next to them is an almost invisible technical hole, whose task is to align the pressure inside and outside the hermetic box. The inner part of the hole is covered with a filter that does not let moisture and dust in the magnetic disc storage.
The lid of the hermetic unit on the other hand is a metal reservoir with a rubber gasket that protects the insides from dust and moisture. We remove it and see magnetic discs - they are also called pancakes and plates.
Discs are usually made from glass or pre-polished aluminum. Plates are coated with layers of different substances, including a ferromagnet. It is thanks to him that we get the ability to record, store and read data. Above the top pan and between the other plates are separators. They level the air flow and reduce the noise level. Separators are usually made of plastic or aluminum - the latter are better coping with a decrease in temperature inside the hermetic zone.
Block of magnetic heads
One of the most complex devices in the hard disk has a block of magnetic heads (BMG). Consider all the items that it contains. Let's start with writing heads - they are located at the ends of the brackets. When the spindle is stopped, the heads should be located in the preparation area - this is a specially dedicated place, which is involved if the shaft does not work. On some HDD, the transparent areas are outside the plates.
The normal functioning of the drive requires clean air with minimal content of foreign particles. Circulation filters are installed inside the drive to provide such an atmosphere. They remove particles of lubricant and metal that are assembled in the Hermokorpus during the work of the HDD. Filters are on the path of air flows appearing during the rotation of the plates.
An important part of the hard disk is neodymium magnets. They are capable of attracting and retaining weight, which is more of their own 1300 times. In HDD, magnets limit the movement of the heads by holding them over pancakes.
Another part of the magnetic head unit is a coil. Together with the magnets, it forms a drive that is part of the positioner - the device moving the head. Positioner also has a lock. It frees the magnetic head block as soon as the spindle is gaining the speed of revolutions. For release, air flow is also used.
Under the magnetic head unit is the bearing, which provides smoothness and accuracy of movements. Immediately the rocker is the part of the aluminum alloy, at the end of which heads are located with spring suspensions. A flexible cable is conducted from the rocker in the contact pad - it connects the mechanical part of the hard disk with an electronic board.
For hermetic clutch uses a gasket. Due to it, air falls inside the housing only through the process opening, which levels the pressure level. Contacts are covered with the finest gilding, which improves conductivity.
At the ends of the rocker there are spring suspensions. They have sliders who help to write and read the data by lifting the head over the plates by 5-10 nm. The read / write elements themselves are located at the ends of the sliders. They are so small that you can only see them through a microscope. These parts have aerodynamic heads under which an airbag appears that supports the parallel surface of the flight.
A preamp is also responsible for managing heads. It is in BMG. Without an amplifier, a signal that produces magnetic heads, simply would not reach the integrated circuit, scattered along the way.
The microprocessor sends requests to the preamp so that he selected the appropriate head. From the disk to each of them there are several tracks. They are responsible for reading and recording, grounding, drive management, the operation of magnetic equipment, which manages the slider to increase the accuracy of the heads. One of the tracks leads to the heater.
The heater transmits heat to the suspension connecting the slider with a rocker. The suspension is made of materials whose expansion parameters vary depending on the temperature. With increasing temperature, it bends in the direction of the plate, reducing the distance from it to the head. When the temperature decreases, the reverse reaction occurs - the head moves away from the disk.
For fastening the plates, a pressure ring is used. The pancakes themselves are risen on the shaft. In order for the heads space between them, the dividers are used, which we have already spoken above.
At the day of the hermetic block there is a space for leveling pressure with the most imperceptible hole. Here we find another filter, which is much more than circular filters. It can be covered with a silicate gel gathering moisture, which still managed to break through the inside of the housing.
As you can see, the hard disk device is quite complex and fragile. Therefore, it is so sensitive to mechanical exposure. Damage to the vibration sensor or the magnetic head unit leads to the fact that it becomes unrealistic to write and read the information. It is possible that that is why HDD is universally replaced by SSD, which offers higher speed and resistance to mechanical effects.
Material author: Sergey Cowlene
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Changed in the 80s of the last century drives on flexible discs and completely archaic chapels with perflectors, HDD ("Hard Disk Drive" - "hard disk drive") for a long time have become the main device for storing programs and data on most computers. True, recently, they slowly pass positions:
SSD is much superior to HDD in speed, the price difference every year is less and less, so, perhaps, another 5-10 years and hard drives will go down in history after flexible discs and CD-ROM-AMI. But this has not yet happened and there is at least two weighty reasons to prefer the HDD:
- They are still much cheaper: the average SSD is 8-9 times more expensive than the average HDD of a similar container;
- SSD has a limited number of recording cycles - for a home computer is not as critical, but for many HDD server solutions will ensure greater reliability of data storage.
Title This type of drives received due to its design - information is stored in one or more hard disks with ferromagnetic coating. Data access is provided by magnetic heads moving on a small (about 0.1 MK) distance from rotating disks.
HDD is available in two form factors: 3.5 "and 2.5". Compared with the latter, 3.5 "HDD has a greater maximum volume and a smaller price in terms of gigabytes. If the low price is not as important to you as compactness, speed and less power consumption, then you better pay attention to 2.5" HDD. There are hard disks of other form factors (1.8 ", for example), but they are usually used in the special equipment and their volume is small.
Deciding with the form factor, do not hurry with the purchase - hard drives have a multitude of characteristics that determine their effectiveness in certain conditions of use.
