Menu
homeBrowsers

File system organization. The concept of "file", "directory". Requirements for file and directory names. Full file name. File types. Use of symbols. The concept of a file. File name, extension and specification

File system

File is any set of information saved on disk under its own name. The file can be programs, texts, pictures, data sets, etc. Files are stored on disk in a hierarchical tree structure.

Disks are designated by letters of the Latin alphabet and a colon. A hard drive can be divided into several logical drives, which are designated by letters C:, D:, E: etc.

Essentially, a folder is a special type of file that contains information about the files and folders within it.

Address indicates the location of a file or folder on the file system. It starts with the drive name and then records a sequence of folder names. The disk name is called root directory. Another name for an address is “full path”.

Address recording format: Drive name:\Folder1\Folder2\.

Full file name consists of the file name and full path. Every file stored on your computer has a unique full name. There cannot be two files with the same names in one folder; this is acceptable in different folders.

Files are written to disk in parts. The smallest space that can be written to a disk is one cluster is the minimum addressable disk element. A cluster can consist of one or more sectors. The sector size is 512 bytes.

The file storage system is called file system. Windows supports three file systems: FAT16 (or simply FAT), FAT32 and NTFS. The file system is selected when installing Windows and formatting the disk.

When formatting a disk, a system area is allocated, which consists of three parts: the boot sector, the file allocation table and the root directory.

IN boot sector(Boot Record) stores data about the disk format and its file system.

IN root directory contains a list of files located on the disk. A file record contains the name of the file, the address of the first cluster, the size of the file, and the time and date of its creation.

File Allocation Table(File Allocation Table, abbreviated FAT) contains a description of the order of location of all files in the clusters of a given disk, as well as information about defective areas of the disk. The number of cells in the FAT table corresponds to the number of clusters on the disk, and the values ​​of the cells are the file placement chains, i.e. sequence of addresses of clusters in which files are stored. The sequence number of the FAT table cell corresponds to the cluster address.

The file name consists of two parts separated by a dot: the file name and its extension.

Extension in the file name serves to indicate its type. The OS identifies the program by its file extension. With which the file was created. Some extensions indicate that the file is a program.


Program files are called executable files. They have an extension com or exe.

The use of the following service characters in the file name is prohibited: \ / : * ? “< > |.

There are some differences in specifying file names in MS DOS and Windows. In MS DOS, the name length should not exceed 8 characters, in Windows - 256 characters. In MS DOS you cannot use Russian alphabet characters and spaces, but in Windows you can.

Wildcard characters are used to designate a group of files. An asterisk (*) denotes any number of characters, a question mark (?) denotes any one character. For example, the pattern p* means that the file name begins with the letter p, the pattern p???l means that the file name contains any three characters between the letters p and l, and the pattern *.txt denotes all files with the txt extension.

Some programs use the pipe character (|) to indicate the exclusion of certain patterns. For example, *.*|*.bak means all files except files with the bak extension.

The computer works with information, which can be text, graphic, audio or video format. All information processed on a computer is stored in files. The concept of a file is one of the basic concepts of computer literacy.

File is a named area of ​​memory on computer storage media. In other words, a file is a set of data on computer media (hard drive, CD and DVD drive, flash drive, etc.), which has its own name ( file name).

What characters can be used in a file name? It is recommended to use Russian and Latin letters, numbers, spaces and punctuation marks in file names. However, the file name should not begin with a period, nor should it use square brackets or curly braces ( ) in the name. The following service characters are invalid for file names: / \ | : * ? “< >

Is there a maximum filename length? The file name length must not exceed 255 characters. In fact, 20-25 characters are usually enough.

Windows does not differentiate between lowercase and uppercase letters for file names. This means that you cannot store files whose names differ only in case in the same directory. For example, two file names "Title.doc" and "TITLE.doc" for Windows will be the same name for the same file.

Do you think there can be several files with the same name PRIMER in one directory? This is possible provided that the PRIMER name has different extensions.

File name extension points to file type(sometimes they also say - file format). Thus,

  • "file type",
  • "file format",
  • "file extension",
  • “file name extension” –

this is, by and large, the same thing.

For example,

PRIMER.doc(x) – the file type is a Word document (or a file in Word format),

PRIMER.bmp – the file type is a picture,

PRIMER.avi – the file type is a video file,

PRIMER.wav – The file type is an audio file.

All these files have different names (due to different file name extensions) and can be stored in the same place, i.e. in one directory. If we draw an analogy with people's names, then the file name is the same as the person's name, and the file name extension is the person's last name. Accordingly, PRIMER.doc and PRIMER.bmp by this analogy are the same as Ivan Petrov and Ivan Sidorov. Files with the names PRIMER.doc and VARIANT.doc are two brothers from the same document family (with the same .doc extension), just as, for example, Ivan Petrov and Fedor Petrov are brothers from the same Petrov family.

