Physical and logical structure of student hard disk gr. Hard disk is the logical structure of the hard drive

The initial sector of the disk has a master root record that is loaded into memory and executed. The last part of this sector has a partition table - a 4 element table with 16 byte elements. This table is managed by the FDISK program. When booting, the ROM-BIOS loads this sector with an entry about the table. This is done in order to determine the active partition. Then the correct root sector is read into memory and executed.
Table 1 - The structure of the master root record and the partition table

Table 2 - Structure of the section descriptor

The partition code is intended to identify and position the extended and main partitions on the disk. Once a partition is found, its size and coordinates can be read from certain fields. If in the section code field 0 , then the descriptor can be considered empty, and it will be certain that there is no partition on the disk.
Table 3 - Partition codes for Microsoft OS

The following codes are reserved for the OS of other companies:

• 02h - section СР / М
• 03h - Xenis section
• 07h - OS / 2 partition (HPFS)

Cylinder and sector numbers are 10 and 6 bits:

They are packed so that when the CX is loaded with a 16-bit value, it is ready to invoke INT 13h to read a specific portion of the disk. After reading the master boot record into the memory area sect_buf function:

CMP byte ptr sect_buf, 80h

will check if the first section is active. And the following algorithm will load CX to call INT 13h to read the root sector of partition # 1.

MOV CX, sect_buf

Options relative sector at offset 08h in each section it is equal to the head, sector and cylinder of the starting address of the section. The relative sector number increases first for each sector on the head, then for each head, and finally for each cylinder. Formula:

rel_sec = (# Cyl * sec_on_cyl * heads) + (#Goal * sec_n_cyl) + (# Sec -1)

Sections start at an even cylinder number, except for the first section.

Root sector structure

Floppy or partition root sector format hard disk shown in Fig. 1.

Picture 1

Hard disk parameter table

This 16-byte structure is located at the address of the INT 41h interrupt vector (4-byte address at 0: 0104). The characteristics for the second hard disk (if it exists) are located at the address of the vector INT 46h.
Table 5 - Format of the hard disk table

File Allocation Table (FAT)

The file size can change over time. If we assume that the file is stored only in contiguous sectors, then when the file size increases, the OS must completely rewrite it to another location on the disk. To simplify the task, in modern operating systems, file allocation tables (FAT) are implemented, which allow you to store a file in several separate sections.

In FAT, the data area of ​​a logical disk is divided into sections of the same size - ... The number of sectors in a cluster is a multiple of 2 N and can take values ​​from 1 to 64. In the file directory, for each file, there is an initial element number in the FAT table, equal to the first cluster in the file chain. An example is shown in Figure 2. The figure shows:

• MYFILE.TXT occupies 10 clusters. The first cluster is 08, and the last 1Bh. A chain of clusters - 08h, 09h, 0Ah, 0Bh, 15h, 16h, 17h, 19h, 1Ah, 1Bh. Each component in the chain points to the next component in the chain, as shown in Table 6.
• Cluster 18h is marked as defective and is not part of the chain
• Clusters 06h, 07h, 0Ch-14h and 1Ch-1Fh are empty and available for other chains

Table 6 - Meaning of FAT elements

FAT starts with logical sector 1 in the DOS partition. In principle, you need to read the root sector DX = 0, and take the offset 0Eh. There we already find out the number of root and reserve sectors that stand in front of the FAT. To read any FAT component along the chain, you need to read the entire FAT and get the starting cluster number from the table of contents, and in the case of FAT12:

• multiply the cluster number by 3
• divide result by 2
• read a 16-bit word from FAT using the result of the previous round as the address
• If the element number is even, but you need to AND over the word and mask 0FFFh. If it is odd, then shift the value to the right by 4 bits.

The topic of GPT and MBR disk partition tables became relevant after the distribution of computers and laptops with preinstalled Windows 10 and 8. In this manual, there are two ways to find out which partition table, GPT or MBR a disk (HDD or SSD) has - by means of the operating system, and at Windows installation to the computer (i.e. without loading the OS). All methods can be used in Windows 10, 8 and Windows 7.

You may also find useful materials related to converting a disk from one partition table to another and solving typical problems caused by a partition table that is not supported under the current configuration: (and vice versa), about errors during Windows installation:,.

To use this method, you can either in Windows, or press Shift + F10 (on some laptops Shift + Fn + F10) during the installation of Windows from a disk or flash drive to open the command prompt.

V command line in order, enter the commands:

• diskpart
• list disk
• exit

Notice the last column in the output of the list disk command. If there is a mark (asterisk) there, then this disk has a GPT partition style, those disks that do not have such a mark are MBR (usually MBR, since there may be other options, for example, the system cannot determine what kind of disk it is ).

How to find out MBR or GPT disk in Windows PowerShell

Another way is to use Windows PowerShell and the command to get information about drives: (from the Administrator or not - it doesn't matter) and enter the command:

Get-Disk | ft -Auto

As a result, in the table you will receive information about the disks of your computer or laptop, including the partition structure in the last column:

Indirect signs for determining the structure of partitions on disks

Well, there are some additional, not giving guarantees, but useful as additional information signs that allow you to find out if a GPT or MBR disk is used on your computer or laptop.

A hard disk drive (HDD) \ HDD (Hard Disk Drive) \ hard drive (media) is a material object capable of storing information.

Information storages can be classified according to the following criteria:

• information storage method: magnetoelectric, optical, magneto-optical;
• type of information carrier: drives on floppy and hard magnetic disks, optical and magneto-optical disks, magnetic tape, solid-state memory elements;
• the way of organizing access to information - drives of direct, sequential and block access;
• storage device type - embedded (internal), external, stand-alone, mobile (wearable), etc.

A significant part of the information storage devices currently in use are based on magnetic media.

