The operating system, in addition to all other tasks, performs its main purpose - it organizes work with data on a specific structure. For these purposes, the file system is used. What is a FS and what can it be, as well as other information about it will be presented below.
general description
The file system is a part of the operating system that is responsible for placing, storing, deleting information on media, providing this information to users and applications, as well as ensuring its safe use. In addition, it helps to recover data in the event of a hardware or software failure. Therefore, the file system is so important. What is FS and what can it be? There are several types:
- for hard drives, that is, devices with random access;
- for magnetic tapes, that is, devices with sequential access;
- for optical media;
- virtual systems;
- network systems. 5
As a logical unit for storing data in the file system, a file is used, that is, an ordered set of data with a specific name. All data used by the operating system is presented in the form of files: programs, images, texts, music, video, as well as drivers, libraries and more. Each such item has a name, type, extension, attributes, and size. So now you know what a file is. A 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, several main types of FS can be distinguished.
Program approach
So, if you are considering a file system (what is it and how to work with it), then you need to note that it is a multi-level structure, at its upper level is a file system switch that provides an interface between the system and a specific application. It converts file requests into a format that is perceived by the next level - drivers. They, in turn, turn to the drivers of specific devices that store the necessary information.
For client-server applications, the requirements for FS performance are quite high. Modern systems are designed to provide effective access, support for large storage media, protect data from unauthorized access, preserve the integrity of information.
FAT file system
This type was developed back in 1977 by Bill Gates and Mark MacDonald. It was originally used on the 86-DOS OS. If we talk about what the FAT file system is, then it is worth noting that initially it was not able to support hard disks, but worked only with flexible media up to 1 megabyte in size. Now this restriction is no longer relevant, and this FS was used by Microsoft for MS-DOS 1.0 and later. FAT uses certain conventions in terms of file naming:
- at the beginning of the name there must be a letter or number, and any ASCII character can be present in it, in addition to a space and special elements;
- the length of the name should be no more than 8 characters, a dot is put after it, and then the extension, which consists of three letters, is indicated;
- any register can be used in file names, it does not differ and is not saved.
Since FAT was originally designed for single-user DOS, it did not provide for the storage of owner data or access permissions. At the moment, this file system is most widely distributed, to one degree or another it is supported by most modern operating systems. Its versatility makes it possible to use it on volumes with which various OSs work. This is a simple file system that is not able to prevent damage to files due to incorrect shutdown of the computer. The operating systems based on it contain special utilities that check the structure and correct file inconsistencies.
NTFS file system
This FS is the most preferable for working with Windows NT, since it was developed specifically for it. The operating system includes the convert utility, which converts volumes with FAT and HPFS to NTFS volumes. If we talk about what the NTFS file system is, it is worth noting that it significantly expanded the ability to control access to certain directories and files, introduced many attributes, implemented dynamic file compression tools, fault tolerance, and supported the requirements of the POSIX standard. In this FS, you can use names up to 255 characters long, while the short name in it is generated in the same way as in VFAT. Understanding what the NTFS file system is, it is worth noting that if the operating system crashes, it can recover itself, so the disk volume will remain available, and the catalog structure will not be affected.
NTFS Features
On an NTFS volume, each file is represented by an entry in the MFT table. The first 16 records of the table are reserved by the file system itself for storing special information. The very first record describes the file table itself. When the first record is destroyed, the second is read to search for the MFT mirror file, where the first record is identical to the main table. On the logical center of the disk is a copy of the boot file. The third record of the table contains the registration file, which is used to restore data. In the seventeenth and subsequent entries of the file table is information about files and directories that are on the hard drive.
The transaction log contains a complete set of operations that change the structure of the volume, including file creation operations, as well as any commands that affect the directory structure. The transaction log is designed to recover NTFS from a system crash. The entry for the root directory contains a list of directories and files that are in the root directory.
EFS Features
The Encrypted File System (EFS) is a component of Windows that can be used to save information on the hard disk 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, for this you only need to select the checkbox in the properties of the folder or file. You can specify who can read such files. Encryption occurs when closing files, and when they open, they automatically become ready for use.
RAW Features
Devices designed for data storage are the most vulnerable components, which are most often subject to damage not only in the physical plane, but also in the logical one. Certain equipment problems can be fatal, while others have some solutions. Sometimes users ask themselves: "What is the RAW file system?"
As you know, to record any information on the hard drive or flash drive, the drive must have a file system. The most common are FAT and NTFS. And RAW is not even the file system that 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 file system structure. After that, the OS not only denies access to data, but also does not display technical information on the equipment.
UDF Features
Universal Disc Format (UDF) is designed to replace CDFS and add support for DVD-ROM devices. If we talk about what the UDF file system is, then this is a new implementation of the old version for optical disks, which meets the requirements of the International Organization for Standardization. It is characterized by certain features:
- the length of file names can be up to 255 characters;
- the case of the name 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 that 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, it will be clear already in practice.
conclusions
As is clear from the above, in each operating system certain file systems are used. They are intended for storage of ordered data structures on physical information carriers. If you suddenly have a question when using a computer about what the final file system is, then it is quite possible that when you try to copy a specific file to the media, you will see a message about exceeding the allowed size. That is why it is necessary to know in which file system what file size is considered acceptable, so that when transferring information you do not encounter problems.