Hard disk characteristics
Volume HDD. - its main parameter that has the greatest impact on the price of the device and its attractiveness for the buyer. Requirements for programs to the free space on the disk are constantly growing, as well as the volumes of video files and files with photos, so the desire to purchase a large-volume drive is quite understandable. On the other hand, the HDD of a large volume is more expensive than another computer. What volume disc choose?
As can be seen from the graph, the smallest price for gigabytes has 3-6 TB discs. Looking down to a 10 TB disc and more, check whether there will be a more profitable purchase of two smaller disks? And a gigabyte volume is completely expensive when buying disks in 1TB and less.
When buying an HDD capacity of more than 2 TB, make sure that the SATA-controller of your computer's motherboard supports hard drives with a volume of more than 2.2 TB, and that you have a GPT support operating system (GUID PARTITION TABLE - a new hard disk partition table, capable of addressing more than 2 TB). GPT support is implemented in Windows Starting from version 7, in Mac OS from version 10.6 and in all modern Linux distributions. If some of these two conditions is not executed, you will not be able to use more than 2.2 TB of your new HDD.
If you want the download also made from a new hard disk, the motherboard must have a UEFI BIOS. All modern motherboards support large-sized discs, difficulties may occur only with "motherboard" released until 2011.
Spindle rotation speed It has a direct impact on the speed of reading and writing data from the hard disk. High-speed discs on average have a greater data transfer rate than low-speed, but also more noisy and consume more energy.
However, it is not necessary to compare disks of different manufacturers only on this parameter: the read / write speed depends not only on the speed of spindle rotation, but also on the positioning speed of the heads, from the hard disk controller circuitry, etc. Therefore, if you are important than the speed of data access, it is better to pay attention directly to the speed characteristics.
Maximum data transfer rate It is the maximum achievable read / write speed on this model. This speed is achieved only under certain conditions; in normal operation, such velocities are achieved only when rewriting non-nephomy (consisting of the blocks of blocks sequentially located on the disk); Ordinary speeds will be much smaller.
If the use of the disk involves working with a large number of small files, it is worth paying attention to Average access time и Average delay time "The smaller these parameters are, the faster the disk head is positioned on a new file and the faster will be working with small or fragmented files.
The filling of the disk helium allows you to reduce the aerodynamic effects that slow down the rotation of the disks and leading to vibration. As a result, Helic hard drives Have less power consumption and less noise compared to conventional air filled - this is especially important for high-speed HDD. It also allows you to reduce the thickness of the disks, which leads to an increase in speed and volume (due to the larger number of disks in HDD).
However, such HDDs are more expensive than conventional and very demanding to the quality of manufacture - with a violation of the tightness of helium, it is rapidly "drowning" from the housing, and the discs are not intended for work in an air atmosphere quickly come into disrepair.
Purpose The hard disk specified by the manufacturer can help in choosing, but it is not necessary to rely on it, since there are no clear criteria by which you can unambiguously determine the assignment of HDD. In addition, sometimes the indication of some destination is simply marketing trick.
However, you should pay attention to this parameter when the hard disk operation mode differs from the usual one. For example, if an HDD is continuous 24-hour recording (video system) or it works around the clock with a strong load, constantly performing recording and reading operations (server).
If the disc is purchased for installation in the RAID (array of hard disks of increased storage reliability), also pay attention to Optimization under the RAID array .
An ordinary hard disk when you try to read from a failed cluster, repeats this attempt several times trying to restore the data. The HDD of the RAID Edition type does not repeat the reading attempt, and immediately reports the RAID controller about the "dubious" cluster - this avoids the drop in performance when failed areas appear on one of the solutions of the array.
NCQ support Also can speed up the work with the disk in some cases - HDD with NCQ support is capable of optimizing the queue queue to the disk. For example, if there are several positioning / reading commands in the queue, the hard disk controller ordered this queue so as to minimize the movement of the head.
The amount of cache memory. Cache memory is used to buffer data: before recording to the disk, the data is placed in it, and if they need a computer in the near future, they will be read not from the disk surface, but directly from the cache memory, which, of course, is more quickly. The presence of cache memory significantly speeds up working with hard disk data, especially with frequently used - indexes, boot records, file posting tables, etc.
The amount of cache memory affects the speed of operation slightly - the minimum cache volume for modern hard disks is quite enough to store service information on the disk. However, if the use of a disk involves working with frequently using small files (system disk, server disk), then it is better to choose a more model with a cache - this will increase the likelihood that the desired file will be in the buffer and access to it will be done at times faster. If the disk is used to store the files of a large volume, the size of the buffer on the performance of particular influence will not be available.
Hybrid SSHD drive As a second-level cache uses a solid-state disc with a volume of several GB. Since the data reading speed with SSD is much higher than with HDD, it gives an increase in performance if frequently used data are located on the disk. Such discs can be used as systemics, you can have work programs and databases - this will give a noticeable performance increase.
Interface. Modern data transmission discs are used either SATA third generation, or server SAS. HDD SATA can be connected to the SAS controller, and vice versa - no.
Interface bandwidth SATA III and SAS Various - the first gives a maximum of 6 Gb / s, the second - 12.
On the Noise level during operation and B. Simple Attention should be paid if the disc is purchased for a home computer or if you do not like foreign sounds while working. Some discs create when working noise level up to 36 dB - this can be compared with the loudness of a calm conversation.