Hard disk device

Winchester contains a set of plates, which are most often metal discs covered with a magnetic material - platter (gamma ferrite oxide, barium ferrite, chromium oxide ...) and connected by a spindle (shaft, axle).
The disks themselves (approximately 2mm thick) are made of aluminum, brass, ceramics or glass. (see pic)

Both surfaces of the discs are used for recording. Used 4-9 plates... The shaft rotates at a high constant speed (3600-7200 rpm.)
Rotation of discs and radical movement of heads is carried out using 2 electric motors.
Data is written or read using read / write heads one for each surface of the disc. The number of heads is equal to the number of working surfaces of all discs.

Information is recorded on the disk in strictly defined places - concentric tracks (tracks) ... The tracks are divided into sector. One sector contains 512 bytes of information.

The exchange of data between RAM and LMD is carried out sequentially with an integer (cluster). Cluster- chains of consecutive sectors (1,2,3,4, ...)

Special engine using the bracket, positions the read / write head over the specified track (moves it radially).
When the disc is turned, the head is positioned over the desired sector. Obviously, all heads move simultaneously and read information heads move simultaneously and read information from the same tracks of different information from the same tracks of different discs.

The tracks of the hard drive with the same serial number on different hard drives are called cylinder .
The read / write heads move in along the surface of the platter. The closer the head is to the surface of the disc without touching it, the higher the permissible recording density.

Winchester device

Magnetic principle of reading and writing information

magnetic principle of information recording

The physical foundations of the processes of recording and reproducing information on magnetic media were laid in the works of physicists M. Faraday (1791 - 1867) and D.K. Maxwell (1831 - 1879).

In magnetic storage media, digital recording is made on a magnetically sensitive material. Such materials include some types of iron oxides, nickel, cobalt and its compounds, alloys, as well as magnetoplastics and magnetoelasts with viscous plastics and rubber, micropowder magnetic materials.

The magnetic coating is several micrometers thick. The coating is applied to a non-magnetic substrate, which distinguishes between plastics for magnetic tapes and floppy disks, and aluminum alloys and composites for hard disks. The magnetic coating of the disk has a domain structure, i.e. consists of many tiny magnetized particles.

Magnetic domain (from Latin dominium - possession) is a microscopic, uniformly magnetized region in ferromagnetic samples, separated from neighboring regions by thin transition layers (domain boundaries).

Under the influence of an external magnetic field, the intrinsic magnetic fields domains are oriented in accordance with the direction of the magnetic field lines. After the cessation of the action of the external field, zones of remanent magnetization are formed on the surface of the domain. Thanks to this property, information on the effect of the magnetic field is stored on the magnetic medium.

When recording information, an external magnetic field is created using a magnetic head. In the process of reading the information of the remanent magnetization zone, being opposite to the magnetic head, electromotive force (EMF) is induced in it during reading.

The scheme for writing and reading from a magnetic disk is given in Fig. 3.1. The change in the direction of the EMF over a certain period of time is identified with a binary unit, and the absence of this change is identified with zero. The specified period of time is called bit element.

The surface of a magnetic medium is viewed as a series of dotted positions, each of which is associated with a bit of information. Because the location of these positions is imprecise, recording requires pre-printed markers to help locate the desired recording positions. To apply such synchronization marks, the disc must be divided into tracks.
and sectors - formatting.

Organization of quick access to information on disk is an important stage of data storage. Online access to any part of the disk surface is provided, firstly, by giving it a fast rotation and, secondly, by moving the magnetic read / write head along the radius of the disk.
The floppy disk spins at 300-360 rpm, while the hard disk spins at 3600-7200 rpm.

The logical device of the hard drive

The magnetic disk is initially not ready for use. To bring it into working condition, it must be formatted, i.e. the disk structure must be created.

The structure (layout) of the disk is created during the formatting process.

Formatting magnetic disks includes 2 stages:

1. physical formatting (low-level)
2. logical (high level).

Physical formatting breaks up the working surface of a disk into separate areas called sectors which are located along concentric circles - tracks.

In addition, sectors that are not suitable for data recording are determined, they are marked as bad in order to avoid using them. Each sector is the smallest unit of data on the disk and has its own address to provide direct access to it. The sector address includes the side number of the disc, the track number, and the sector number on the track. The physical parameters of the disk are set.

As a rule, the user does not need to deal with physical formatting, as in most cases hard drives come in formatted form. Generally speaking, this should be done by a specialized service center.

Low-level formatting must be done in the following cases:

• if a failure occurs in track 0, causing problems when booting from the hard disk, but the disk itself is available when booting from a floppy disk;
• if you are returning an old disk to working condition, for example, one that was moved from a broken computer.
• if the disk turned out to be formatted to work with another operating system;
• if the disk stopped working normally and all recovery methods did not give positive results.

Keep in mind that physical formatting is a very powerful operation- when it is executed, the data stored on the disk will be completely erased and it will be completely impossible to restore them! Therefore, do not start low-level formatting if you are not sure that you have saved all important data outside the hard drive!

After you perform low-level formatting, the next step follows - creating a partition of the hard disk into one or more logical drives - the best way deal with the confusion of directories and files scattered around the disk.

Without adding any hardware elements to your system, you get the opportunity to work with several parts of one hard disk as with several drives.
This does not increase the capacity of the disk, but you can significantly improve its organization. In addition, different logical drives can be used for different operating systems.

At logical formatting the final preparation of the medium for storing data takes place by the logical organization of disk space.
The disk is prepared for writing files to sectors created by low-level formatting.
After creating a partitioning table, the next stage follows - logical formatting of individual parts of the partition, hereinafter referred to as logical disks.

Logical disk - this is a certain area of ​​the hard disk that works in the same way as a separate drive.

Logical formatting is a much simpler process than low-level formatting.
In order to execute it, boot from the floppy disk containing the FORMAT utility.
If you have multiple logical drives, format them all sequentially.

