Logical partition of the hard drive: essence and transformation. Types of logical hard disk partitions How many partitions can there be on a hard disk
When purchasing a computer or installing Windows or another OS, many users want to split the hard drive into two or, more precisely, into several partitions (for example, drive C into two drives). This procedure makes it possible to store system files and personal data separately, i.e. allows you to save your files in case of a sudden system crash and improve the performance of the OS by reducing fragmentation of the system partition.
Update 2016: new ways to split a disk (hard or SSD) into two or more have been added, a video has also been added on how to split a disk in Windows without programs and in the AOMEI Partition Assistant program. Corrections have been made to the manual. Separate instructions: .
You can split a hard drive or SSD into several partitions not only in Disk Management, but also using the command line in Windows 10, 8 and Windows 7.
Be careful: the example shown below will work without problems only in cases where you have a single system partition (and possibly a couple of hidden ones) that needs to be divided into two partitions - for the system and data. In some other situations (MBR disk and already have 4 partitions, when shrinking the disk, there is another disk "after" it) this may work unexpectedly if you are a novice user.
The following steps show how to split the C drive into two parts at the command prompt.
Done, now you can close the command line: in Windows Explorer you will see the newly created disk, or rather, the disk partition with the letter you specified.
How to partition a disk in Minitool Partition Wizard Free
Minitool Partition Wizard Free is an excellent free program that allows you to manage partitions on disks, including dividing one partition into two or more. One of the advantages of the program is that a bootable ISO image with it is available on the official website, which can be used to create a bootable flash drive (the developers recommend doing this using Rufus) or to burn a disc.
This makes it easy to perform disk partitioning in cases where this cannot be done on a running system.
After loading into Partition Wizard, you just need to right-click on the disk you want to split and select “Split”.
The next steps are simple: adjust the partition sizes, click OK, and then click the “Apply” button at the top left to apply your changes.
You can download the Minitool Partition Wizard Free bootable ISO image for free from the official website https://www.partitionwizard.com/partition-wizard-bootable-cd.html
Video instruction
I also recorded a video on how to partition a disk in Windows. It shows the process of creating partitions using standard system tools, as described above, and using a simple, free and convenient program for these tasks.
How to partition a disk during installation of Windows 10, 8 and Windows 7
The advantages of this method include its simplicity and convenience. Partitioning will also take relatively little time, and the process itself is very clear. The main disadvantage is that the method can only be applied when installing or reinstalling the operating system, which in itself is not very convenient; in addition, there is no possibility of editing partitions and their sizes without formatting the HDD (for example, in the case when the space of the system partition has run out and the user wants add some space from another hard drive partition). Creating disk partitions when installing Windows 10 is described in more detail in the article.
If these shortcomings are not critical, consider the process of disk partitioning during OS installation. These instructions are fully applicable when installing Windows 10, 8 and Windows 7.
Attention! When you delete disk partitions, all data located on them will be deleted.
Partitioning a hard drive when installing Windows XP
During the development of Windows XP, no intuitive graphical interface was created. But although control occurs through the console, partitioning the hard drive when installing Windows XP is as easy as when installing any other operating system.
Step 1. Delete existing partitions.
You can repartition the disk while defining the system partition. You need to split the section into two. Unfortunately, Windows XP does not allow this operation without formatting the hard drive. Therefore, the sequence of actions is as follows:
Step 2. Create new partitions.
Now you need to create the necessary hard disk partitions from the unallocated area. This is done quite simply:
Step 3. Determine the file system format.
After the partitions are created, select the partition that should be system and press Enter. You will be prompted to select a file system format. FAT format is more outdated. With it you will not have problems with compatibility, for example, Windows 9.x, however, due to the fact that systems older than XP are rare today, this advantage does not play a special role. If you also consider that NTFS is faster and more reliable and allows you to work with files of any size (FAT - up to 4GB), the choice is obvious. Select the desired format and press Enter.
Then the installation will proceed in standard mode - after formatting the partition, the installation of the system will begin on it. You will only be required to enter user parameters at the end of the installation (computer name, date and time, time zone, etc.). As a rule, this is done in a convenient graphical mode, so it is not difficult.
Free AOMEI Partition Assistant
AOMEI Partition Assistant is one of the best free programs for changing the structure of partitions on a disk, transferring a system from HDD to SSD, and, among other things, you can use it to split a disk into two or more. At the same time, the program interface is in Russian, unlike another good similar product - MiniTool Partition Wizard.
Note: despite the fact that the program claims to support Windows 10, on my system it did not partition for some reason, but no failures occurred (I think it should be fixed by July 29, 2015). Works without problems in Windows 8.1 and Windows 7.
After launching AOMEI Partition Assistant, in the main program window you will see the connected hard drives and SSDs, as well as the partitions on them.
To partition a disk, right-click on it (in my case on C), and select the “Partition Partition” menu item.
At the next step, you will need to specify the size of the partition to be created - this can be done by entering a number, or by moving the separator between the two disks.
After you click OK, the program will display that the disk has already been partitioned. In fact, this is not the case yet - to apply all the changes made, you must click the “Apply” button. You may then be warned that your computer will restart to complete the operation.