The fact that hard drives are "afraid" of blows and vibrations - the fact is well known, but somewhat exaggerated - for the HDD computer enshrined in the case is not as important as for external hard drives. Most HDDs are capable of carrying out a drop on a solid surface from height 1 "( Accessibility 40g) During operation and from a height of more than a meter - in the off state. If your computer is experiencing more serious loads, choose among models with a greater impact resistance.
Hard disk selection options
If you want to purchase a hard drive at the lowest price, keep in mind that the HDD is 0.5 TB, although it is cheaper, but the gigabyte volume will cost you much more expensive than the hard disk of greater capacity. It is better to pay a little and purchase a 1 TB disc or more.
If you wish to get a maximum of a minimum of money, choose among hard drives for 3-6 TB - in this range the price of the gigabyte volume is the lowest.
By buying a HDD of a large volume, you will for a long time forget about the disadvantage of the disk space.
If you select a hard drive for a server or video system, choose among models with the appropriate purpose.
The RAID array is able to ensure the preservation of data even with the full destruction of one of the hard drives included in it. HDD is designed to create it with optimization under the RAID array.
When discussing computers, such terms as hard disk, hard drive or HDD are not rarely used. These terms indicate one of the main components of the modern computer, which is used to store all user data. In this article, you will learn what a hard drive is why it is called hard drive, as well as how to choose this component.
What is a hard drive
What does the hard disk look like without a lid.
Hard disk is a data storage device that works on the basis of a magnetic record. In this device, the data is written on a layer of ferromagnetic material applied to the surface of an aluminum or glass disk.
The hard disk uses one or more such discs that are fixed on the total axis. During the operation of the device, these discs rotate at high speed (5400 revolutions per minute or more), and the magnetic head is located above the disk, which reads and records information to the disk.
Hard disk is a fairly sensitive device. In the event of a large overload, for example, due to impact, it can easily fail. This vulnerability is particularly relevant during the operation of the device. This is due to the fact that when producing a hard disk, minimum tolerances are used. For example, the distance between the reading magnetic head and the surface of the disk, which rotates during operation, is only 10 nanometers.
Now hard disks are gradually displaced by solid-state drives (SSD). Unlike hard drives, solid-state drives do not have moving parts and thanks to this much reliable, they are not so afraid of shocks and overloads. In addition, solid-state drives work much faster. This allows you to quickly turn on the computer and run programs.
On the other hand, the cost of storage of 1 gigabyte data on the SSD drive is much higher. Thus, the hard disk on 1 terabyte is now worth about $ 50, while 1 terabyte on SSD is worth not less than $ 200. Therefore, hard drives are still a major device for long-term storage, manufacturers of desktops and laptops continue to embed them into their devices.
But, over time, the cost of solid-state drives will decline and at some point they will completely replace hard drives. Now SSD is most often used in a pair with a hard disk. The SSD drive records the operating system and programs, and the user files to the hard drive.
What is Winchester
What does the hard drive look like.
The hard disk has several alternative names. For example, the HDD abbreviation is not rarely used for its designation, which is decrypted as Hard Disk Drive, which can be translated as a hard disk drive. Another possible name is Winchester. This is an unofficial slang name, which appeared in the 70s.
According to one of the versions, the hard disk began to be called the Winchester due to IBM employees, which developed a hard disk of the model 3340. When creating this device, the engineers used the "30-30" brief designation. This designation indicated that the hard disk consisted of two modules of 30 megabytes. At the same time, it coincided with the name of the rifle cartridge .30-30 WINCHESTER for the popular rifle Winchester Model 1894. Because of this coincidence, the hard disk and began to call the hard drive.
Such a name was well stuck and was widely used until the end of the 90s. Later, it began to go out of use. Now in the USA and Europe, a hard disk is no longer called Winchester, but in the CIS countries it is still used.
Choosing a hard disk
In order not to make a mistake with the choice of hard disk it is important to clearly understand what this disk will be used. First, you need to decide on the type of hard disk. Now there are external and internal hard drives. External hard drives usually have a protective housing and a USB interface that allows you to connect this disk to a computer as a conventional flash drive. This type of discs is usually used to transfer or backup data. Internal hard drives are usually equipped with the SATA interface and are meant to install inside the computer.
And secondly, you need to choose the form factor. Modern discs are available in two versions: 2.5 and 3.5 inches. 2.5 inch versions are installed in laptops, and 3.5 inch to desktop computers. External hard drives can also be both at 2.5 and 3.5 inches. External discs by 2.5 inches are more compact and do not require additional nutrition, while external discs by 3.5 inches offer more volume for the same price.
After you have determined with the type and form factor of the hard disk, you can look at the volume and other characteristics. For example, such characteristics are very important as the speed of rotation of the spindle and the amount of cache. What they are higher, the faster the drive will work. The manufacturer of hard drives is also important, now the highest quality models are released by Western Digital and Seagate.
Hard disk (HDD) is one of the basic elements of any computer. It is he who is responsible for storing all the information - from the operating system to individual user files. In recent years, classic hard drives are displaced more reliable, but also more expensive solid-state drives (SSD), but they are performed in the same form factor and serve as functions. Therefore, the information outlined here is applicable to both types of data warehouses. We will tell how to remove them from the computer and what rules at the same time must be observed.