During logical formatting, the disk is allocated system area, which consists of 3 parts:

• boot sector and partition table (Boot reсord)
• file allocation tables (FAT), in which the numbers of tracks and sectors that store files are recorded
• root directory (Root Direсtory).

Information is recorded in parts through the cluster. The same cluster cannot have 2 different files.
In addition, a name can be assigned to the disc at this stage.

HDD can be split into several logical drives and vice versa 2 hard drives can be combined into one logical one.

It is recommended to create at least two partitions on a hard disk (two logical disks): one of them is allocated for the operating system and software, the second disk is exclusively allocated for user data. Thus, the data and system files are stored separately from each other and in the event of an operating system failure, it is much more likely to save user data.

Characteristics of hard drives

Hard disks (hard drives) differ from each other in the following characteristics:

1. capacity
2. speed - the time of access to data, the speed of reading and writing information.
3. interface (connection method) - the type of controller to which the hard drive should be connected (most often IDE / EIDE and various SСSI variants).
4. other features

1. Capacity- the amount of information that fits on the disc (determined by the level of manufacturing technology).
Today the capacity is 500-2000 GB or more. Hard disk space is never too much.

2. Speed ​​of work (speed) disk is characterized by two indicators: disk access time and disk read / write speed.

Access time - the time required to move (position) the read / write heads to the desired track and the desired sector.
Average characteristic access time between two randomly selected tracks is about 8-12 ms (milliseconds), more fast disks have a time of 5-7ms.
The transition time to an adjacent track (adjacent cylinder) is less than 0.5 - 1.5ms. It also takes time to turn to the desired sector.
The total disk turnover time for today's hard drives is 8-16ms, the average sector latency is 3-8ms.
The shorter the access time, the faster the disk will run.

Read / write speed(I / O bandwidth) or data rate (transfer)- the transmission time of sequentially located data depends not only on the disk, but also on its controller, bus types, processor speed. The speed of slow disks is 1.5-3 Mb / s, for fast ones - 4-5 Mb / s, for the most recent ones - 20 Mb / s.
Winchesters with SCSI-interface support the rotation frequency of 10000 rpm. and the average seek time is 5ms, the data transfer rate is 40-80 Mb / s.

3.HDD connection interface standard - i.e. the type of controller to which the hard drive should be connected. It is located on the motherboard.
There are three main connection interfaces

1. IDE and its various variants

IDE (Integrated Disk Electronics) or (ATA) Advanced Technology Attachment
Advantages - simplicity and low cost

Transfer rates: 8.3, 16.7, 33.3, 66.6, 100 Mb / s. As the data evolves, the interface supports the expansion of the list of devices: hard disk, super-floppy, magneto-optics,
NML, CD-ROM, CD-R, DVD-ROM, LS-120, ZIP.

Some elements of parallelization (gneuing and disconnect / reconnect), data integrity control during transmission are introduced. The main drawback of IDE is a small number of connected devices (no more than 4), which is clearly not enough for a high-end PC.
Today IDE interfaces have switched to the new Ultra ATA exchange protocols. Significantly increasing your bandwidth
Mode 4 and DMA (Direct Memory Assess) Mode 2 allows data transfer at a speed of 16.6 Mb / s, but the actual data transfer rate would be much lower.
Ultra DMA / 33 and Ultra DMA / 66 standards, developed in February 98. by Quantum have 3 modes of operation 0,1,2 and 4, respectively, in the second mode, the carrier supports
transmission speed 33Mb / s. (Ultra DMA / 33 Mode 2) This high speed can only be achieved by exchanging with the drive's buffer. To take advantage of
Ultra DMA standards must meet 2 conditions:

1.Hardware support on the motherboard (chipset) and from the drive itself.

2. to maintain the Ultra DMA mode, like other DMA (direсt memory Assess-direct memory access).

Requires special driver for different chipsets. They are usually included in the kit motherboard, if necessary, it can be "downloaded"
from the Internet from the manufacturer's website motherboard.

The Ultra DMA standard is backward compatible with previous slower controllers.
Today's version: Ultra DMA / 100 (Late 2000) and Ultra DMA / 133 (2001).

SATA
Replacing IDE (ATA) with no other Fireware high-speed serial bus (IEEE-1394). The use of the new technology will allow to bring the transmission speed equal to 100Mb / s,
the reliability of the system is increased, this will allow installing devices without including a PC, which is absolutely impossible in the ATA interface.

SСSI (Small Сomputer System Interfaсe)- devices are 2 times more expensive than usual ones, they require a special controller on the motherboard.
Used for servers, publishing systems, CAD systems. Provide higher performance (speed up to 160Mb / s), a wide range of connected storage devices.
The SCSI controller must be purchased together with the corresponding disk.

SCSI advantage over IDE - flexibility and performance.
Flexibility lies in a large number of connected devices (7-15), and for IDE (4 maximum), a longer cable length.
Performance - high speed transmission and the ability to simultaneously process multiple transactions.

1. Ultra Sсsi 2/3 (Fast-20) up to 40Mb / s 16-bit version Ultra2 - SСSI standard up to 80Mb / s

2. Another SCSI-interface technology called Fiber Channel Arbitrated Loop (FC-AL) allows you to connect up to 100 Mbps, while the cable length is up to 30 meters. The FC-AL technology allows you to perform "hot" connection, ie. on the go, has additional lines for error control and correction (technology is more expensive than conventional SСSI).

4. Other features of modern hard drives

The huge variety of hard drive models makes it difficult to choose the right one.
In addition to the required capacity, performance is also very important, which is mainly determined by its physical characteristics.
These characteristics are the average seek time, rotation speed, internal and external transfer rate, and the size of the Cache memory.

4.1 Average search time.

The hard disk takes some time to move the magnetic head of the current position to a new one, required to read the next piece of information.
In each specific situation, this time is different, depending on the distance the head must move. Usually, only averaged values ​​are given in the specifications, and the averaging algorithms used by different companies are generally different, so that direct comparison is difficult.

