File system

File system is a part of the operating system that works with files and provides storage of data on disks and access to them. That is, any file system is designed to store information about the physical location of parts of the file.

File system is a part of the operating system that works with files and provides storage of data on disks and access to them

The most important aspect of the file system is the naming and protection of files, operations with them, etc. The computer does not care what name a program or document has - it gets an instruction from the operating system like this: "read so many bytes from such and such a place on the disk." In this case, the user does not have to know the details of the operation of the disks, in which physical order and where exactly his data are located.

What are the rules for naming files? All modern file systems support the use of 8-character text strings as file names, many up to 255 characters.

The file name can consist of two parts, separated by a dot. The part of the name after the dot is called the file extension and indicates its type. In some operating systems, file extensions are simply conventions and are not strictly adhered to.

In order to logically group files, you need a certain general hierarchy, i.e. tree of catalogs. In this case, each user can create himself as many directories and subdirectories as he needs.

When organizing a file system in the form of a directory tree, each file can be given an absolute path name, consisting of the names of all directories - from the root directory to the one in which the file itself is contained. The relative pathname is also used. It is used in conjunction with the concept of the current directory. The user can assign one of the directories to the current working directory. In this case, all path names that do not begin with the delimiter character are considered relative and are counted relative to the current directory.

Each file system has a minimum unit of information - a cluster whose size is the lower limit of the size of the information written to the media. A larger cluster size ensures higher performance by reducing the file system itself.

The file system must clearly perform the following actions: determine the physical location of the parts of the file; determine the availability of space and allocate it for newly created files.

Different file systems use different mechanisms to implement these tasks. File system type FAT (File Allocation Table) is a carrier image in a thumbnail, where the detail is carried out to the cluster level. Therefore, the operation of finding the physical coordinates of a file with its large fragmentation is difficult. The FAT16 file system occupies a volume of 128 KB - this makes it easy to cache its information. For FAT32, this value is approximately 1 MB, which makes it even more difficult to find the physical coordinates of a fragmented file. The NTFS (New Technology File System) file system uses a more compact form of writing, which speeds up file searching. The key advantage of NTFS is the ability to restrict access to files and folders.

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