How to remove a hard drive from a computer
About sizes, location and interfaces
To remove a hard drive, you need to know how it looks, where it is located, what is both connected. Experienced computer users can skip this section for the rest - a small theoretical base.
The specifics of the hard disk operation requires its protection against unnecessary vibrations, as well as the impossibility of free movement of the part in the computer's system block. Therefore, HDD is usually installed in a special pocket equipped with two guides, and fixed in it with bolts or clamps.
Note! Although SDD is less demanding on the mechanical stability of work, it is usually placed ibid. Pocket from most system blocks is located in the front bottom.
Fastener location for hard disk
Externally, a hard disk is a rectangle with a standard 2.5 or 3.5-inch width (70 or 102 mm) corresponding to the width of the mounts. More often meet other form factors. Standard sizes have official names: Small Form Factor (SFF) and Large Form Factor (LFF). Thickness can vary within 7-15 mm.
Hard disk thickness has differences
The hard disk has a all-metal or semi-closed metal case, solid-state drives are supplied in aluminum or plastic housings. The rear end panel has data exchange interfaces. They are two species:
- IDE (ATA) - was massively used in from the 1990s to the 2000s, it is easily recognizable due to a wide 40-wire loop with a rectangular plug;
- SATA is a modern high-speed interface, much thinner of its predecessor and has only seven contacts hidden under the plug hooded.
As can be seen in the figure, the form of a four-contact power plug of hard drives with IDE and SATA interfaces is also different.
Distinctive features of plugs
Data exchange tires connect hard drives or solid-state drives with a computer motherboard. Well, the necessary electricity components required to work directly from the power supply by the standard four-wire branch.
Disconnection and removal of PC drives
The hard disk dismantling can be carried out for various reasons: to diagnose the part, cleaning the system unit, replacing the faulty or obsolete disk to the new one.
Important to remember! After removing the HDD or SDD from the computer, all the data stored on it will be unavailable, and if the operating system is installed on this drive, the PC will not turn on until the disc return is in place.
Works are performed in such a sequence:
- Turn off the computer and take the power cord from the power supply. Give the system unit to stand 10-15 minutes. This time will be enough that the mechanical elements of the HDD stop rotating, the parts heated during operation were cooled, and the capacitors gave residual charge.
Turn off the power cord from the power supply
- Find on the rear end panel of the system unit bolts fastening the right side cover and unscrew them. To remove the lid, move it back and pull on yourself. Act care not to damage the wires. If any electronic elements are located on the lid (fan, cooler, backlight, control buttons), slightly open the lid and remove the plugs from the corresponding nests on the motherboard.
Unscrew the fastening bolts
- Disconnect the power cord, and then the data exchange loop from the corresponding hard disk connectors. Do not pull the wire - it can damage the interface contacts. Girth with your fingers plastic rim connector and pull.
Turn off the power cord, and then the loop exchange loop
- Unscrew two bolts of fastening the hard disk and pull it on yourself. Note that instead of bolts, spring or sliding clamps can be installed to be installed in the free position.
Unscrew the hard disk mounting bolts
- Remove the drive from the pocket. If it does not give in, remove the left cover - sometimes the part is fixed from both sides for more reliable fixation. In this case, you will have to unscrew the screws or weaken the clamps and on the other hand.
This dismantling hard disk completed. Installation is performed in reverse sequence.
Disconnection and removal of drives on a laptop
All stationary system blocks are arranged almost equally. There are differences in size, the location of some elements, fastening types, but not in the basic block configuration. Therefore, remove the hard disk with the PC is relatively easy. It is much more difficult to work with laptops, because each manufacturer in pursuit of compactness develops its own device layout scheme.
Find and remove the hard drive on the laptop
Note! First of all, carefully inspect the bottom cover of the laptop. It can be general or consist of several parts.
The second case is preferable, as it allows you to get direct access to the hard disk through a special window. In the same case, when the entire lower surface of the gadget is closed with a common lid, you will have to slightly "freeze" with the search for the drive and the release of the road to it. Consider the overall method of dismantling HDD or SDD from a laptop on an example of a device with separate lids.
- Turn off the laptop, disconnect the power connector and all other cords from it. Close the laptop and turn the bottom cover up, then remove the battery (it is usually fixed by one or two sliding snaps). Leave the gadget for 10-15 minutes.
Take out the battery
- Unscrew the screws that lock the hard disk compartment cover. In the case of a common lid at this stage, unscrew all the screws. It is better to immediately remove them in a safe place - in view of the small sizes of the screws, they are very easy to lose.
We unscrew the screws that lock the hard disk compartment cover
- Under the lid there is a metal basket, inside which is placed a disk drive. The basket has several ears (usually four), which are fixed on the laptop frame with screws. Unscrew them. Remember that these screws may differ from the screw mounting screws with dimensions and threads, so put them separately.
Remove the screws
- Patty the plastic basket tongue, pull it first aside to disconnect the hard drive from the data exchange bus and power connector, and then up to remove the basket of the pocket.
Disconnect the hard drive from the data and power connector tire
- Unscrew the four screw mounting screws located on the side surfaces of the basket. They are also incompatible with cover screws. Now the hard drive is released from all auxiliary elements.