For example, Fujitsu and Western Digital carry out all possible pairs of tracks, Maxtor and Quantum use the random access method. The result obtained can be additionally corrected.

The seek time value for writing is often slightly higher than for reading. Some manufacturers only give a lower value in their specifications (for reading). In any case, in addition to the average values, it is useful to take into account the maximum (through the entire disk),
and the minimum (that is, track to track) seek time.

4.2 Rotational speed

From the point of view of the speed of access to the desired fragment of the record, the rotation speed affects the value of the so-called latent time, which in order for the disk to turn to the magnetic head with the required sector.

The average value of this time corresponds to half a disk revolution and is 8.33 ms at 3600 rpm, 6.67 ms at 4500 rpm, 5.56 ms at 5400 rpm, 4.17 ms at 7200 rpm.

The latency value is comparable to the average seek time, so in some modes it can have the same, if not more, performance impact.

4.3 Internal baud rate

- the rate at which data is written to or read from disk. Due to the zone recording, it has a variable value - higher on the outer tracks and lower on the inner tracks.
When working with long files, in many cases it is this parameter that limits the transfer rate.

4.4 External baud rate

- rate (peak) with which data is transmitted through the interface.

It depends on the type of interface and most often has fixed values: 8.3; 11.1; 16.7Mb / s for Enhanced IDE (PIO Mode2, 3, 4); 33.3 66.6 100 for Ultra DMA; 5, 10, 20, 40, 80, 160 Mb / s for synchronous SСSI, Fast SСSI-2, FastWide SСSI-2 Ultra SСSI (16 bits), respectively.

4.5 Availability of the hard drive's own cache memory and its size (disk buffer).

The size and organization of the cache memory (internal buffer) can significantly affect the performance of the hard drive. As well as for regular Cache memory,
the performance gain slows down dramatically after reaching a certain volume.

Large Segmented Cache is useful for high-performance SСSI drives used in multitasking environments. The more cache, the faster the hard drive works (128-256Kb).

The impact of each of the parameters on the overall performance is difficult to isolate.

Hard drive requirements

The main requirement for the disks is that the reliability of operation is guaranteed by the long service life of the components of 5-7 years; good statistics, namely:

• mean time between failures not less than 500 thousand hours (top class 1 million hours or more.)
• built-in system of active monitoring of the state of disk nodes SMART / Self Monitoring Analysis and Report Technology.

Technology S.M.A.R.T. (Self-Monitoring Analysis and Reporting Technology) is an open industry standard developed at the time by Compaq, IBM and a number of other hard disk manufacturers.

The meaning of this technology lies in the internal self-diagnosis of the hard drive, which allows you to evaluate it Current state and inform about possible future problems that could lead to data loss or drive failure.

Constant monitoring of the state of all vital elements of the disc is carried out:
heads, working surfaces, an electric motor with a spindle, an electronics unit. For example, if signal attenuation is detected, then the information is overwritten and further observation occurs.
If the signal is again weakened, then the data is transferred to another location, and this cluster is placed as defective and inaccessible, and instead of it another cluster is available from the disk reserve.

When working with a hard disk, observe the temperature regime in which the drive is operating. Manufacturers guarantee the trouble-free operation of the hard drive at ambient temperatures in the range from 0C to 50C, although, in principle, without serious consequences, the boundaries can be changed by at least 10 degrees in both directions.
With large temperature deviations, an air gap of the required thickness may not form, which will lead to damage to the magnetic layer.

In general, HDD manufacturers pay quite a lot of attention to the reliability of their products.

The main problem is the ingress of foreign particles into the disk.

For comparison: a particle of tobacco smoke is twice the distance between the surface and the head, the thickness of a human hair is 5-10 times greater.
For the head, a meeting with such objects will result in a strong blow and, as a result, partial damage or complete failure.
Outwardly, this is noticeable as the appearance of a large number of regularly located unusable clusters.

Dangerous short-term large in modulus acceleration (overload) arising from impacts, falls, etc. For example, from a blow, the head sharply strikes a magnetic
layer and causes its destruction in the appropriate place. Or, conversely, it first moves in the opposite direction, and then, under the action of the elastic force, it is like a spring hitting the surface.
As a result, particles of a magnetic coating appear in the housing, which, again, can damage the head.

Do not think that under the action of centrifugal force they will fly away from the disk - the magnetic layer
will firmly attract them to itself. In principle, the consequences are not of the impact itself (you can somehow come to terms with the loss of a certain number of clusters), but the fact that particles are formed, which will certainly cause further damage to the disk.

To prevent such very unpleasant cases, various firms have resorted to all sorts of tricks. In addition to simply increasing the mechanical strength of the disk components, the intelligent S.M.A.R.T. technology is also used, which monitors the reliability of recording and data safety on the medium (see above).

Actually, the disk is always not formatted to its full capacity, there is some margin. This is mainly due to the fact that it is almost impossible to make a carrier,
on which absolutely the entire surface would be of high quality, there will certainly be bad clusters (bad). When a low-level disk is formatted, its electronics are configured as
so that it bypasses these bad areas, and for the user it was completely unnoticeable that the media has a defect. But if they are visible (for example, after formatting
the utility displays their number, other than zero), then this is already very bad.

If the warranty has not expired (and, in my opinion, it is best to buy an HDD with a warranty), then immediately take the disk to the seller and ask for a replacement media or a refund.
The seller, of course, will immediately begin to say that a couple of bad areas are not yet a cause for concern, but do not believe him. As already mentioned, this couple is likely to cause many more others, and subsequently a complete failure of the hard drive is generally possible.

The drive is especially sensitive to damage in working order, so you should not place the computer in a place where it can be exposed to various shocks, vibrations, and so on.