And after the reboot, you will be able to observe the result of disk separation in your Explorer.
Other programs for creating partitions on your hard drive
There is a huge amount of different software for partitioning a hard drive. These are both commercial products, for example, from Acronis or Paragon, and distributed under a free license - Partition Magic, MiniTool Partition Wizard. Let's look at dividing a hard drive using one of them - the Acronis Disk Director program.
How to partition a hard drive in MacOS X using standard means
You can partition your hard drive without reinstalling the operating system or installing additional software on your computer. In Windows Vista and higher, the disk utility is built into the system, and this is also the case in Linux systems and MacOS.
To partition a disk on Mac OS, do the following:
After this, after a short (for SSD anyway) partition creation process, it will be created and available in the Finder.
I hope the information is useful, and if something doesn't work as expected or you have questions, please leave a comment.
Beginner users often have no idea at all about the partitions of their hard drive and the 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 important things, and then ignorance of simple rules can result in serious problems, including complete inoperability of the operating system and loss of important data.
In fact, it is enough to remember a few simple things and keep this information in mind during any actions with hard drive partitions.
What is a section
Let me start with the fact that a new, freshly purchased hard drive is completely unsuitable for work without prior preparation. In order to be able to save and read data on it, you must first create special “storages” for this data - partitions, and prepare these “storages” for “warehousing” and storing your files - format them, i.e. create a file system on them. As soon as at least one partition is created and formatted, it can already be used.
Sometimes it happens that a hard drive has only one partition that occupies the entire hard drive. This can be observed especially often among beginners 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 if there are 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 drive is divided into several partitions - at least two. One partition contains the operating system itself, and the other stores your files. In this case, if there are problems or reinstallation of the operating system, only the partition on which it was located will be affected. Everything else will remain untouched.
In addition, dividing into several sections will allow you to more conveniently organize file storage - 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 sections in turn than to defragment one huge piece. The same applies to scanning a disk with an antivirus.
In general, we figured it out with convenience - here everyone is free to invent themselves to the best of their needs. However, there are several simple rules, violation of which can result in complete loss of data.
I'll start in order.
Rule #1
On just one hard drive there can be 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 computer electronics. 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 for nothing that I mentioned MAIN sections - this is not just a word, it means 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 about 4 partitions is somewhat transformed - on one hard drive there can be up to 4 main sections, or up to 3 main sections plus one additional(there can only be one extended partition on a disk).
What does this give us? The fact is that an additional (extended) partition is, in fact, a container within 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 suit 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 (in Linux - have a flag boot). It is on it that the boot files that will launch the operating system are located. The system itself may be located in another place, but the files from which it starts are only there.
Most often, the first partition of the hard disk becomes active (disk C:/ on Windows), but this is not a requirement. In addition, you can always manually reassign any other main partition as active, but you should not forget to move the boot files there, otherwise the operating system will not start.
Rule #3
If you are going to install several operating systems on one computer, then each of them should be installed on a separate partition ( theoretically, you can put it in one, but subsequent problems after this cannot be avoided). Operating systems of the Windows family can only be installed on primary 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 such a limitation and can be installed anywhere.
File systems
Before using a partition, you need to format it - create a file system on it (partition it in a special way).
There are quite a large number of file systems now, and they all have different characteristics.
Operating systems of the Windows family can only work 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 an image of a full-sized DVD disc to a flash drive ( which by default are formatted in FAT32) You will receive a message that there is not enough free space, although in fact there is still plenty of space there. Because of this, using it on sections where video work occurs is almost impossible ( and it’s problematic to use it under the section with torrents).
The best choice for working under Windows today is the file system NTFS. It does not have the same restrictions as FAT32, has additional security features, and is more stable and reliable.
For UNIXes, 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 one. You can easily find information on which Linux file system is most suitable for your tasks on the Internet.
A few words about compatibility
Windows does not understand any file systems other than its own. Access from under it to Linux partitions was possible only with the help of special programs or a plugin for Total Commander. Unfortunately, a plugin for Windows has not yet been written for the most modern Linux file systems.
Linux has always understood FAT and FAT32 very well, 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 features of NTFS. So from Linux you will always have full access to Windows partitions.
It is worth mentioning 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 remembered if you exchange data between such equipment and a computer.
Tools for work
A few words about the tools for working with partitions.
I'll start with Windows. It includes a standard tool Disk management. You can reach it through Control Panel, or by right-clicking on the icon My computer => Management and selecting in the left column Disk management.
Please note that three partitions in the screenshot are marked as unknown partitions. These are partitions with Linux - Windows sees them, but it cannot identify them, much less 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 marked as - i.e. Windows swaps labels). Of all the features, this tool only provides creating and deleting partitions, as well as reassigning the active partition and changing drive letters ( in Vista and Windows 7 the functionality has increased slightly). If there is nothing else at hand, then sometimes this is enough.
Important to remember , What Disk management- the tool is inconvenient, ineffective and extremely dangerous, especially in inexperienced hands. It is assumed that the user who uses it knows absolutely exactly what he is doing, because... any changes are applied immediately, without question, and it is impossible to see in advance what certain actions will lead to.
