Computer hard disk diagram. How the hard disk is arranged (HDD). Magnetic principle of reading and writing information

Hard disk consists of two main parts: the humbling and controller.

Figure 1 - Block - Scheme hard disk

Figure 2 - Basic hard disk design elements

1.2. Hard disk device

The entire hard drive, as a device, is divided, as we noted, into two major components: the electronics and the Hermon Plat or the "Bank", inside which magnetic discs are already located, the magnetic head unit, the spindle engine.

Figure 3- Appearance Maxtor hard disk

1.3. Electronics Fee (Controller)

Electronics board or hard disk controller, in fact, a small computer.

Figure 4 - Appearance of electronics fees (controller) of the hard disk of the company MAXTOR

On the board, modern hard drives can be found a processor, memory (RAM), ROM. The processor is processed by the processing of data received from the data heads and the transformation of them to understandable Computer "Language" - ATA standard. He does it, like a computer in RAM RAM. ROM is needed to start as BIOS on motherboard. What is engaged in the engine control chip is understandable of its name. When you turn on the controller card reads the service information and if it is correct, then hDD Starting work. But what to do if the electronics board fails and, as a result, there is no access to documents, photographs, etc., because the hard disk broke?

Of course, a desire to change this ill-fated fee to the "donor" are similar from the hard disk, because they are so similar, and consider their information. But not everything is so simple, as it seems at first glance. As it is known, progress does not stand still, and manufacturers of hard drives constantly improve their products, make changes to the technology of manufacturing hard drives and, as a result, new ranges of hard drive models appear, which differ in the record density, firmware, the design of individual nodes, the circuitry of the electronics board. It is for this reason on most hard disks Controllers have thin settings and non-interchangeable.

Consequently, the conclusion: not possessing complete information On the interchangeability of controllers on hard drives, unqualified independent attempts to restore data in the event of replacement of electronics cards can not only aggravate the cause of the breakage, but also significantly reduce the chances of successful recovery of information from the NJD.

Footnote:

Hard drive controllers

Figure 5 - Controller

The actual drive controller is physically located on the electronics board and is designed to provide transformation operations and forwarding information from read / write heads to the drive interface. Often, the controller is called the drive interface or the PC interface with the drive, which, in general, is not true.

The hard drive controller is the most complex device - a microcomputer, with its processor, RAM and ROM, schemes and an input / output system, etc. However, in most cases, manufacturers are placed in one or two microchips.

The controller is engaged in a variety of data flow conversion operations. Since the length of the tracks is unequal, the data on various paths must be recorded unevenly. It becomes a problem, compared with flexible discs, for carriers with high density Entries (number of tracks more than 1000). Simple controllers, as a rule, write down the same amount of information on each track, regardless of its length. To do this, the controller packs the data is more tight, starting with a particular track. The cylinder (in the case of a larger than one disk, all the tracks that are one under the other are called a cylinder), from which a more dense packaging of data begins, is called the initial precompensation cylinder (Starting Cylinder for Precompensation - SCP). To compensate for the distortion of information when reading, recording data is made with a preliminary displacement of bits, which takes into account distortion.

In the article we will talk about the hard disk device, namely, we will analyze what is the hard disk controller, we'll see the photo and tell about its main components, as well as study the terminology in Russian and in English.

An example for us will be the disk Western Digital. Model WD2000JS-00MHB0 and an older model Seagate Baracuda 7200.10 ST3250620A

Type of hard disk from below

Control fee or electronics fee, in the commoner it is like to call the controller, and in English it is indicated by Printed Circuit Board (PCB). We see the power connector, SATA or IDE connector, the board itself from the textolite, on it contacts and copper tracks. The fee is attached to several screws to the disk housing, its main functionality is to control the work of the hard drive. The disk housing is an aluminum box sometimes its name "bank", more official name of the Heroble (HDA, Head and disk. Assembly), the name "Heroble" is used to designate the housing along with the contents of the disk

By reloading a few bolts, we remove the board. Consider in more detail what components are located on it from the reverse side.

Seagate electronics board

The center is the microcontroller, it is called the MCU processor, it is decrypted as Micro Controller Unit. The main parts of the microcontroller:

1) CPU CPU, producing all calculations (Central Processor Unit);

2) read-write channel (READ-WRITE CHANNEL). A device that converts analog signal into digital data that is running with BMG (magnetic head unit) when reading and reverse operation when recording.