Preparing the hard drive for work

Let's start from the very beginning. Suppose you bought a hard disk drive and ribbon cable separately from your computer.
(The fact is that when buying assembled computer, you will receive a disc prepared for use).

A few words about handling him. A hard disk drive is a very complex product containing, in addition to electronics, precision mechanics.
Therefore, it requires careful handling - shocks, falls and strong vibrations can damage the mechanical part. As a rule, the drive board contains many small-sized elements and is not covered with sturdy covers. For this reason, you should take care of its safety.
The first thing to do after receiving a hard drive is to read the documentation that came with it - it will probably contain a lot of useful and interesting information... In this case, you should pay attention to the following points:

• the presence and options for installing jumpers that determine the configuration (installation) of the disk, for example, defining such a parameter as the physical name of the disk (they may be, but they may not be),
• the number of heads, cylinders, sectors on disks, the level of precompensation, and the type of disk. This information must be entered when prompted by the computer setup program.
  All this information will be needed when formatting the drive and preparing the machine for working with it.
• If the PC itself does not determine the parameters of your hard drive, installing a drive for which there is no documentation will become a bigger problem.
  Most hard drives contain labels with the manufacturer's name, device type (brand), and a table of invalid tracks.
  In addition, the drive can provide information about the number of heads, cylinders and sectors and the level of precompensation.

For the sake of fairness, it must be said that often only its title is written on a disc. But even in this case, you can find the required information either in the reference book,
or by calling the representative office of the company. At the same time, it is important to get answers to three questions:

• how should the jumpers be set in order to use the drive as master \ slave?
• how many cylinders, heads on the disk, how many sectors per track, what is the precompensation value?
• What type of disk is the best suited for this drive from the ROM BIOS?

With this information in hand, you can proceed to install the hard disk drive.

To install a hard drive in your computer, do the following:

1. Disable completely system unit from the power supply, remove the cover.
2. Connect the hard drive cable to the motherboard controller. If you install a second drive, you can use a flat cable from the first one if there is an additional connector on it, and you should remember that the speed of operation of different hard drives will be compared slowly to the side.
3. If necessary, change the jumpers according to the way of using the hard disk.
4. Install the drive to the free space and connect the ribbon cable from the controller on the board to the hard drive connector with a red stripe to the power supply, the power supply cable.
5. Securely fasten the hard drive with four screws on both sides, neatly / span the cables inside the computer so that when closing the cover you do not cut them,
6. Close the system unit.
7. If the PC itself did not detect the hard drive, then change the configuration of the computer using Setup so that the computer knows that a new device has been added to it.

Winchester manufacturers

Winchesters of the same capacity (but from different manufacturers) usually have more or less similar characteristics, and the differences are expressed mainly in the case design, form factor (in other words, dimensions) and duration warranty service... And the latter should be said especially: the cost of information on a modern hard drive often exceeds its own price many times.

If your disk has malfunctions, then trying to repair it - often means only exposing your data to additional risk.
A much smarter way is to replace the faulty device with a new one.
The lion's share of hard drives in the Russian (and not only) market is made up of products from IBM, Maxtor, Fujitsu, Western Digital (WD), Seagate, Quantum.

the name of the manufacturer producing this type of drive,

Corporation Quantum (www.quantum.com.), founded in 1980, is one of the veterans in the disk drive market. The company is known for its innovative technical solutions aimed at improving the reliability and performance of hard drives, access time to data on the disk and read / write speed on the disk, the ability to inform about possible future problems that could lead to data loss or disk failure.

- One of the proprietary technologies of Quantum is SPS (Shock Protection System), designed to protect the disc from shock.

- built-in program DPS (Data Protection System), designed to save the most expensive - the data stored on them.

Corporation Western Digital (www.wd.сom.) is also one of the oldest disk drive companies, it has known its ups and downs in its history.
Company for last time was able to incorporate the latest technologies into their drives. Among them, it is worth noting its own development-technology Data Lifeguard, which is a further development of the S.M.A.R.T. It attempts to logically terminate the chain.

According to this technology, the disk surface is regularly scanned during the period when it is not used by the system. In this case, the data is read and their integrity is checked. If problems are noted in the process of accessing a sector, the data is transferred to another sector.
Information about low-quality sectors is entered into an internal defect list, which makes it possible to avoid future writing to defective sectors in the future.

Firm Seagate (www.seagate.com) very well known in our market. By the way, I recommend the hard drives of this particular company as reliable and durable ones.

In 1998, she made a new comeback with the release of the Medallist Pro series.
with a rotation speed of 7200 rpm, using special bearings for this. Previously, this speed was only used in SСSI drives, which increased performance. In the same series, the SeaShield System technology is used to improve the protection of the disk and the data stored on it from the effects of electrostatics and shock. At the same time, the effect of electromagnetic radiation is also reduced.

All produced discs support S.M.A.R.T.
Seagate is considering an improved version of its SeaShield system with more features in the new drives.
Significantly, Seagate claims the industry's highest impact resistance for the revamped 300G when not in use.

Firm IBM (www. Storage. Ibm. Com) although until recently it was not a major supplier in Russian market hard drives, but quickly gained a good reputation for its fast and reliable hard drives.

Firm Fujitsu (www. Fujitsu.com) is a large and experienced manufacturer of disk drives, not only magnetic, but also optical and magneto-optical.
True, the company is by no means a leader in the market of hard drives with an IDE interface: it controls (according to various different studies) about 4% of this market, and its main interests lie in the field of SCSI devices.

Terminological dictionary

Since some parts of the drive that play important role in his work are often perceived as abstract concepts, below is an explanation of the most important terms.

Access time- the period of time required by the hard disk drive to search and transfer data to or from memory.
The performance of hard disk drives is often determined by the access (access) time.