We unscrew the four drive screws on the side surfaces of the basket
This dismantling hard disk completed. Installation is performed in reverse sequence. Threaded compounds, and especially the fastenings of the lid, it is better to strengthen with a small amount of sealant.
Read interesting information in the new article - "How to delete a disk with from a computer."
Nuances connect incompatible hard drives
Sometimes you need to connect the hard disk of the computer to the laptop or vice versa. Due to differences in the form factors of products or interface types, a number of problems may arise, which, however, are solved very simply. Follow these tips, and you will succeed:
- To connect the hard disk with the IDE interface to the SATA motherboard, use a special adapter, it also allows the back sequence of the part of the part;
Hard disk adapter
- To install a 2.5 standard hard disk to the housing, supporting the form factor 3.5 will need a magnifying pocket, which can be purchased at any large store of computer components;
Magnifying hard disk pocket
- Any hard disk can be connected to a laptop or PC using the USB interface, if you use a special adapter and provide an external power source (this board is commemorating first of all to those who need to use a 3.5-inch laptop drive);
Special adapter for connecting hard disk
- If for any reason you do not have the ability to secure the hard disk in the device housing, provide it with maximum protection against vibrations and mechanical shocks, for example, put a soft lining into a free niche of the system unit, and fix the part of the part with cardboard struts (however, do not forget that the hard drive is heated during operation and requires sufficient heat exchange with the environment through the surface of the housing), remember that the wires and loops should not be excessively tensioned;
Reliably fix the hard drive in the case of the device
- In system blocks or servers with multiple hard disks, located close to each other, it is necessary intensive air cooling of the entire inner surface of the case, otherwise the overheating of the drives is inevitable; In addition, there are pockets for HDD with compulsory cooling.
Air Cooling for Hard Disk
Remove the hard drive, replace it or install an additional drive is difficult only at first glance. Follow the instructions outlined here, be careful and careful, and you will definitely work out!
Video - how to remove a hard drive from a computer
Did you like the article? Save not to lose!
To lose anything, I stored files on different hard drives.
Stores information immediately on five hard drives
One is needed that "Windows" loaded in a few seconds. The second is slightly slower, but the volume is on it, I keep movies and music archive. Third disc only for work. And two more external disks, on which I storing what I did not fit into the rest.
Such a separation is convenient: if the operating system breaks, you do not have to restore working files, because they are stored on another physical disk.
What we call a hard disk
"Hard disk" is a device on which we store files and programs. Previously, there was only one type of such devices - HDD. Then the solid-state drives were added - SSD, but many of the habit and they are called hard drives. In this article, I tell about all the main types of data storage devices.
I will tell you how to choose a hard disk without sellers of sellers and so that it is not confused.
HDD or SSD.
These are two different types of drives. That's what they differ.
HDD. (Hard Disk Drive - "Hard Disk"). The principle of operation is based on a magnetic record. Inside the case placed discs made of a special mixture of metal and glass with spraying from above. Information is recorded on the top layer - in fact, in the same way as on vinyl records. Technology non-volatile: information remains on the disk and without the connection of electricity.
HDD has a big minus - fragility. A sufficiently small impact, and the disks will move from the place, the spraying is damaged, and the data will be lost. Therefore, HDD or is used inside the system unit or laptop, or placed in a special case and are treated superior. But there is a small opportunity to restore the data even with a partially defective disk.
SSD. (SOLID-STATE DRIVE - "Solid State Drive"). Such a disk consists of a controller and a set of microcircuits on which information is stored.
The smallest elements inside the microcircuits take the value "1" or "0". The processor reads these values and converts them to our usual files: documents, pictures, video. SSD can be compared with advanced and bulk flash drive.
The minuses of SDD are usually called the price and capacity: it is difficult to find a SDD with a volume of more than 2 TB. And such discs are usually more expensive than HDD.
Sshd. (SOLID-STATE HYBRID DRIVE - "Hybrid Hard Disk"). This device in which the data is stored on the disks, and flush memory.
Such devices increase computer performance due to special architecture: they write down on the SSD part Disk information that is needed to load the operating system. During the next enable computer, the system will start working faster, because its data is located on a quick part of the disk.
Moments such devices work faster, but essentially remain the same HDD with all their disadvantages.
For example: 💾 HDD hard drive for 1 TB - Seagate for 4036 Р💾 SSD Solid State Drive for 500 GB - Samsung for 5299 Р💾 SSHD Hybrid Hard Drive for 2 TB - Seagate for 10 490 Р
External or internal disk
The drives can be installed inside the computer or laptop or simply carry with them as a flash drive.
Internal hard drives Placed inside the system unit or laptop. Here is important Form factor - What size and form will be a hard drive. It is usually indicated in inches.
For example, if you buy a hard disk for a regular system unit with a width of 2.5 inches, you will have to think where to put it: standard mounts are designed for 3.5 inches wheels. In laptops usually use Form factor 2.5 - A greater width disk you just do not shove.
Some manufacturers measure discs not in inches, but in millimeters. They write like this: 2242, 2262 or 2280 mm. The first two digits mean the length of the disk, the last two - width. Such Form factors Used for SSD.
Before you choose an internal hard drive, check what you need Form factor , In the instructions for a computer or laptop. Or just look at the characteristics of the existing hard disk.
To connect an internal disk, you need to turn off the computer or laptop, remove the cover, find the desired connectors for data exchange and power, connect the device.