The processor has an input and output ports (IO Ports), they are used to control other components on the electronics board and data transmission via the interface (SATA, IDE, SAS)

WD electronics board

Memory chip Hemory chip Determines the size of the hard drive cache, the usual is used dDR memory SDRAM. The memory is divided into the memory of the firmware and the cache itself (buffer memory). The central processor, when you turn on the disk, first loads the micro firmware (modules).

VCM (Voice Coil Motor) Controller is an engine control controller, BMG, a power source for the processor. It is designed for work even at a temperature of C. achieving 100 degrees.

The first part of the disk is stored in flash memory when power is supplied, the disk microcontroller loads the contents of the flash memory and starts the code execution. If the code load is incorrectly load or malfunction, the disc will not be promoted. Flash memory chip is embedded in the controller, while a separate element on the electronics card you will not find it.

Most frequent cause HDD breakdowns is the failure of the electronics board.

Diving of boards can be divided into 2 types: electromechanical and logical. Electromechanical breakdows mainly include the burnout of the protective elements in the power circuit. This happens because of the so-called tristor Effect BP - when you turn on \\ power off, the upper and lower keys are unlocked, and occurs sharp rise of current consumption, which leads to a "trial" of the protective elements of the hard disk. Such elements are either in a short circuit, or go "into the break."

Symptoms are manifested as follows:

• When you turn on the computer with a "burnt" HDD connected to it, the computer does not turn on, or at all without reacting to pressing the power button
• The computer when turned on briefly turns on and off immediately. The same is true and when connected to such a disk, a separate power connector from external BP
• When power is applied to the hard disk, the hard drive does not submit signs of operation: the spindle engine does not rotate, no noise, squeaks, etc. are not heard.

Find a fault is not difficult, even if you have seen first this type Boards - they are all arranged similarly and TVS diodes, like protective SMD fuses, will be located close to the power connector. Using a multimeter, check these elements and detect faulty.

TVs-protective diodes: when the impulse appears, the anode and cathode and the dark side of the force are sintered on them.

To replace TVS-protective diodes, it is better to use a deliberately feeble fee from the donor board. For example, we take any fee from Seagate 3.5 7200.7-12, WD 3.5 "(any SATA) or SAMSUNG 3.5" SATA \\ IDE and find in the desired chain (+5 or +12 V) externally similar, and dropping his.

But in the actually the hard drive will earn and without these elements. We drag out, thereby removing the short circuit and everything, the disk works. However, it is not recommended to do this, especially if you want to save the information on the HDD and do not want to completely burn the drive. Without protection at the entrance, the Winchester will receive serious damage and a simple substitution of 1-2 elements here can no longer do.

After replacing the desired items instead of burnt, before installing the board on the handle and connect the power, it is recommended to check the power circuit "+5 - Earth" and "+12 - Earth", and carefully examine the other parts on the HDD card on the subject of mature. Otherwise, there is a chance to burn freshly parked parts when turned on, and how maximum is a processor or switch in Herzone.

We check not only protective diodes near the power connector (at the top), but also the other elements

PriMER fee from HDD Samsung, where the user decided to independently eliminate the breakdown, saving the jumper, and burned the processor on the PCB.

If you can run the drive without diodes without diodes, then without SMD fuses, the disk will not work. The replacement can be found on another board, and WD is excellent for these purposes. This type of protection is often found on 2,5 "laptop drives:

Somehow a long time ago came across a chart of a stepper engine driver on the LB11880 chip, but since I had no such chip, and the engines were lying down a few pieces, I postponed an interesting project with the launch of the motor in a long box. Time passed, and now, with the development of China, there are no problems with the details, so I ordered MS, and I decided to collect and test the connection of high-speed motors from HDD. The driver diagram is taken standard:

Motor driver diagram

Next, there is an abbreviated description of the article, read full. The engine rotating the hard disk spindle (or CD / DVD-ROM) is the usual simultaneous three-phase motor direct current. The industry produces ready-made single-chip control drivers, which are also not required by the sensors of the rotor position, because the engine windings are actuated in the role of such sensors. Control microcircuits of tri-phase DC motors that do not require additional sensors are TDA5140; TDA5141; TDA5142; TDA5144; TDA5145 and of course LB11880..

The engine connected according to the specified schemes will accelerate until the limit of the generation frequency of the VCO chip, which is determined by the capacitor rates connected to the output 27 (than its capacity is less, the higher the frequency), or the engine will not be destroyed mechanically. It should not be too reduced by the capacitance of the condenser connected to the output 27, as it may make it difficult to start the engine. Adjusting the speed of rotation is made by changing the voltage at the output of 2 chips, respectively: VPIT - the maximum speed; 0 - The engine is stopped. From the author there is a seizure, but I spread my own option as more compact.