Cluster (Сluster) Is the smallest unit of space that the OS operates with in the file location table. Typically a cluster consists of 2-4-8 or more sectors.
The number of sectors depends on the type of disk. Searching for clusters instead of individual sectors reduces operating system overhead in time. Large clusters provide faster performance
drive, since the number of clusters in this case is less, but at the same time the space (space) on the disk is used worse, since many files may be smaller than the cluster and the remaining bytes of the cluster are not used.

Controller (UU) (Сontroller)- circuits, usually located on an expansion board, that control the operation of the hard disk drive, including head movement and reading and writing data.

Cylinder- tracks located opposite each other on all sides of all discs.

Drive head- a mechanism that moves along the surface of a hard disk and provides electromagnetic recording or reading of data.

File Allocation Table (FAT)- a record generated by the OS, which keeps track of the placement of each file on the disk and which sectors are used and which are free to write new data to them.

Head gap- the distance between the drive head and the disk surface.

Interleave- the relationship between the speed of rotation of the disk and the organization of sectors on the disk. Typically, the rotation speed of the disk exceeds the computer's ability to retrieve data from the disk. By the time the controller reads data, the next sequential sector has already passed the head. Therefore, data is written to the disk in one or two sectors. With the help of a special software when formatting a disk, you can change the alternation order.

Logic drive- certain parts of the working surface of the hard disk, which are considered as separate drives.
Some logical drives can be used for other operating systems such as UNIX.

Parking (Park)- moving the drive heads to a certain point and fixing them in a stationary state over unused parts of the disk, in order to minimize damage when the drive is shaken when the heads hit the surface of the disk.

Partitioning- the operation of splitting a hard disk into logical disks. All disks are partitioned, although small disks can only have one partition.

Disc (Platter)- the metal disc itself, covered with a magnetic material, on which the data is recorded. Drive for hard drives usually has more than one disk.

RLL (Run-length-limited) Is a coding scheme used by some controllers to increase the number of sectors per track to accommodate more data.

Sector- the division of disk tracks, which is the basic unit of size used by the drive. OS sectors are usually 512 bytes.

Positioning time (Seek time)- the time required for the head to move from the track on which it is installed to any other desired track.

Track (Traсk)- concentric disc division. The tracks are like the tracks on a record. Unlike the tracks on a record, which are a continuous spiral, the tracks on a disc are circular. The tracks, in turn, are divided into clusters and sectors.

Track-to-track seek time- the time required for the drive head to move to an adjacent track.

Transfer rate- the amount of information transferred between the disk and the computer per unit of time. It also includes the track search time.

Novice users often have no idea at all about the partitions of their hard drive and logical drives of the hard drive. At first, this does not interfere with their work on the computer at all, although it does not allow them to use it more productively. But sometimes you have to deal with more responsible things, and then ignorance simple rules can turn into serious problems, up to the complete inoperability of the operating system and the loss of important data.

In fact, it is enough to remember a few simple things and keep this information in your head when you do any operations with hard disk partitions.

What is a section

To begin with, a new, freshly purchased hard drive is completely unusable without prior preparation. In order to be able to save data to it and read it, for this data you must first create special "storages" - sections, and prepare these "storages" for "warehousing" and storing your files - formatting, i.e. create on them file system... Once at least one partition is created and formatted, it can already be used.

Sometimes it happens that the hard drive has only one partition that occupies the entire hard disk. This is especially true for newbies who have just bought a computer. This option is the simplest, but also the most unsuccessful, because both the operating system and your data are stored in one place, and in case of any problems with the operating system, or when reinstalling the OS, you risk losing everything at once.

A more practical option is when the hard disk is divided into several partitions - at least two. One section contains the operating system itself, and the other stores your files. In this case, in case of problems or reinstallation of the operating system, only the partition on which it stood will suffer. Everything else will remain intact.

In addition, the division into several sections will make it more convenient to organize the storage of files - you can, for example, allocate a separate section for music or video if you have a lot of them; or if you often work with torrents, you can allocate a separate piece of your hard drive for them.

It also simplifies computer maintenance - for example, it is much easier and faster to defragment several relatively small partitions one at a time, rather than one huge chunk. The same applies to scanning the disk with an antivirus.

In general, we sorted it out with convenience - here everyone is free to contrive to the best of their needs. However, there are a few simple rules, violation of which can lead to complete loss of data.

I'll start in order.

Rule # 1

Just one hard disk can contain no more than 4 main sections, less is possible, more is not. These requirements do not depend on any operating system - they are dictated by the current level of development of the electronic filling of the computer. And it will not be possible to overcome them yet. If more than 4 sections are required, then another rule comes into force.

It was not in vain that I mentioned BASIC sections - this is not just a word, it denotes one of two types of sections. In addition to the main one, the section can also be additional (extended). And in this regard, the rule of 4 partitions is somewhat transformed - on one hard disk there can be up to 4 main sections, or up to 3 main sections plus one additional(there can be only one extended partition on a disk).

What does it give us? The fact is that an additional (extended) partition is, in fact, a container, inside which you can create an UNLIMITED number of logical disks. And for the user there will be absolutely no difference between working with the main partition and working with a logical disk. Thus, by creating an extended partition and logical drives inside it, we can divide the hard drive to fit our needs as we need it.

Please note that if you delete an extended partition, all logical drives included in it will also disappear.

Rule # 2

One of the sections is required it should be active (on Linux - have a flag boot). It is on it that the boot files that will start the operating system are located. At the same time, the system itself may be located in another place, but the files from which it starts to start are only there.

Most often, the first partition of the hard disk (disk C: / on Windows), but this is not required. In addition, you can always manually reassign any other main partition as active, but do not forget to move the boot files there, otherwise the operating system will not start.

Rule No. 3

If you are going to install several operating systems on one computer, then each of them should be installed in a separate section ( theoretically, you can put it in one, but subsequent problems after this cannot be avoided). Operating systems of the Windows family can be installed only on basic partitions. Accordingly, if you are going to install two Windows in multiboot mode, then they will occupy two main partitions. Linux operating systems do not have this limitation and can be installed anywhere.

