The operating system, in addition to all other tasks, fulfills its main purpose - it organizes work with data according to a certain structure. For these purposes, the file system is used. What is a FS and what it can be, as well as other information about it will be presented below.
General Description
A file system is a part of the operating system that is responsible for placing, storing, deleting information on media, providing users and applications with this information, and ensuring its safe use. In addition, it is she who helps in data recovery in the event of a hardware or software failure. This is why the file system is so important. What is FS and what can it be? There are several types:
- for hard drives, i.e. devices with random access;
- for magnetic tapes, i.e. devices with serial access;
- for optical media;
- virtual systems;
- network systems.5
The logical unit of data storage in the file system is a file, that is, an ordered collection of data with a specific name. All data used by the operating system is presented in the form of files: programs, images, texts, music, videos, 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 apply to it, several main types of FS can be distinguished.
Programmatic approach
So, if the file system is considered (what it is and how to work with it), then it should be noted that this is a multi-level structure, at its top level there 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 accepted by the next level - drivers. They, in turn, access device-specific drivers, which store the necessary information.
Client-server applications have rather high performance requirements for FS. Modern systems are designed to provide efficient access, support for large-volume media, data protection from unauthorized access, and maintaining the integrity of information.
FAT file system
This type was developed back in1977 by Bill Gates and Mark McDonald. It was originally used in OS 86-DOS. If we talk about what the FAT file system is, then it is worth noting that initially it was not able to support hard drives, but only worked with flexible media up to 1 megabyte. Now this restriction is no longer relevant, and this FS was used by Microsoft for MS-DOS 1.0 and subsequent versions. FAT uses certain file naming conventions:
- the name must start with a letter or number, and it can contain any ASCII character, in addition to space and special elements;
- the length of the name should be no more than 8 characters, followed by a period, and then the extension is indicated, which consists of three letters;
- any case can be used in file names, it is not distinguished and not preserved.
Because FAT was originally designed for single-user DOS, it did not provide for storage of data about the owner or access rights. At the moment, this file system is the most widespread, most modern operating systems support it to one degree or another. Its versatility makes it possible to use it on volumes that are being worked on by different operating systems. This is a simple FS that is not able to prevent file corruption due to incorrect computer shutdown. As part of operating systems based on it, there are special utilities that check the structure andcorrect file inconsistencies.
NTFS file system
This FS is the most preferred for working with Windows NT, as it was developed specifically for it. The OS 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 has significantly expanded the ability to control access to certain directories and files, introduced many attributes, implemented dynamic file compression tools, fault tolerance, and supports the requirements of the POSIX standard. In this FS, you can use names up to 255 characters long, while a 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 in the event of an operating system failure, it is able to recover itself, so the disk volume will remain available, and the directory structure will not suffer.
NTFS features
On an NTFS volume, each file is represented by an entry in the MFT table. The first 16 table entries are reserved by the file system itself for storing special information. The very first entry describes the file table itself. When the first record is destroyed, the second one is read to find the mirror MFT file, where the first record is identical to the main table. The logical center of the disk contains a copy of the bootstrap file. The third entry in the table contains the log file, which is used for data recovery. In the seventeenth and subsequent entries of the file tablecontains information about the files and directories that are on the hard drive.
The transaction log contains a complete set of operations that change the volume structure, including operations to create files, 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 the directories and files that are in the root directory.
EFS features
The Encrypting File System (EFS) is a Windows feature that can store information on your hard drive 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 check the box in the properties of the folder or file. You can specify who can read such files. Files are encrypted when they are closed, and when they are opened, they are automatically ready for use.
RAW features
Devices designed for data storage are the most vulnerable components, which are most often subject to damage not only physically, but also logically. Certain hardware problems can be fatal, while others have solutions. Sometimes users have a question: "What is a fileRAW system?"
As you know, in order to write any information to a hard drive or flash drive, the drive must have a file system. The most common are FAT and NTFS. And RAW isn't even the file system we usually think of. 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 not only refuses access to data, but also does not display technical information on the equipment.
UDF Features
The 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, then this is a new implementation of the old version for optical discs, which meets the requirements of the International Organization for Standardization. It is characterized by certain features:
- filenames can be up to 255 characters long;
- the name can be lower or upper case;
- The maximum path length is 1023 characters.
Starting with Windows XP, this file system is read/write.
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 withdata received from the operating system, each of which has its own file system. What it is and how it works will be clear in practice.
Conclusions
As you can see from the above, each operating system uses certain file systems. They are intended for storing ordered data structures on physical media. If you suddenly, when using a computer, have a question about what the final file system is, then it is quite possible that when you tried to copy a certain file to the media, you received 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 you do not encounter problems when transferring information.