Therefore, I advise using it only in extreme cases.
Various programs from the cohort have much greater capabilities, convenience and security 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 owner-developers and their name. Therefore, if you decide to choose one of them for yourself, you will have to worry about searching on your own on the wide expanses of the Internet. This 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 mine - because Many people may have a different opinion on this matter.), the most powerful and convenient program for working with a hard drive and partitions is.
The program is Russian (although occasionally there are versions in English) and is very easy to use. At the same time, it fully provides the entire range of possible operations with the hard drive. In addition, almost all of your actions on partitions occur without losing the information located on them.
All operations that you perform on sections are instantly displayed graphically so that everything can be assessed visually. But the actions themselves are not performed - only after you evaluate everything yourself, and the result completely and completely satisfies you, you can press the " Apply". Up to this point, you can undo all actions step by step.
If several hard drives are connected to the computer, they will all 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.
In addition, when starting Acronis Disk Director Suite offers a choice of two operating modes - automatic, in which all operations can be carried out with the help of “masters”, and manual mode, in which all power is given to the user. The second mode, IMHO, is more convenient and flexible, but beginners can also use automatic.
The program also contains a complete and very detailed help.
One more possibility should be mentioned - from the program window you can create and burn a special boot 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, there is completely no 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 stuff. It lies in the fact that the program is updated relatively rarely, so sometimes situations arise when it cannot work with the most modern hard drives. This applies to a greater extent to its version on the boot disk, because If Acronis Disk Director Suite installed in the operating system, it will use the drivers included with Windows to work with the disk. She also has some problems with Unix file systems - she does not understand the most modern file systems ( this can be seen in the provided screenshot), although it works great with the old classic ones.
Recently a new version was released 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.
GParted
Another powerful and versatile tool for working with a hard drive is the program GParted from the Linux kit.
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 unpretentious, 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 you are satisfied with everything.
Besides, GParted supports a much larger number of 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 (a warning icon will appear opposite such a partition). To perform any actions with such partitions, you will first have to unmount them.
A few notes about the programs that are included in operating system installers and can be used when installing the OS.
When installing Windows, all partitions of the hard drive will be seen exactly the same, without division into primary and extended. The only differences will be in the marks and sizes, and it is extremely easy to get confused. Therefore, it is advisable to use it only if you are installing an operating system on a new hard drive for the first time. If your disk has already been used and there is any information on it, it is best to take care of everything in advance in a third-party program, and reduce the actions in the installer only to selecting the desired partition and formatting (if necessary).
The situation is similar when installing Linux. Although everything is defined correctly there, it is not displayed very clearly, and the work occurs less transparently than in the same GParted.
So it’s best to create partitions of the required size in the right place before installation and format them into any Linux file system, and when installing the OS, ignoring the proposed automatic options and choosing manual partitioning, simply mount them in the right places and change the file system to another if necessary , by simply checking a box Format opposite their sections.
For greater clarity, I recommend carefully studying the screenshots for the article ( screenshots are clickable - when you click on them, full-size pictures will open in separate tabs). Please note that everywhere is depicted THE SAME hard drive, only in different programs. On this disk, two operating systems are installed in parallel in multiboot mode - Windows and Linux, which coexist quite peacefully on one computer. Each operating system is allocated 3 sections ( separation is not ideal, but quite acceptable). Look carefully at what it looks like in each program.
) is usually practiced on the internal boot disks of a computer, since its main purpose is to separate the operating system files from the user's files and from the files of other operating systems located on the same physical medium, for example, in the case of a multiboot disk. However, the creation of multiple partitions can be supported by some operating systems on removable drives (USB-HDD), and, in some cases, even on USB MSC flash drives).
Benefits of Using Partitions
Allocating several partitions on one hard drive provides the following advantages:
- on one physical hard drive you can store information in different file systems, or in the same file systems, but with different cluster sizes (for example, it is advantageous to store large files - for example, video - separately from small ones, and set a larger cluster size for storing large files );
- manipulations with one section do not affect other sections;
- as a consequence, it is possible to separate user information from operating system files, and then:
- an image of an OS partition, used, for example, for backup before making significant changes to the OS configuration, will be smaller in size compared to the image of the entire disk, and restoring the system from the image will not affect user data that may have changed since the last time the image was taken;
- when reinstalling the OS “cleanly” (with complete destruction of the previous installation), no additional storage device is required for temporary storage of user data - the latter will remain unaffected;
- You can install multiple operating systems on one hard drive;
- reducing the impact of fragmentation on the speed of disk operations:
- with a smaller partition size, fragments of each file are distributed over less physical space, that is, file fragments are physically closer to each other, which reduces the time for positioning the disk head when accessing a file;
- There are fewer files on the partition, which results in [ ] to less fragmentation.
Partitioned disk structure
Information about the placement of partitions on the hard drive is stored in the partition table, which is part of the master boot record (MBR). The MBR is located in the first physical sector of the hard drive.
The section can be either primary (main), or additional.