File systems

Before using a partition, you need to format it - create a file system on it (mark it up in a special way).

There are quite a few file systems now, and all have different characteristics.

Operating systems of the Windows family can work only with FAT, FAT32 and NTFS file systems.

FAT is a very outdated system, and its use today is hardly justified. FAT32 more modern, but has serious limitations. which prevent its full use. For example, the maximum file size that FAT32 supports is about 4 GB. That is why, if you try, for example, to copy the image of a full-weight DVD disc to a flash drive ( which are formatted in FAT32 by default) You will receive a message that there is not enough free space, although in fact there is still a lot of space. Because of this, its use on sections where work with video takes place is almost impossible ( and under the section with torrents it is problematic to use it).

The file system is the best choice for Windows today. NTFS... It does not have such restrictions as FAT32, has additional security features, is more stable and reliable.

For UNIX, which includes Linux, there are many more file systems. Each of them has its own advantages and disadvantages and is more suitable for certain tasks. The default on Linux is ext4, but you can use any other. You can easily find information on which of the Linux file systems is most suitable for your tasks on the Internet.

A few words about compatibility

Windows does not understand any other file systems other than its own. Access from under it to Linux partitions was possible only with the help special programs or plugin to Total commander... Unfortunately, for the most modern Linux file systems, a plugin for Windows has not yet been written.

Linux, on the other hand, has always perfectly understood FAT and FAT32, and in the last 2-3 years it has been working without problems with NTFS through a special driver. NTFS-3g, both for reading and writing. Plus, it supports most of the additional opportunities NTFS. So from Linux you will always have full access to Windows partitions.

Mention should be made of the various household appliances- DVD players, satellite receivers, etc. All this technique can only work with FAT and FAT32. NTFS, and even more so UNIX file systems ( with extremely rare exceptions) are completely incomprehensible to her. This should be borne in mind if you exchange data between similar equipment and a computer.

Tools for the job

A few words about tools for working with sections.

I'll start with Windows. It includes a standard tool Disk management... You can get to it through Control Panel, or by right-clicking on the icon My computer => Control and choosing in the left column Disk management.

Please note that three sections in the screenshot are marked as unknown sections. These are partitions with Linux - Windows sees them, but it can neither define nor work with them.

also in Disk management you can clearly see the main and additional sections, as well as the active section ( marked as System- it contains boot files; the OS itself is installed in a partition labeled as - i.e. Windows swaps labels). Of all the possibilities, this tool provides only the creation and deletion of partitions, as well as reassigning the active partition and changing the drive letter ( in Vista and Windows 7 the functionality has slightly increased). If nothing else was at hand, then sometimes this is enough.

Important to remember , what Disk management- the tool is inconvenient, little functional and extremely dangerous, especially in inexperienced hands. It is assumed that the user who uses it knows exactly what he is doing, because any changes are applied immediately, no questions asked, and it is impossible to see in advance what these or those actions will lead to.

Therefore, I advise you to use it only as a last resort.

Various programs from the cohort have much greater capabilities, convenience and safety. Partition Magic-ov, for example,. There are quite a large number of such programs, they are all different and in recent years many of them have changed their owners-developers and their names. Therefore, if you decide to choose one of them for yourself, you will have to attend to an independent search on the wide open spaces of the Internet. It is not difficult, especially since the leaders in this field can be counted on one hand.

Acronis Disk Director Suite

In my opinion ( exclusively on my - t. To. many may have a different opinion on this matter), the most powerful and convenient program for working with hard disk and the sections are.

The program is Russian (although sometimes you come across its variants with English language) and very easy to use. At the same time, it fully provides the entire range of possible operations with a hard disk. In addition, almost all of your actions on the sections occur without losing the information that is on them.

All operations that you carry out over the sections are instantly displayed in a graphical form so that everything can be assessed visually. But the actions themselves are not performed in this case - only after you yourself evaluate everything, and the result completely and completely satisfies you, you can press the button " Apply". Up to this point, you can undo all actions step by step.

If several hard drives are connected to the computer, all of them will be shown in the program window - one above the other. The main sections are marked with green flags, and the active section is marked with a red flag.

Also, when running Acronis Disk Director Suite offers a choice of two modes of operation - automatic, in which all operations can be carried out with the help of "wizards", and manual mode, in which all power is at the mercy of the user. The second mode, IMHO, is more convenient and flexible, but beginners can also use the automatic one.

Also, the program contains a full and very detailed help.

One more possibility should be mentioned - from the program window you can create and burn a special bootable disk that will contain files Acronis Disk Director Suite... This thing is very convenient and extremely useful in the household - after all, having this disk completely eliminates the need to install the program itself and even have an operating system. From this disk you can boot your computer and perform any operations with partitions.

Now about the unpleasant. It consists in the fact that the program is relatively rarely updated, so sometimes situations arise when with the most modern hard drives it cannot work. This is more true for her version on boot disk since if Acronis Disk Director Suite installed in the operating system, then it will use drivers from Windows bundle... She also has some problems with Unix file systems - she does not understand the most modern file systems ( this can be seen in the screenshot below), although with old classics it works "with a bang".

Came out the other day a new version Acronis Disk Director Suite for English-speaking users (there is no new Russian version yet), which already works with the newest hard drives without any problems. But the problems with modern Unix file systems have not yet been resolved in it.

Gparted

Another powerful and versatile tool for working with a hard drive is the program Gparted from the Linux box.

It can be found on almost all Linux Live CDs.

The story about the program's capabilities can be summed up in one phrase: "Almost everything can be done." The interface is simple and unassuming, and the work is absolutely transparent and understandable. All your actions are also first displayed visually, and are performed only after pressing a special button, when you decide that everything suits you.