For example: 💾 Internal HDD for system unit with form factor 3.5 - Seagate for 3669 Р💾 Internal HDD for a laptop with form factor 2.5 - Toshiba for 3904 Р💾 Internal SSD with Form Factor 2280 - A-DATA for 11 990 Р
external HDs can be worn with you so from form factor Only convenience depends on. I calmly use a big disc 2.5 inches, and someone Prefers miniature by 1.8 inches.
External discs most often use USB connectors , Therefore, to connect them, you just need to insert the wire into the desired slot - as a flash drive.
For example: 💾 External HDD with Form Factor 2.5 - Toshiba for 3799 Р💾 External SSD with Form Factor 2.5 - Samsung for 7599 Р
This term is indicated how the computer is connected to the computer - this is a physical connector, and a data transfer method. Modern several.
SATA interface - The main standard for connecting hard drives. There are three generations of such connectors, they differ mostly throughput:
- SATA 1: 1.5 gigabit per second. In ideal conditions, the film weighing 8 GB is almost per minute.
- SATA 2: 3 Gigabit per second. The film should have enough 30 seconds.
- SATA 3: 6 Gigabit per second. The film is downloaded in 10 seconds.
The manufacturer specifies the maximum bandwidth of the interface: at what speed files will be recorded in reality, hundreds of factors affect the wear of the disk to the features of the files.
Therefore, to obtain real data, the maximum speed indicator needs to be divided by 3-5. That is, on high-speed SATA 3, the film will be downloaded not 10 seconds, and about a minute. SATA 1 should count for a few minutes.
New devices are produced mainly on the basis of SATA 3.
PCI-E. - This interface is used mainly to connect solid-state disks - SSD. On the PCI-E database, several connectors were created, for example m2.
USB - This interface is used to connect external disks. Here are the popular versions.
- USB 2 is a pretty slow but common format for HDD and flash drive. Maximum speed - up to 60 megabytes per second. In reality, such HDDs write orders 1-10 megabytes per second, that is, the film weighing 8 GB will download about 10 minutes.
- USB 3.0 is a modern standard with high speed, bandwidth up to 4.8 gigabit per second. If you look at the tests, the hard disk via USB 3.0 can record at speeds. 1-15 megabytes. per second. Cinema is downloaded 1-3 minutes.
- USB 3.2 Type C is a USB specification with even greater speed. Blowing capacity up to 10 gigabit, in reality, such a disk can produce up to several dozen megabytes per second. Cinema will turn out to record literally per minute.
Suitable interfaces should be not only in the hard disk, but also in the device itself to which you will connect the disk. Therefore, before purchasing an internal hard disk, check for the presence of the necessary interfaces on the motherboard. This can be done in the free Hwinfo program in the Motherboard section.
If you buy an external disk, consider backward compatibility: you can use the USB 3.0 disc in the old USB connector 2, only the speed will be minimal. Therefore, to buy an expensive external SSD for an ordinary laptop there is no point.
For example: 💾 HDD on SATA 2 - TOSHIBA for 3090 Р💾 HDD on SATA 3 - Western for 4144 Р💾 SSD on PCI-E, M2 - WD Black for 7399 Р💾 HDD on USB 3.0 - Seagate for 4190 Р
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Data transfer rate
Although some manufacturers indicate the data transfer rate, this is in any case the relative, conditional indicator. Dozens of parameters affect the reading and writing speed - from the internal sort of rotation speed and the design features to external: connection interfaces, other devices, motherboard and other things.
If you plan to buy an HDD, you can focus on the speed of rotation of the spindle - this is the axis that turns the same plates:
- 5,400 revolutions per minute - slower, less noise, less heat dissipation, and therefore reliable;
- 7,200 revolutions per minute - faster, more noise, slightly less reliability.
It is better to focus on different characteristics depending on the needs.
If you need an internal hard drive For the operating system - choose SSD or HDD at 7200 rpm. So the computer will boot and work faster.
For data warehouse Suitable HDD for 5400 rpm. It works quietly, reliably.
As an external hard disk Convenient HDD with USB 3.0 interface. Such an interface will be with most laptops, computers and even TVs.
For example: 💾 SSD 500 GB - Samsung for 5299 Р💾 HDD on 4 TB - Western for 8714 Р💾 External HDD for 2 TB - Seagate for 4190 Р
The HDD disks are mainly the amount of memory from 500 GB to 10 TB, SSD drives from 128 GB to 2 TB. How many exactly you need memory depends on the tasks, but there are several features:
- The cost of HDD with a volume of up to 2 TB will be almost the same: it makes no sense to save and buy a 500 GB disc, if you can buy 2 TB for the same amount.
- In disks with a memory capacity of 4 TB and above, the price tag grows proportionally: it is easier to buy five 2 TB discs than one disk for 10 TB.
For example: 💾 HDD 500 GB - Western for 4090 Р💾 HDD for 2 TB - Seagate for 4879 Р💾 SSD for 250 GB - Samsung for 3760 Р💾 SSD for 1 TB - Samsung for 10 494 Р
What to pay attention to when selecting a hard disk
- Decide what you need a hard drive: To quickly loaded the computer or to store the file collection.
- When you choose an internal hard disk, be sure to check for the desired connectors in the motherboard.
- If you need an external disk, do not overpay for the newcomer interfaces: all the same they will not work if your old USB 3.0 laptop is in your laptop.