In the first sector of each main (active) partition there is a boot sector (Boot Record), which is responsible for loading the operating system from this partition. Information about which of the main partitions will be used to boot the operating system is also recorded in the master boot record.
According to the rules, there can only be one additional section. Thus, in the maximum MBR configuration, three main partitions and one additional partition can be formed on the hard disk. However, some operating systems can only boot from the main partition; and those that can boot from an additional partition are forced to keep their bootloader on the main partition.
Additionally, some disk partitioning programs (such as fdisk in MS-DOS) do not support creating more than one primary partition.
Additional software allows you to bypass these restrictions ( partition managers).
In new PCs that have switched to EFI technology instead of Bios, there are no restrictions on the number of main partitions, and logical and extended partitions do not exist as unnecessary, since it is not the Master Boot Record that is used, but GPT (GUID Partition Table). Booting into this type of PC is carried out from a FAT32 partition with boot records.
Types of sections
Primary (main) section
In the early [ ] versions of Microsoft Windows The Primary partition (English Primary partition or English Basic partition) must have been present on the physical disk first. Accordingly, these operating systems could only be installed on the primary partition. This partition always contains only one file system. When using MBR, a physical disk can have up to four primary partitions.
Extended (additional) section
The main MBR partition table can contain no more than 4 primary partitions, so the Extended Partition (
No matter how advanced the operating system is, it is impossible to boot it without two sectors on the hard drive that contain the code necessary to run any operating system. The first sector is called Master Boot Record (MBR); it is always located at the address: sector 1/cylinder 0/head1 and is the very first sector of the hard drive. The second most important sector is the Boot Sector, located in the first sector of each volume.
Master Boot Record
Master Boot Record is the most important disk structure; this sector is created when a disk is partitioned. The MBR sector contains a small code called the Master Boot Code, as well as the disk signature and partition table. At the end of the MBR sector is a two-byte structure indicating the end of the sector. It has a value of 0x55AA. A disk signature is a unique number located at offset 0x01B8 and allows the operating system to uniquely identify this disk.
The code located in the MBR sector does the following:
- searches for the active partition in the partition table;
- searches for the starting sector of the active partition;
- loads a copy of the boot sector from the active partition into memory;
- transfers control to executable code from the boot sector.
- Invalid partition table;
- Missing operating system.
Partition table
A partition table is a 64-byte structure used to determine the type and location of partitions on a hard drive. The contents of this structure are unified and independent of the operating system. Information about each partition takes 16 bytes - thus, there can be no more than four partitions on the disk.
Each partition information starts at a specific offset from the start of the sector, as shown in table 1.
Offset
| |Meaning
|Description
0x01BE| 1 byte| 0x80| Boot Indicator - Indicates whether the volume is an active partition. May have the following values: 00 - not used for loading; 80 - active section
0x01BF| 1 byte| 0x01| Starting Head
0x01C0| 6 bit| 0x01| Starting Sector - bits 0-5 are used. Bits 6 and 7 are used by the following field
0x01C1| 10 bits| 0x00| Starting Cylinder - 10-bit number with maximum value 1023
0x01C2| 1 byte| 0x07| System ID - determines the volume type
0x01C3| 1 byte| 0xFE| Ending Head
0x01C4| 6 bit| 0xBF| Ending Sector - bits 0-5 are used. Bits 6 and 7 are used by the following field
0x01C5| 10 bits| 0x09| Ending Cylinder - 10-bit number with maximum value 1023
0x01C6| Double word| 0x3F000000| Relative Sectors - offset from the beginning of the disk to the beginning of the volume, expressed in the number of sectors
0x01CA| Double word| 0x4BF57F00| Total Sectors - the number of sectors in this volume
Now that we've looked at how a partition record works, let's take a closer look at some of the fields in that record.
Boot Indicator field
The first element of the partition table, the Boot Indicator field, indicates whether the volume is an active partition. We remind you that only the primary disk partition can be active. It is possible to install different operating systems and different file systems on different volumes. Using utilities such as FDISK (MS-DOS), Disk Management (Windows 2000) or third-party utilities, you can activate the primary partition and set the appropriate value for this field.
System ID field
This field contains the system ID and indicates which file system - FAT16, FAT32 or NTFS - was used to format the volume, and also allows you to find out some characteristics of the file system. In addition, this field shows whether an extended partition exists on the disk. Possible values for the System ID field are shown in table 3.
Partition type
|Explanations
0x01| Primary partition or logical drive FAT12. Volume has less than 32,680 sectors
0x04| FAT16 partition or logical drive. The volume has 32,680 to 65,535 sectors, or a size of 16 to 33 MB
0x05| Advanced section
0x06| BIGDOS FAT16 partition or logical drive. Size from 33 MB to 4 GB
0x07| NTFS partition or logical drive. Installable File System
0x0B| FAT32 partition or logical drive
0x0C| FAT32 partition or logical drive using BIOS INT 13h extensions
0x0E |BIGDOS FAT16 partition or logical drive using BIOS INT 13h extensions
0x0F| Extended partition using BIOS INT 13h extensions
0x12| EISA section
0x42 |Dynamic disk volume (Windows 2000)
Note that only volumes with a System ID field of 0x01, 0x04, 0x05 or 0x06 are accessible under MS-DOS. But volumes with a different System ID for this field can be deleted using the FDISK utility.