Besides, Gparted supports many more file systems, including the most modern ones.

If you have several hard drives, only one will be shown in the program window at a time. To work with others, use the drop-down list on the panel (on the right), which lists all connected hard drives.

Gparted cannot work with partitions that are currently mounted (there will be a warning icon next to such a partition). To perform any action on such partitions, you will first have to unmount them.

A few notes about the programs that are included in the installers of operating systems and can be used when installing the OS.

When installing Windows, all partitions of the hard disk will be visible exactly the same, without division into primary and extended. The only differences will be in labels and sizes, and it can be extremely easy to get confused. Therefore, it is advisable to use it only if you are installing the operating system on a new hard disk for the first time. If your disk has already been used, and it contains any information, it is best to take care of everything in advance in third party program, and actions in the installer can be reduced only to the selection of the desired partition and formatting (if necessary).

The situation is similar when installing Linux. Although everything is determined correctly there, it is not displayed very clearly, and the work is less transparent than in the same Gparted.

So it is best to create partitions of the desired size in the right place before installing and format them to any Linux file system, and when installing the OS, ignoring the automatic options offered and choosing manual partitioning, just mount them in the right places and change the file system to another if necessary by simply ticking the box Format opposite their sections.

For greater clarity, I recommend that you carefully study the screenshots for the article ( screenshots are clickable - when you click on them, full-size pictures will open in separate tabs). I draw your attention to the fact that everywhere it is depicted THE SAME hard disk, only in different programs... This disk has two parallel OS in multiboot mode - Windows and Linux, which coexist quite peacefully on one computer. Each of the operating systems has 3 sections ( separation is not perfect, but quite acceptable). Look carefully at what and how it looks in each of the programs.

Any hard disk includes: a plate (pancake, mirror) covered with a thin layer of magnetic material, a head unit (BMG), a mechanism that ensures high-precision installation of the heads on the desired sector, the case and the microcontroller board. A mirror pancake (there may be several of them), which stores the data, is attached to a rotating spindle. The heads always work in pairs - read and write. The positioning device is responsible for positioning the BMG relative to the surface of the magnetic plate. The case fixes all of the above elements and reliably protects them from external physical impact. The electronics board, on which the microcontroller is located, implements the functions of controlling the operation of all hard disk systems and is responsible for the two-way transport of information.

Hard drive geometry

Winchester plates can be cast from light metal alloys or ceramics. Each plane of the pancake (or working surface) is covered with a special magnetic substance, thanks to which the data is stored on the disk, and polished to a mirror finish. The composition of the feromagnetic material of each coating layer (layers, as a rule, several) is not the same and is a technological secret. Magnetic heads are located in the immediate vicinity of each working surface. To increase HDD performance, they always work in pairs, one for reading, the other for writing.

When formatting, a concentric notch is applied to the mirror, forming a kind of annular zones, which are called tracks. For convenience, each track with radii emanating from the center of the plate is divided into sectors (clusters). Any cluster consists of two conditional segments used to store service information and directly user data. The content of the service segment is formed once on the conveyor belt of the plant and is not subsequently rewritten. Among other things, the service segment contains the relative address of the entire sector on the surface of the plate. That is why the address is addressed to the cluster during read or write operations.

The clustered data segment is filled with information the user needs.

In other words, it stores pieces of those files that the owner of the drive writes to it. It is important to remember that the data segment of each sector is not capable of being overwritten in chunks. It will be updated completely, even if the size of the file copied to the hard drive is less than the allowable cluster data area.

In the case when a hard disk consists of several magnetic plates, experts are introducing another term into use - a cylinder. This word denotes a set of tracks located on different pancakes or adjacent working surfaces of one mirror and available for reading / writing without changing the position of the magnetic head unit. If we take into account that the positioning of the BMG does not occur instantaneously, then ideally located clusters of a single file should be within one cylinder.

Initially, each track, regardless of its proximity to the center, was divided into a fixed number of clusters. This allowed the controller to address the sector by indicating only its number and cylinder number, as well as the head that needs to perform the operation. If we draw an analogy with a three-dimensional region, then a kind of cylindrical coordinate system was formed on the plate, where its angle (sector number), height (head number) and radius (cylinder number) were indicated to determine a point in space. Continuing the analogy to the Cartesian region of three dimensions, we arrive at a model of a multi-storey building, each apartment in which is similar to the previous one and is identified by a separate number.

The indicated arrangement of the clusters practically three times reduced the recording density on the peripheral tracks, in relation to the inner ones. Taking this disadvantage into account, new form a surface marking in which the number of clusters on a track increases with distance from the center of the plate. This form of information recording was called zone and made it possible to almost double the amount of useful information volume, without increasing the geometric dimensions of the pancake and the relative density of the recording on its surface.

The resulting markup is now much more difficult to represent in the Cartesian coordinate system, so a hard disk formatted in this way was not always correctly detected by the BIOS. This is due to the fact that not every interface is able to correctly transform the cluster structure so that it is understandable for the motherboard firmware. It is for this reason that several disk interfaces - ST506 / 412, ESDI and others - came out of use, and over time were completely forgotten. With the introduction of the new layout geometry, only IDE and SCSI did not go away.

In fact, the procedure for transforming a chaotic circular structure into a neat 3D model is very similar to an insidious deception. For example, the BIOS limits maximum amount sectors on the track number 63, in reality there are much more clusters. The interface deceives the BIOS by presenting it with a fake address structure in which there are exactly 63 sectors on a track. The same substitution occurs with the number of heads. For the convenience of addressing, their number varies in the range from 16 to 255 pieces, in fact, there are rarely more than 6. With zone marking, the data exchange rate depends little on the proximity of the track to the center of the plate, its value will be more influenced by the cylinder number, in which contains clusters of information.

If you need, then contact us, we will help you with this problem.