- Memory is a lot - think if you really need a huge disk on 4 TB. Most likely, the rapid SSD 500 GB and 1 TB storage will be enough.
He is magnetic. It is electric. He is photon. No, this is not a new superhero trio from the Marvel Universe. We are talking about the storage of our precious digital data. We need to store them somewhere, reliably and stable so that we can have access to them and change the eye in the blink. Forget about the iron man and Torah - we are talking about hard drives!
So, let's plunge into the study of the anatomy of the devices that we today use for the storage of billions of data bits.
You Spin Me Right Round, Baby
Mechanical Hard disk drive (Hard Disk Drive, HDD) was a standard for storage systems for computers around the world for more than 30 years, but underlying technology is much older.
The first commercial HDD company IBM released in 1956
His capacity was as much as 3.75 MB. And in general, for all these years, the overall structure of the drive has not changed much. It still has discs that are used to store data magnetization, and there are devices for reading / writeing these data. Changed And very much, the amount of data that can be stored on them.
In 1987, it was possible to buy an HDD for 20 MB
about 350 dollars; today for the same money
You can buy 14 TB: in 700,000 Once larger volume.
We will look at the device not quite such a size, but also worthy of modern standards: 3.5-inch HDD Seagate Barracuda 3 TB, in particular, model ST3000DM001
not known for its high percentage of failures
and caused by these legal processes
. The drive we studied is already dead, so it will be more like an autopsy than an anatomy lesson.
The main mass of the hard disk is cast metal. Forces inside the device with active use can be quite serious, so the thick metal prevents bending and vibrations of the case. Even in the tiny 1.8-inch HDDs, metal is used as a material of the housing, but they are usually not done from steel, but from aluminum, because they should be as easy as possible.
Turning the drive, we see a printed circuit board and several connectors. The connector at the top of the board is used for the motor rotating wheels, and the bottom three (left to right) is the contacts under the jumpers that allow you to configure the drive to certain configurations, the SATA data connector (Serial ATA) and the SATA power connector.
Serial ATA first appeared in 2000. In desktop computers, this is the standard system used to connect the drives to the rest of the computer. The format specification has undergone many revisions, and now we use the version 3.4. Our hard disk corpse has a more old version, but the difference is only one contact in the power connector.
Differentiated signal is used in data transfers for receiving and receiving data.
: Contacts A + and A- are used for Shows instructions and data into a hard disk, and contacts B - for receipt These signals. Similar use of paired conductors significantly reduces the effect on the signal of electrical noise, that is, the device can work faster.
If we talk about food, then we see that the connector has a pair of contacts of each voltage (+3.3, +5 and + 12V); However, most of them are not used, because HDD does not require a lot of nutrition. This particular Seagate model at an active load uses less than 10 W. Contacts marked as PC are used for Precharge. : This feature allows you to pull out and connect a hard disk while the computer continues to work (this is called hot swapping ).
Contact with the PWDIS label allows you to remotely restart (Remote Reset)
Hard disk, but this feature is supported only from the SATA 3.3 version, so in my disk it is just another power line + 3.3V. And the last contact, marked like SSU, simply reports to a computer, whether the hard disk supports the spindle promotion technology Staggered Spin Up. .
Before the computer can use them, discs inside the device (which we will soon see), must unlock until full speed. But if a lot of hard drives are installed in the machine, then a sudden simultaneous power query can harm the system. The gradual spindle promotion completely eliminates the possibility of such problems, but at the same time, before obtaining full access to the HDD, you will have to wait a few seconds.
After removing the circuit board, you can see how it connects with the components inside the device. HDD. not sealed With the exception of devices with very large capacities - helium is used in them instead of air, because it is much less dense and creates fewer problems in drives with a large number of disks. On the other hand, it is not worth exposing the usual drives to the open exposure to the environment.
Through the use of such connections, the number of input points is minimized through which dirt and dust can enter inside the drive; In the metal case there is a hole (a large white point in the lower left corner of the image), which allows to maintain inside the pressure of the environment.
Now, when the printed circuit board is removed, let's see what is inside. There are four main chips:
- LSI B64002: The main controller chip, machining instructions, transmitting data streams inside and outward, corrective errors, etc.
- Samsung K4T51163QJ: 64 MB DDR2 SDRAM with a clock frequency of 800 MHz used to caching data
- Smooth McKXL: Manages the engine torque drives
- WinBond 25Q40BWS05: 500 KB sequential flash memory used to store the built-in drive (a bit similar to the computer BIOS)
PCB components of various HDDs may differ. For large volumes, more cache is required (in the most modern monsters there can be up to 256 MB DDR3), and the chip of the main controller can be slightly more sophisticated in the processing of errors, but in general the differences are not so high.
Open the drive simply, it is enough to unscrew several TORX bolts and voila! We inside ...
Considering that it occupies the main part of the device, our attention immediately attracts a large metal circle; It is easy to understand why drives are called disk . Correct them correctly Plates ; They are made of glass or aluminum and are covered with several layers of various materials. This 3 TB drive has three plates, that is, 500 GB should be stored on each side of one plate.
The image is pretty dusty, such dirty plates do not correspond to the design and production accuracy necessary for their manufacture. In our example, the HDD itself aluminum disk has a thickness of 0.04 inches (1 mm), but polished to such an extent that the average height of the deviations on the surface is less than 0.000001 inches (approximately 30 nm).