Cylinder, Head and Sector fields
The Starting Cylinder, Ending Cylinder, Starting Head, Ending Head, Starting Sector and Ending Sector (commonly known as CHS) fields are additional partition table elements. The boot code uses the values of these fields to find the boot sector and enable it. The Starting CHS fields of inactive partitions point to the boot sectors of the primary partitions and the extended boot sector of the first logical drive in the extended partition.
On rice. 2 shows the Master Boot Record (containing code, partition table and signature) and boot sectors for a disk with four partitions.
rice. 2
The Ending Cylinder field in the partition table has a size of 10 bits and allows you to describe cylinders with numbers from 0 to 1023. The Starting Head and Ending Head fields have a size of 1 bit and can contain head numbers from 0 to 255. Since the Starting Sector and Ending Sector fields occupy 6 bits each, they can contain values from 0 to 63. Since sector numbering starts from 1 (and not from 0, as for other fields), the maximum number of sectors on a track is 63.
Low-level formatting sets all disks to a standard sector size of 512 bytes, so the maximum disk size described in the partition table can be calculated as follows:
Code:
Maximum size = Sector size x Number of cylinders x Number of heads x x Number of sectors per track.
Using the maximum permissible values of these quantities, we obtain:
Code:
512 x 1024 x 256 x 63 (or 512 x 224) = = 8,455,716,864 bytes, or 7.8 GB.
Therefore, without the use of INT 13h extensions, known as Logical Block Addressing (LBA), the size of the active primary partition cannot exceed 7.8 GB, regardless of the file system used.
The maximum volume size under FAT16 depends on the disk geometry and the maximum values in the partition table. Possible values with and without LBA are shown in table 4. The number of cylinders in both cases is 1024 (0-1023). In the case where the primary partition or logical device occupies an area beyond the 1023rd cylinder, all fields of the partition table will have the maximum allowable values.
LBA mode
|Number of heads
|Sectors/Track
|Max. partition size
Banned| 64| 32| 1 GB
Allowed| 255| 63| 4 GB
To get around the 7.8 GB limitation described above, Windows 2000 ignores the Starting Sector and Ending Sector field values and uses the Relative Sectors and Total Sectors field values instead.
Relative Sectors and Total Sectors fields
The Relative Sectors field contains the offset from the beginning of the disk to the beginning of the volume, expressed in the number of sectors. The Total Sectors field indicates the total number of sectors in the volume.
Using the values of these two fields (which together are a 32-bit number), we get an additional 8 bits to store the total number of sectors compared to the CHS scheme described above. In this case, the number of sectors can be represented as 232. Using the standard sector size (512 bytes) and the 32-bit representation of the number of sectors, the maximum partition size is limited to 2 TB (or 2,199,023,255,552 bytes). This scheme is used only in Windows 2000 with NTFS and FAT32 file systems.
Note that when creating partitions under Windows 2000, the correct data is entered into the Starting Cylinder, Ending Cylinder, Starting Head, Ending Head, Starting Sector and Ending Sector fields. This allows compatibility with MS-DOS, Windows 95 and Windows 98, as well as with the INT 13h functions used by the BIOS when the computer boots.
Extended Boot Record
The Extended Boot Record (EBR) consists of an extended partition table and a signature - a two-byte structure with the value 0x55AA. An extended boot record exists for each logical device on an extended partition. It contains information about the first side of the first cylinder for each logical device. The boot sector of a logical disk is usually located in relative sectors numbered 32 or 63. If the disk does not have an extended partition, then there is no extended boot record and there are no logical devices.
The first element of the extended partition table for the first logical device points to its boot sector, the second element points to the EBR of the next logical device. If the next logical device does not exist, then the second element is not used - it contains a set of zeros. The third and fourth elements of the extended partition table are not used.
On rice. 3 shows how the extended boot record works. Shown are the three logical devices in the extended partition.
rice. 3
With the exception of the last logical device in the extended partition (see rice. 3), the extended partition table format described in table 5, is repeated for each logical device: the first element describes the boot sector of the logical device, the second element indicates the next extended boot record. For the last logical device, elements two through four are not used.
Extended Partition Table Element
|Contents
First element| Information about the current logical device in the extended partition, including the starting address for the data
Second element| Information about the next logical device in the extended partition, including the address of the sector containing the EBR for the next logical device. This field is not used if there are no following logical devices
Third element| Not used
Fourth element| Not used
The fields of each element in the extended partition table are similar to the fields of the regular partition table described above.
The Relative Sectors field in the extended partition table specifies, in bytes, the offset from the beginning of the extended partition to the first sector of the logical device. The number in the Total Sectors field allows you to find out the number of sectors allocated for the logical device. The value of the Total Sectors field is equal to the number of sectors from the beginning of the boot sector to the end of the logical partition.