Later, the LB11880 chips ordered by me, sealed in two finished handkers and spent one of them. Everything works perfectly: the rate is regulated by the change, the turnover is difficult to determine, but I think it is up to 10,000 exactly, since the engine is buzzing decently.

In general, the beginning is put, I will think where to apply. There is a thought to make the same sharpening disk as the author. And now it was tested on a piece of plastic, made the type of fan, blowing just brutally at least in the photo is not even visible as it is spinning.

Raise the revolutions above 20,000 by switching the capacitors of the C10 condenser and the supply of MS to 18 V (18.5 per limit). On this voltage, I have a motor whistle overha! Here is a video with 12 volt food:

HDD Motor Video Connections

I connected the engine from the CD, drivened the 18 V diet, because in my ball inside the ball, accelerates so that it jumps everything around! It is a pity not to track the revolutions, but if you judge the sound, it is very big, to a thin whistle. Where to use such speeds, here is the question? Comes to mind mini Bulgarian, a board drill, a grinding machine ... a lot of applications - Think yourself. Collect, test, share your impressions. On the Internet there are many reviews using engines data in interesting homemade structures. On the Internet, I saw the video, there are Coolibins with these Motor Motor Masters, Super Fans, Sharpeners, You can put it out where to apply such anger, the motor here accelerates over 27,000 revolutions. With you was Igoran.

Hard disks, or, as they are also called, Winchesters are one of the most important components. computer system. Everyone knows about it. But here is not every modern user, even in principle, guesses how the hard disk functions. The principle of work, in general, for the basic understanding is quite simple, but there are nuances here, which further will be discussed.

Questions of destination and classification of hard drives?

The question of destination, of course, rhetorical. Any user, even if initial level, immediately will answer that the hard drive (it is the hard disk, he is Hard Drive or HDD) will immediately answer that it serves to store information.

In general, it is true. Do not forget that on the hard disk except operating system and user files, there are boot sectors created by OS, thanks to which it starts, as well as some labels for which you can quickly find on the disk necessary information.

Modern models are quite diverse: ordinary HDD, external hard drives, high-speed solid-state sSD drivesAlthough they are attributed to their hard disks and is not accepted. Next, it is proposed to consider the device and the principle hard work disk, if not in full, then, at least, in such a time to understand the main terms and processes.

Note that there is a special classification modern HDD. According to some basic criteria, among which the following can be distinguished:

• information storage method;
• type of carrier;
• method for organizing access to information.

Why is the hard disk called Winchester?

Today, many users are thinking about why they are called hard drives relating to small arms. It would seem that may be common between these two devices?

The term himself appeared back in 1973, when the first HDD in the world appeared on the market, the design of which consisted of two separate compartments in one hermetic container. The capacity of each compartment was 30 MB, which is why the engineers gave the Code name "30-30", which was fully consonant with the brand of popular at that time the gun "30-30 Winchester". True, in the early 90s in America and Europe, this name practically came out of use, but still remains popular in the post-Soviet space.

Device and principle of hard disk operation

But we were distracted. The principle of hard disk operation briefly can be described as reading or record information processes. But how does this happen? In order to understand the principle of operation of the magnetic hard disk, first of all it is necessary to study how it is arranged.

The hard disk itself is a set of plates, the number of which can vary from four to nine, interconnected by the shaft (axis), called the spindle. Plates are located one above the other. Most often, the material for their manufacturer is the aluminum, brass, ceramics, glass, etc. The plates themselves have a special magnetic coating in the form of a material called platter, based on gamma-ferrite-oxide, chromium oxide, ferrite barium, etc. . Each such plate in thickness is about 2 mm.

Radial heads are responsible for recording and reading information (one on each plate), and both surfaces are used in the plates. Behind which it can be from 3600 to 7,200 rpm, and the movement of the heads correspond to two electrical engines.

At the same time, the main principle of the hard disk of the computer is that the information is recorded not where it fell, and in strictly defined locations, called sectors that are located on concentric paths or tracks. In order not to be confused, uniform rules apply. It means that the principles of the work of drives on hard drives, from the point of view of their logical structure, are universal. For example, the size of one sector adopted for a single standard around the world is 512 bytes. In turn, the sectors are divided into clusters, which are sequences near the sectors located. And the features of the principle of the hard disk operation in this regard are that the exchange of information is just produced by entire clusters (an integer number of chains of sectors).