The file name extension is the part of the file name that begins with a period followed by several characters.

Extensions consisting of three letters are common - .doc, .txt, .bmp, .gif, etc. Case does not matter, so .doc and .DOC are the same document extension.

The extension is an optional attribute in the file name, i.e. it may not exist. In this case, there is usually no dot at the end of the file name. The extension, although not necessary, is still desirable, because it tells Windows what type of file it is. Simply put, the file type tells Windows which program to open the file with. For example, the .doc extension indicates that the file should be opened using the Word editor, and the .cdr extension indicates that the file should be opened with the Corel Draw graphics program.

There are reserved (service) names that cannot be used as file names because they are device names:

PRN – printer,

COM1-COM4 – devices connected to serial ports 1-4,

AUX – same as COM1,

LPT1-LPT4 – devices connected to parallel ports 1-4 (usually printers),

CON (consol) – for input – keyboard, for output – screen,

NUL is an “empty” device.

Here are examples of file names that are invalid:

5<>8/7.txt – symbols "<», «>" and "/" are prohibited,

What's the question? - symbol "?" prohibited

PRN.bmp – here PRN is a reserved name.

Depending on the file type, different icons are displayed on the Windows screen:

Windows Explorer (Start-Programs-Accessories-Explorer) by default has a mode where file name extensions are not displayed on the screen, but file icons are displayed.

When saving a file, just write its name and select the file type from the available list. The selected extension will automatically be added to the file name. For example, in the figure below, the program itself will add the .jpg extension to the file name. As a result, Windows will remember this file with the name “drawing in paint.jpg”.

To avoid misunderstandings when saving files, always pay attention to the “file type” line, if there is one. After all, the file type is a hint for Windows, with the help of which the system determines which program this file can be opened.

If you downloaded a file from the Internet, for example, with the extension .rar, but you do not have an archiver program installed on your computer to work with such “compressed, archived” files, then do not be surprised that the file does not open. In other words, you need to be aware that if you open files, for example, in a video format, then the computer must have the appropriate program to work with this format.

An analogy can be drawn between a file (more precisely, between a file type) and a program that works with that type of file. A file is a lock, and the program that opens this file is a key. A lock cannot be opened without a key, and a key without a lock is not particularly valuable.

Computer literacy exercises:

1) Try creating two folders on your Desktop with the names: PRIMER and primer. To do this, on the Desktop, right-click on an empty space, and in the window that appears, click on the “Create” option and, finally, click on the “Folder” option. Replace "New Folder" with "PRIMER". Then repeat all this to create a second folder called “primer”. Did Windows give you the go-ahead to open a second folder?

2) For example, go to Word editor and try saving the document with the name PRN. Does Windows allow this name for a new file?

3) How to solve the problem: “I download files from the Internet, but they are in xsd (PM)/RAR format and cannot be opened or read on the computer. What to do?"

P.S. The article is over, but you can still read:

Receive the latest computer literacy articles directly to your inbox.
Already more 3,000 subscribers

.

(FS), usually called catalog, directory or folder. File names are built according to the rules adopted in a particular file and operating systems(OS). Many systems allow you to assign names to both regular files and directories and special objects ( symbolic links , block devices and so on.).

The file name is part full file name, also called complete or in an absolute way to the file. The full name may include the following components:

The file name is necessary so that the user can access the file. There cannot be two files with the same name in the same directory (some file systems are case-insensitive, which leaves the possibility of creating files whose names differ in case).

The file name consists of two parts separated by a dot:

File names on different systems

Full, or absolute, is the name of the file containing all directories up to the root of the file system. Relative filenames do not contain the full path and are usually bound to current directory.

Windows

  • \ - subdirectory separator
  • / - shell key separator
  • : - separates the drive letter or name of an alternate data stream
  • * - replacement character (mask "any number of any characters")
  • ? - replacement character (mask "any one character")
  • " - used to specify paths containing spaces
  • < - перенаправление ввода
  • > - output redirection
  • | - denotes conveyor

IN UNIX and UNIX-like OSes, the slash (/) - subdirectory separator - and the end-of-line character (\0) are prohibited. The characters listed above (except for the slash) can be used, but for compatibility reasons it is better to avoid them.

File name extension

File name extension (English filename extension, they often say simply file extension or extension) - a sequence of characters added to the file name and intended to identify the type ( format) file. This is one of the common ways in which user or software The computer can determine the type of data stored in the file. The extension is separated from the main part of the file name by the latter dot. Sometimes several extensions may be used, following each other, for example, ".tar.gz".

OS or file manager can match file extensions and applications. When a user opens a file with a registered extension, the program corresponding to that extension is automatically launched. Some extensions may indicate that the file is executable (on Windows).

see also

Literature

  • Robachevsky A. N., Nemnyugin S. A., Stesik O. L. File names / Basic file system System V / Chapter 4. File system // UNIX operating system. - 2nd ed. - St. Petersburg. : BHV-Petersburg, 2008. - pp. 338-339. - 656 s. - ISBN 978-5-94157-538-1

Wikimedia Foundation. 2010.