Due to the exceptional importance of the information stored in the MBR and EBR sectors, it is recommended to periodically scan the disk using the appropriate utilities and create backup copies of the data.
Boot sector
The boot sector, located in sector 1 of each volume, is the structure that allows the computer to start. This sector contains the executable code and the data that the code requires, including information about the file system used on the volume. The boot sector is created when a volume is formatted. At the end of the boot sector is a two-byte structure called the end of sector marker. This structure always contains the value 0x55AA.
On computers running Windows 2000, the boot sector of the active partition is loaded into memory and calls the operating system loader - NTLDR, which performs all the necessary steps to boot Windows 2000.
In Windows 2000, the boot sector contains the following elements:
- JMP assembly instruction;
- manufacturer identifier (OEM ID);
- a data structure called the BIOS Parameter Block (BPB);
- expanded BPB structure;
- executable code that runs the operating system.
The BPB structure contains the physical parameters of the volume, the extended BPB structure begins immediately after the standard BPB. The length of the BPB structure and the information it contains depends on the type of boot sector - NTFS, FAT16 or FAT32.
The information stored in the BPB and the extended BPB structure is used by device drivers to read and configure volumes.
Immediately following the extended BPB structure is the boot code.
Boot process
The computer boot process consists of the following basic steps:
- When the power is turned on, a BIOS and processor verification test is performed - POST.
- The BIOS looks for a boot device (usually a disk).
- The BIOS loads the first physical sector from the boot disk into memory and transfers control to the address where this sector is loaded.
If there is a disk in drive A, the BIOS loads the first sector (boot sector) of that disk into memory. If the disk is bootable (contains the base files of the operating system), the boot sector is loaded into memory and uses code to transfer control to the file IO.SYS - the base file of the MS-DOS operating system. If the disk is not bootable, the executable code in the boot sector produces the following message:
- Non-System disk or disk error
- Replace and press any key when ready
Types of boot sectors
As we already know, the MBR transfers control to the boot sector. Therefore, the first three bytes of this sector must contain a valid instruction for the CPU. This instruction is a jump instruction that redirects code execution. The JMP instruction is followed by an 8-byte OEM ID, a string that describes the name and version number of the operating system used to format the volume.
To maintain compatibility with MS-DOS, Windows 2000 records the identifier "MSDOS5.0" for FAT16 and FAT32 file systems. For the NTFS file system, the identifier contains the characters "NTFS".
Windows 95 uses the "MSWIN4.0" identifier, while Windows 95 OSR2 and Windows 98 use the "MSWIN4.1" identifier.
Immediately following the manufacturer ID is a data structure called the BIOS Parameter Block (BPB). It contains the information needed to locate the NTLDR file. Since the BPB is usually located at the same offset, the standard parameters are easily detected. Since the JMP instruction bypasses the BPB structure, its size can be increased in the future if any additional information needs to be stored here.
Now let's look at what boot sectors look like for the three main file systems - FAT16, FAT32 and NTFS.
FAT16 boot sector
IN table 6 A description of the boot sector for the FAT16 file system is provided.
Offset
| |0x00| 3 bytes| JMP instruction
0x03| 2 x LONG| OEM ID
0x0B| 25 bytes| BPB
0x24| 26 bytes| Extended BPB
0x3E| 448 bytes| Boot code
A specific example shows the contents of the FAT16 boot sector. There are three sections here:
- bytes 0x00-0x0A contain the JMP instruction and OEM ID (highlighted in font);
- bytes 0x0B-0x3D contain BPB and extended BPB;
- the remaining bytes contain the boot code and the end of sector marker (highlighted in font).
The following two tables show the contents of the BPB ( table 7) and extended BPB ( table 8) for FAT16. The values given correspond to the boot sector shown in Fig. 4.