But how does the information reads? The principles of the drive on rigid magnetic discs look as follows: With the help of a special bracket, the reading head in a radial (spiralized) direction moves to the desired track and is positioned when the specified sector is turned over, and all the heads can move simultaneously, reading the same information not only from different tracks but also with different disks (plates). All tracks with the same sequence numbers are called cylinders.

In this case, one other principle of the hard disk operation can be distinguished: the closer the reading head to the magnetic surface (but does not concern it), the higher the recording density.

How is the record and reading information?

Hard drives, or hard drives, therefore were called magnetic, that they use the laws of magnetism physics, formulated by the Faraday and Maxwell.

As already mentioned, a magnetic coating is applied to the plates from the non-magnetic sensitive material, the thickness of which is only a few micrometers. In the process of operation, a magnetic field arises, having a so-called domain structure.

The magnetic domain is a strictly limited border with the magnetized ferroallo region. Further, the principle of hard disk operation can be briefly described as follows: when the external magnetic field is exposed to the effect of the disk, it starts to focus strictly along the magnetic lines, and when exposure to the disks, the zones of residual magnetization appear, in which the information has previously been kept in the main field. .

For creating the external field, the reading head corresponds to the creation of the appearance, and when reading the residual magnetization zone, being opposite the head, creates an electromotive force or EMF. Further, everything is simple: the change in EMF corresponds to a unit in binary code, and its absence or termination is zero. EMF change time is customary called a bit element.

In addition, the magnetic surface is purely for considerations of informatics can be associated as a certain point sequence of bits of information. But since the location of such points is absolutely accurately calculated, it is necessary to install some predetermined labels on the disk, which helped determine the desired location. Creating such labels is called formatting (roughly speaking, disk breakdown on tracks and sectors combined into clusters).

Logical structure and principle of hard disk operation in terms of formatting

Concerning logical organization HDD, here in the first place it is formatting, which distinguishes two main types: low-level (physical) and high-level (logical). Without these stages, nothing to talk about the hard disk to speak. On how to initialize the new hard drive, will be said separately.

Low-level formatting presupposes physical impact On the HDD surface, which creates sectors located along the tracks. It is curious that the principle of the hard disk operation is such that each created sector has its own unique address that includes the sector itself, the number of the track on which it is located, and the number of the plate. Thus, when enterprise direct access is the same rAM Drawn directly at a given address, and does not look for the necessary information over the entire surface, due to which the speed is achieved (although this is not the most important thing). Please note that when performing low-level formatting, absolutely all information is erased, and it is not subject to restoration in most cases.

Another thing is logical formatting (in Windows-systems this fast formatting or Quick Format). In addition, these processes are also applicable to the creation of logical partitions, which are a certain area of \u200b\u200bthe main hard disk operating on the same principles.

Logical formatting, first of all, affects system regionwhich consists of the boot sector and partition tables (boot record Boot Record), file placement tables (FAT, NTFS, etc.) and root directory (root directory).

Recording information to sectors is performed through a cluster in several parts, and in one cluster there can be no two identical object (file). Actually, the creation of a logical partition, as if separating it from the main system partitionAs a result, the information on it is stored, when errors appear and fail or removal failures.

The main characteristics of HDD.

It seems that the principle of operation of the hard disk is slightly understood. We now turn to the main characteristics that give a complete view of all the possibilities (or disadvantages) of modern hard drives.

The principle of hard disk operation and main characteristics can be completely different. To understand what this is speech, We highlight the most basic parameters that are characterized by all the information-known information for today:

• capacity (volume);
• speed (data access speed, read and write information);
• interface (connection method, controller type).

The container is a total amount of information that can be recorded and saved on the hard drive. The HDD Production Industry is developing so quickly that today there are already hard drives with volumes of about 2 TB and higher. And, as it is believed, this is not the limit.

The interface is the most significant characteristic. It determines how exactly the device connects to the motherboard, which controller is used, how the IDE, SATA and SCSI are considered the main and most common interfaces.

Discs with IDE interface are distinguished by a low cost, however, among the main disadvantages, a limited number of simultaneously connected devices can be distinguished (maximum four) and low data transfer rate (even if you support direct access to Ultra DMA memory or Ultra ATA protocols (MODE 2 and MODE 4) Although, as it is believed, their application allows you to increase the speed of reading / write to the level of 16 MB / s, but in reality the speed is much lower. In addition, the installation of the UDMA mode is required special Driverwhich, in theory, should be supplied with motherboard.