The base layer has a depth of only 0.0004 inches (10 microns) and consists of several layers of materials applied to the metal. Application is performed using chemical nickel
followed by vacuum spraying
prepare disk for the main magnetic materials used to store digital data.
This material is usually a complex cobalt alloy and composed of concentric circles, each of which is about 0.00001 inches (approximately 250 nm) in width and 0.000001 inches (25 nm) in depth. On the micro level of metal alloys form the grain, similar to soap bubbles on the surface of the water.
Each grain has its own magnetic field, but it can be converted in a given direction. Grouping such fields leads to data bits (0 and 1). If you want to learn more about this topic, then read this document.
University of Yale. The latter coatings are carbon layer for protection, and then a polymer to reduce contact friction. Together, their thickness is not more than 0.0000005 inches (12 nm).
Soon we will see why the plates should be made with such strict tolerances, but still surprisingly realize that only $ 15
You can become a proud owner of a device manufactured with nanometer accuracy!
However, let's return to the HDD itself and see what else is in it.
The yellow cover is shown in yellow, reliably fastening the plate to Spindle drive electric motor - electric drive rotating discs. In this HDD, they rotate with a frequency of 7200 RPM (revolutions / min), but in other models they can work slower. Slow drives have reduced noise and energy consumption, but also less, and faster drives can reach 15,000 RPM speeds.
To reduce damage applied to dust and air moisture, used Recycling filter (Green Square), collecting small particles and holding them inside. The air moved by rotation of the plates provides a constant flow through the filter. Above the disks and next to the filter there is one of three Plate dividers : Help reduce vibrations and maintain as an uniform air flow as possible.
In the left side of the image in a blue square, one of two permanent sodes magnets is specified. They provide a magnetic field needed to move the component specified in red. Let's separate these details to see them better.
What looks like a white plaster is another filter, only he cleans particles and gases, falling outside through the hole, which we have seen above. Metal spikes are Levers moving heads on which are located read-write heads Hard disk. They are moving along the surface of the plates (top and bottom) at a huge speed.
Look at this video created by The Slow Mo Guys
To see how fast they are:
In the design, something like a step electric motor
; To move the levers along the solenoid at the base of the levers, an electric current is performed.
Summarized them Sound coils Because they use the same principle that is used in the speakers and microphones to move the membranes. The current generates a magnetic field around them, which reacts to the field created by rod permanent magnets.
Do not forget that data tracks tiny , Therefore, the positioning of the levers must be extremely accurate as everything else in the drive. Some hard drives have multistage levers that make small changes in the direction of only one part of the whole lever.
In some hard drives, the data tracks are superimposed on each other. This technology is called Tiled magnetic record (Shingled Magnetic Recording), and its requirements for accuracy and positioning (that is, to getting constantly at one point) is still steady.
At the very end of the levers there are very sensitive read-write heads. Our HDD contains 3 plates and 6 heads, and each of them swims Over the disk during its rotation. For this head are suspended on ultrathine metal strips.
And here we can see why our anatomical sample died - at least one of the heads died, and whatever caused initial damage, it also walked one of the levers. The entire component of the head is so small that, as seen below, it is very difficult to get its high-quality snapshot with a regular camera.
However, we can disassemble individual parts. Gray block is a specially manufactured item called "Slider" : When the disk rotates under it, the air flow creates lifting force by lifting the head from the surface. And when we say "raises", we mean a gap of a width of only 0.0000002 inches or less than 5 nm.
A little further, and the heads will not be able to recognize changes in magnetic pathways; If the heads lay on the surface, they would simply scratch the coating. That is why it is necessary to filter the air inside the hull of the drive: dust and moisture on the surface of the disk just break the heads.
Tiny metal "SEST" at the end of the head helps with overall aerodynamics. However, to see parts that read and write, we need a better photo.
In this image of another hard disk, the reader and recorder is located under all electrical connections. Recording is performed by the system Tonclosure inductance (Thin Film Induction, TFI), and reading - Tunnel Magointezistive device (Tunneling MagnetoreSistive Device, TMR).
The TMR signals created are very weak and before shipping must pass through the amplifier to increase levels. The chip responsible for this is near the base of the levers in the image below.
As stated in the introduction of the article, the mechanical components and the principle of operation of the hard disk were almost not changed over many years. Most of the magnetic pathways and read-write heads, creating increasingly narrow and dense tracks, which ultimately led to an increase in the volume of stored information.
However, mechanical hard drives have obvious speed limitations. It takes time to move the levers to the desired position, and if the data is scattered along different paths on different plates, then the drive will spend quite a few microseconds in search of bits.
Before switching to another type of drives, let's point out the estimated speed indicators of a typical HDD. We used CrystaldiskMark benchmark
To estimate the hard disk WD 3.5 "5400 RPM 2 TB
In the first two lines, the amount of MB per second is specified when executing the serial (long, continuous list) and random (transitions throughout the drive) reading and writing. The following line shows the IOPS value, that is, the number of I / O operations performed every second. The last line shows the average delay (time in microseconds) between the transmission of the read or write operation and receiving data values.
In general, we strive to ensure that the values in the first three lines are as much as possible, and in the last line - as little as possible. Do not worry about the numbers themselves, we simply use them for comparison when we consider another type of drive: a solid-state drive.