Offset
| |Meaning
|Description
0x0D| 1 byte| 0x40| Number of sectors in the cluster. Because FAT16 supports a limited number of clusters (up to 65,536), larger volumes require more sectors to be used in the cluster. The default value of this field depends on the volume size. Valid values are: 1, 2, 4, 8, 16, 32, 64, and 128. Values that increase the cluster size to more than 32 KB (the number of bytes per sector multiplied by the number of sectors in the cluster) may cause errors
0x0E| 2 bytes| 0x0100| Reserved sectors - the number of sectors before the first FAT table, including the boot sector. The value of this field is always 1
0x11| 2 bytes| 0x0002| The total number of 32-byte file and directory names that can be stored in the volume's root directory. Typically the value of this field is 512. One element is always used to store the volume label, so the maximum number of files and directories does not exceed 511
0x13| 2 bytes| 0x0000| The number of sectors in the volume, expressed as a 16-bit value. For volumes with more than 65,536 sectors, this field is not used and its value is 0
0x16| 2 bytes| 0xFC00| The number of sectors in each copy of the FAT. The value of this field, the number of FAT copies, and the number of reserved sectors are used to calculate the location of the root directory. Knowing the maximum number of entries in the root directory can also tell you where user data begins
0x1A| 2 bytes| 0x4000| Number of heads. Used for low-level disk formatting
0x1C| 4 bytes| 0x3F000000| The number of “hidden” sectors is the number of sectors before the boot sector. Used at boot time to calculate the absolute offset of the root directory and data
0x20| 4 bytes| 0x01F03E00| The number of sectors in the volume, expressed as a 32-bit value. Used for volumes that have more than 65,536 sectors
Offset
| |Meaning
|Description
0x24| 1 byte| 0x80| Physical device number. Contains 0x00 for floppy disks and 0x80 for hard disks. Use INT 13h to access the disk. The value of this field is only meaningful for the boot device
0x25| 1 byte| 0x00| Reserved. For FAT16, the value of this field is always 0
0x26| 1 byte| 0x29| Extended boot sector signature. For Windows 2000 this field should be 0x28 or 0x29
0x27| 4 bytes| 0xA88B3652| Volume serial number. Random number generated when disk is formatted
0x2B |11 bytes| NO NAME| Volume label. In Windows 2000, the volume label is stored in a special file
0x36| 2 x LONG| FAT16| File system type. Depending on the disc format, this field may contain the characters FAT, FAT12 or FAT16
rice. 4
FAT32 boot sector
The FAT32 boot sector has many similarities with the FAT16 boot sector, but the BPB contains additional fields, and those fields used in FAT16 are located at different addresses. Thus, drives formatted with FAT32 cannot be read by operating systems that are not compatible with FAT32.
IN table 9 shows the contents of the boot sector for the FAT32 file system.
Offset
| |Meaning
|Description
0x0B| 2 bytes| 0x0002| The number of bytes in a sector is the sector size. Valid values are 512, 1024, 2048, and 4096. For most drives, this field is 512
0x0D| 1 byte| 0x40| Number of sectors in the cluster. Because FAT32 supports a limited number of clusters (up to 4,294,967,296), very large volumes require the use of more sectors per cluster. The default value of this field depends on the volume size. Valid values are 1, 2, 4, 8, 16, 32, 64, and 128. In Windows 2000, FAT32 supports volumes up to a maximum size of 32 GB. Larger volumes created with Windows 95 OSR2 and Windows 98 are accessible from Windows 2000
0x0E| 2 bytes| 0x0200| Reserved sectors - the number of sectors before the first FAT table, including the boot sector. The value of this field for FAT32 is usually 32
0x10| 1 byte| 0x02| The number of copies of FAT tables for this volume. The value of this field is always 2
0x11| 2 bytes| 0x0000| The total number of 32-byte file and directory names that can be stored in the volume's root directory (FAT12/FAT16 only). For FAT32 volumes, this field should be 0
0x13| 2 bytes| 0x0000| The number of sectors in the volume, expressed as a 16-bit value (FAT12/FAT16 only). For FAT32 volumes, this field should be 0
0x15| 1 byte| 0xF8| Media type. A value of 0xF8 indicates a hard drive, 0xF0 indicates a high-density floppy drive. This field is not used in Windows 2000
0x16| 2 bytes| 0x0000| Number of sectors in each copy of FAT (FAT12/FAT16 only). For FAT32 volumes, this field should be 0
0x18| 2 bytes| 0x3F00| Number of sectors in a track. Used for low-level disk formatting
0x1A| 2 bytes| 0xFF00| Number of heads. Used for low-level disk formatting
0x1C| 4 bytes| 0xEE39D700| The number of “hidden” sectors is the number of sectors before the boot sector. Used at boot time to calculate the absolute offset of the root directory and data
0x20| 4 bytes| 0x7F324E00| The number of sectors in the volume, expressed as a 32-bit value. Used for volumes that have more than 65,536 sectors
0x24| 4 bytes| 0x83130000| Number of sectors in FAT (FAT32 only)
0x28| 2 bytes| 0x0000| Extended flags (FAT32 only). The individual bits of this word have the following meaning: bits 0-3 - number of active FATs; bits 4-6 - reserved; bit 7 is equal to 0 if FAT “mirroring” is performed; equals 1 if only one FAT is active; bits 8-15 - reserved
0x2A| 2 bytes| 0x0000| File system version (FAT32 only)
0x2C| 4 bytes| 0x02000000| The cluster number for the first cluster of the root directory (FAT32 only). Typically the value of this field is 2
0x34| 2 bytes| 0x0600| Sector number with a backup boot sector (FAT32 only). Typically the value of this field is 6
0x36| 12 bytes| 0x0000000000000000000000000| Reserved (FAT32 only)
table 10.
Offset
| |0x00| 3 bytes| JMP instruction
0x03| 2 x LONG| OEM ID
0x0B| 25 bytes| BPB
0x24| 48 bytes| Extended BPB
0x54| 426 bytes| Download Code
0x01FE| 2 bytes| End of sector marker (0x55AA)
table 12.
For NTFS volumes, the fields following the BPB are the extended BPB block. The data contained here helps NTLDR locate the MFT table during boot. Unlike FAT16 and FAT32, MFT is not located in a fixed location - its location can change, for example when bad sectors are detected. If the MFT cannot be found, Windows 2000 assumes that the drive is unformatted.
