File system - what is it? File system NTFS, FAT, RAW, UDF

The operating system, in addition to all other tasks, fulfills its main purpose - it organizes the work with data on a certain structure. For these purposes, the file system is used. What is the FS and what it can be, as well as other information about it will be presented further.

general description

A file system is part of the operating system that is responsible for storing, storing, deleting information on media, providing users and applications with this information, and ensuring its safe use. In addition, it is it that helps in recovering data in the event of a hardware or software failure. Therefore, the file system is so important. What is FS and what it can be? There are several types:

- for hard disks, i.e. devices with random access;

- for magnetic tapes, that is, devices with sequential access;

- for optical media;

- virtual systems;

- network systems.5

A logical unit of data storage in a file system is a file, that is, an ordered data set having a specific name. All the data used by the operating system are represented in the form of files: programs, images, texts, music, video, as well as drivers, libraries and so on. Each such element has a name, type, extension, attributes and size. So now you know what a file is. The file system is a collection of such elements, as well as ways to work with them. Depending on the form in which it is used and what principles are applicable to it, it is possible to distinguish several basic types of FS.

The program approach

So, if the file system is considered (what is it and how to work with it), then it should be noted that this is a multi-level structure, at its upper level there is a file system switch that provides an interface between the system and a particular application. It converts requests to files in a format that is perceived by the next level - the drivers. They, in turn, turn to the drivers of specific devices that store the necessary information.

In client-server applications, the performance requirements for FS are quite high. Modern systems are designed to provide effective access, support for large volumes of data, protect data from unauthorized access, and preserve the integrity of information.

FAT File System

This type was developed back in 1977 by Bill Gates and Mark McDonald. Originally it was used in OS 86-DOS. If we talk about what the FAT file system is, it's worth noting that initially it was not able to support hard disks, but worked only with flexible media up to 1 megabyte. Now this restriction is irrelevant, and this FS was used by Microsoft for MS-DOS 1.0 and later. FAT uses certain conventions in terms of naming files:

- at the beginning of the name there must be a letter or number, and in it can be any ASCII character, in addition to the space and special elements;

- the length of the name should be no more than 8 characters, after it a dot is put, and then an extension that consists of three letters is indicated;

- in file names any register can be used, it does not differ and is not saved.

Since FAT was originally designed for a single-user DOS OS, it did not provide for storage of data about the owner or access rights. At the moment, this file system is distributed most strongly, to some extent it is supported by most modern operating systems. Its versatility makes it possible to use it on the volumes with which the different operating systems work. This is a simple FS, which is not capable of preventing file corruption due to incorrect shutdown of the computer. As part of the operating systems that run on its basis, there are special utilities that check the structure and correct inconsistencies of files.

NTFS file system

This FS is most preferred for working with Windows NT, as it was developed specifically for it. The OS includes the convert utility, which converts volumes from FAT and HPFS to NTFS volumes. If we talk about what the NTFS file system is, it's worth noting that it significantly enhances the ability to control access to certain directories and files, introduced many attributes, implemented file compression tools dynamically, failsafe, supports the POSIX standard. In this FS, you can use names up to 255 characters long, while the short name is generated in the same way as in VFAT. Understanding what the NTFS file system is, it's worth noting that in the event of an operating system failure, it can recover itself, so the disk volume will remain accessible, and the catalog structure will not suffer.

NTFS Features

On an NTFS volume, each file is represented by a record in the MFT table. The first 16 table entries are reserved by the file system for storing special information. The very first record describes the file table itself. When the first record is destroyed, the second record is read to search for the MFT mirror file, where the first record is identical to the main table. A copy of the boot file is placed on the logical center of the disk. The third entry in the table contains the log file that is used to restore the data. The seventeenth and subsequent entries in the file table contain information about the files and directories that are available on the hard disk.

The transaction log contains a complete set of operations that change the structure of the volume, including the operations for creating files, as well as any commands that affect the directory structure. The transaction log is designed to recover NTFS as a result of a system failure. The entry for the root directory contains a list of directories and files that are in the root directory.

Features of EFS

The Encrypting File System (EFS) is a Windows component through which information on the hard disk can be stored in an encrypted format. Encryption has become the strongest protection that this operating system can offer. In this case, encryption for the user is a fairly simple action, this requires only checking the box in the properties of the folder or file. You can specify who can read such files. Encryption occurs when files are closed, and when they open, they automatically become ready for use.

RAW Features

Devices intended for data storage are the most vulnerable components, which are most often damaged not only physically, but also logically. Certain problems with the equipment can be fatal, and others have some solutions. Sometimes users have a question: "What is the RAW file system?"

As you know, to write to a hard disk or flash drive of any information, the drive must have a FS. The most common are FAT and NTFS. And RAW is not even a file system, which we usually imagine. In fact, this is a logical error of an already installed system, that is, its actual absence for Windows. Most often RAW is associated with the destruction of the structure of the file system. After that, the OS does not simply deny access to data, but also does not display technical information about the equipment.

Features of UDF

Universal disk format (UDF) is designed to replace CDFS and add support for DVD-ROM devices. If we talk about what the UDF file system is, it is a new implementation of the old version for optical disks that meets the requirements of the International Organization for Standardization. It is characterized by specific features:

- file names can be up to 255 characters long;

- the name register can be lower and upper;

- The maximum path length is 1023 characters.

Starting with Windows XP, this file system supports reading and writing.

What is the EXFAT file system

This FS is used for flash drives, which are supposed to be used when working with different computers running different operating systems, in particular Windows and Linux. It was EXFAT that became the bridge between them, since it is able to work with data received from the OS, each of which has its own file system. What is and how it works will be clear already in practice.

conclusions

As you can see from the above, each operating system uses certain file systems. They are designed to store ordered data structures on physical media. If you suddenly wonder when using a computer about what a finite file system is, it is quite possible that when you try to copy a specific file to a medium, you see a message about the exceeding of the allowed size. That is why it is necessary to know in which FS what size of files is considered acceptable, so that when transferring information, do not face problems.