Speaking about what is the principle of the hard disk and characteristics, it is impossible to bypass the party and which is the heir iDE version ATA. The advantage of this technology is that read / write speed can be enhanced up to 100 MB / s due to the use of high-speed Fireware IEEE-1394 tire.

Finally, the SCSI interface compared to the previous two is the most flexible and most speed (recording / reading speed reaches 160 MB / s and above). But there are two hard drives in almost two times more expensive. But the number of simultaneously connected storage devices of information is from seven to fifteen, the connection can be carried out without deisitious a computer, and the cable length can be about 15-30 meters. Actually, this type of HDD is mostly applied not in user PC, but on servers.

Speed \u200b\u200bcharacterizing the transfer rate and throughput I / O, usually expressed by the transmission time and the amount of data transmitted by sequentially and is expressed in MB / s.

Some additional parameters

Speaking about what is the principle of hard disk operation and which parameters affect its operation, you can not get around the parties and some additional characteristicsFrom which speed may depend on or even the life of the device.

Here in the first place is the speed of rotation, which directly affects the time of search and initialization (recognition) of the desired sector. This is the so-called hidden search time - the interval during which the necessary sector turns to the reading head. Today adopted several standards for the speed of spindle rotation, expressed in revolutions per minute with the time of delay in milliseconds:

• 3600 - 8,33;
• 4500 - 6,67;
• 5400 - 5,56;
• 7200 - 4,17.

It is easy to notice that the higher the speed, the smaller the time is spent on the sector search, and in the physical plan - to the turnover of the disc before installing the desired positioning point of the plate.

Another parameter is the internal transfer rate. It is minimal on the external tracks, but increases with a gradual transition to the inner tracks. Thus, the same defragmentation process, which is the movement of frequently used data into the fastest area of \u200b\u200bthe disk, is nothing but to transfer them to the inner track with a greater read speed. Exterior speed It has fixed values \u200b\u200band directly depends on the interface used.

Finally, one of important moments associated with the presence of its own cache or buffer from the hard disk. In fact, the principle of hard disk in terms of using buffer is similar to the operational or virtual memory. The greater the amount of cache memory (128-256 KB), the faster the hard disk will work.

Main HDD Requirements

The basic requirements that in most cases are presented to hard disks, not so much. The main thing is a long service life and reliability.

The main standard for most HDD is the service life of about 5-7 years with the time of operation of at least five hundred thousand hours, but for high-end hard drives this indicator is at least a million hours.

As for reliability, the S.A.A.R.R.T Self-test function is responsible for this, which monitors the state of individual elements of the hard disk, performing constant monitoring. On the basis of the data collected, even a certain forecast for the emergence of possible malfunctions may be formed.

It goes without saying that the user should not remain aside. So, for example, when working with HDD is extremely important to observe the optimal temperature regime (0-50 ± 10 degrees Celsius), avoid shake, shocks and drops of the hard drive, falling into it dust or other small particles, etc. By the way, many will be It is interesting to know that the same particles of tobacco smoke are about twice the distance between the reading head and the magnetic surface of the hard drive, and the human hair is 5-10 times.

Initialization issues in the system when replacing Winchester

Now a few words about what actions need to be taken if for some reason the user has changed the hard disk or installed the valve.

Fully describe this process will not, but we will dwell only at the main stages. First, the hard drive must be connected and see in bIOS settingswhether new equipment was determined in the Disk Administration section to initialize and create boot record, Create a simple Tom, assign it to the identifier (Literature) and formatting with a selection file System. Only after that the new "screw" will be fully ready for work.

Conclusion

Here, in fact, all that briefly concerns the foundations of the functioning and characteristics of modern hard drives. Principle of operation outdoor hard The disk was not considered in principle, since it is practically no different from what is used for stationary HDD. The only difference consists only in the connection method additional drive to a computer or laptop. The most common is to connect via a USB interface that is directly connected to the motherboard. At the same time, if you want to ensure maximum speed, it is better to use uSB standard 3.0 (port inside is painted in blue), of course, provided that outdoor HDD It supports.

Otherwise, it seems, to many at least a little more clearly, as the hard disk is functioning. Perhaps, too much, too much, especially even from the school course of physics, nevertheless, without this, to fully understand all the basic principles and methods laid down in the technologies of production and the use of HDD, will not understand.