IN table 13 The BPB and extended BPB fields for NTFS volumes are presented. The fields at offsets 0x0B, 0x0D, 0x15, 0x18, 0x1A, and 0x1C are identical to the fields for FAT16 and FAT32 volumes. The values given correspond to the boot sector shown in rice. 6.
Offset
| |Meaning
|Description
0x0B| 2 bytes| 0x0002| Number of bytes per sector
0x0D| 1 byte| 0x08| Number of sectors in a cluster
0x0E| 2 bytes| 0x0000| Reserved sectors
0x10| 3 bytes| 0x000000| Always 0
0x13| 2 bytes| 0x0000| Not used in NTFS
0x15| 1 byte| 0xF8| Media type
0x16| 2 bytes| 0x0000| Always 0
0x18| 2 bytes| 0x3F00| Number of sectors per track
0x1A| 2 bytes| 0xFF00| Number of heads
0x1C| 3 bytes| 0x3F000000| Number of “hidden” sectors
0x20| 4 bytes| 0x00000000| Not used in NTFS
0x24| 4 bytes| 0x80008000| Not used in NTFS
0x28 |2 x LONG| 0x4AF57F0000000000| Total number of sectors
0x30| 2 x LONG| 0x0400000000000000| Logical cluster number for file $MFT
0x38| 2 x LONG| 0x54FF070000000000| Logical cluster number for file $MFTMirr
0x40 |4 bytes| 0xF6000000| Number of sectors in a file write segment
0x44| 4 bytes | 0x01000000| Number of clusters in index block
0x48| 2 x LONG| 0x14A51B74C91B741C| Volume serial number
0x50| 4 bytes| 0x00000000| Check sum
Sometimes you need to create an additional partition on the disk ( split it) for example, for a second operating system or to separate system files from user ones. This way, you can ensure their safety if something happens to your computer. I will show you how to create a partition in Windows itself through disk management and during its installation.
I'm looking forward to the question: won't the files be deleted from the disk from which the partition will be created? No, they will not be deleted and it will work exactly the same. You will take only part of the free space and a partition will be created from it.
Creating a partition in Disk Management
Open the run bar Start >> Run (or Win + R) and enter the command that will open the Disk Control Panel.
Then you will see all disks and partitions. To create a new one you need free space ( green area) or unallocated space ( black area).
I only have 118 megabytes of unallocated space - this is certainly not enough, which means I need to take free space from a free disk. In this case C.
Before doing this, it is highly advisable to do this, otherwise the space may not be allocated at all. In the context menu, click “Shrink Volume” and wait.
Select a size for the volume. 5000 megabytes is enough for me for Windows XP. For Windows 7, 8 and 10 - at least 16 gigabytes. More is better if you plan to actively use the system.
As a result, such an unallocated black area should appear.
Make a section out of it. To do this, right-click on it and select “Create simple volume” as in the image below.
The built-in volume creation program will open. Move on.
You will be asked to choose a size from the available space. I choose 5000 MB to install Windows XP. This size is for demonstration only, you can put much larger to make it comfortable to work with.
Then assign an unassigned letter to avoid confusion.
After this you need to perform formatting.
- File system - NTFS.
- Cluster size is default.
- Volume Label - Enter the name of your operating system to avoid confusion later. I'm going to install Windows XP there, that's what I called it.
Finish creating the partition.
A partition with a blue area will then appear, which can be used when installing Windows or for storing files. I prepared it specifically for Windows XP.
It can also be seen as an additional disk by going to My Computer explorer.
Now all that remains is to install the operating system. You can also create a partition directly during ( see below).
The same instructions can be viewed in video format. All actions are carried out on the Windows 7 operating system.
Creating a partition during Windows installation
I believe that this method is much more convenient and simpler than others, as it allows you to do everything at once during the installation process. But if you just want to split the disk into several, then this method is unlikely to suit you. The instructions are applicable for versions of Windows 7, 8 and 10. Their installation interface is almost the same.
As soon as you select the language and accept the license agreement, a window with section settings will appear. In it you need to create a new one by clicking on the corresponding button as shown below and assign its size.
If you do not have unallocated space and there are still partitions, then delete them using the corresponding button. They will be converted and a new partition can be made from them. Please note that all data on them will be permanently deleted.
Then select the created partition and click next to proceed to the simple installation process.
Partitioning a disk using a program
Most programs for working with hard drives are paid, but there is also a free solution in Russian. That's what I'll look at now.
Download AOMEI Partition Assistant Standard and install. It is very convenient to divide, create and change partitions. In addition to this, the program has many other features, but in this article I will look at how to divide a disk into 2 or more. You can check out the rest of the features yourself.
All disks and partitions are located on the main screen. Select the one you want to split, and then from the context menu, click split partition.
In the window that appears, set the size. For example, I have 256 megabytes installed.
Now you need to confirm the changes. To do this, on the main screen, click “Apply” and a window will appear in which there will be a warning that a reboot is required. After it, changes will occur and you will be able to see the result.
I think these methods are enough to solve this problem. Ask your questions in the comments.
How did you create the section?