  • Yasaka-jinja
  • Dubovik

See what “File name” is in other dictionaries:

    File attributes- a set of bytes that distinguishes a file from many other files. The file attributes are: file name and content type; date and time of file creation; file owner name; file size; file access rights; file access method. See also:… … Financial Dictionary

    File name extension- (English filename extension, often simply called file extension or extension) a sequence of characters added to the file name and intended to identify the type (format) of the file. This is one of the common methods, with... ... Wikipedia

    file transfer- Transferring a file from one directory or folder to another. Often, when transferring, the user changes the file name. As a result, the file is written in a new location and erased in the old one. In contrast, when you copy a file, it appears in a new location... ...

    X file format- a file format for storing 3D objects created by Microsoft. This format stores information about the geometry of a 3D object (vertex coordinates and normal coordinates), texture coordinates, descriptions of materials, paths and names to textures that ... Wikipedia

    File format- Format specification of the structure of data recorded in a computer file. The file format is usually indicated in its name, as a part separated by a dot (this part is usually called the file name extension, although strictly speaking this is not true). For example,... ... Wikipedia

    file attributes- Identifiable file attributes (name, etc.) [E.S. Alekseev, A.A. Myachev. English-Russian explanatory dictionary on computer systems engineering. Moscow 1993] Topics information technology in general EN file attributes ... Technical Translator's Guide

A file is a certain amount of information (program or data) that has a name and is stored in long-term (external) memory.

The file name consists of two parts, separated by a dot: the actual file name and the extension that determines its type (program, data, etc.). The actual name of the file is given by the user, and the file type is usually set automatically by the program when it is created. File extension is the part of the file name separated by the rightmost dot in the name.

When writing a file name, you are allowed to use only English letters and numbers. The name must begin with a letter. Spaces and punctuation are not allowed, with the exception of the exclamation mark (!), tilde (~), and underscore (_).

After the introduction of the Windows 95 operating system, file naming requirements became significantly more relaxed. They are also valid in all subsequent versions of Windows operating systems.

1. Up to 255 characters are allowed.

2. It is allowed to use symbols of national alphabets, in particular Russian.

3. Spaces and other previously prohibited characters are permitted, with the exception of the following nine: /\:*?"<>|.

4. You can use multiple periods in the file name. The name extension is all characters after the last dot.

The role of the file name extension is purely informational, not command-oriented. If you assign the file extension TXT to a file with a picture, then the contents of the file will not turn into text. It can be viewed in a program designed for working with texts, but such viewing will not give anything intelligible.

File system. Each storage medium (floppy, hard or laser disk) can store a large number of files. The order in which files are stored on the disk is determined by the installed file system.

A file system is a system for storing files and organizing directories. It defines the format for the physical storage of information, which is usually grouped in the form of files. A specific file system determines the size of the file name, the maximum possible file size, and a set of file attributes. Some file systems provide service capabilities, such as access control or file encryption.

For disks with a small number of files (up to several dozen), it is convenient to use a single-level file system, when the directory (disk table of contents) is a linear sequence of file names. To find a file on disk, you just need to specify the file name. This single-level scheme was used in the first versions of MS-DOS. Today it can be found, for example, in some digital cameras: all photographs taken are stored in one catalog.

If hundreds and thousands of files are stored on a disk, then for ease of searching, the files are organized into a multi-level hierarchical file system, which has a “tree” structure (looks like an inverted tree).

In this case, files on disks are combined into directories. The initial, root, directory contains subdirectories of the 1st level, in turn, in each of them there are subdirectories of the 2nd level, etc. It should be noted that files can be stored in directories of all levels. In Windows, directories are called folders

File attributes are set for each file and tell the system what operations can be performed on the files. There are four attributes:

Read Only (R);

Archive (A);

Hidden (H);

System (S).

Read-only file attribute

This attribute indicates that the file cannot be modified. All attempts to modify, delete, or rename a read-only file will fail.

File attribute "Hidden"

A file with this attribute is not displayed in the folder. The attribute can also be applied to entire folders. We must remember that the system provides the ability to display hidden files; to do this, just go to the Explorer menu Tools - Folder Options - View tab - Show hidden files and folders.

File attribute "Archive"

Almost all files have this attribute; enabling/disabling it makes virtually no sense. Used by backup programs to detect changes to a file.

File attribute "System"

This attribute is set for files that are required by the operating system for stable operation. In effect, it makes the file hidden and read-only. It is impossible to set the system attribute for a file yourself.

FILE SPECIFICATION

In order for the operating system to detect a file, it needs to be told

his name. In addition, you must specify the drive where the file is located. For

The disk designation uses the cipher of the device (disk drive) on which

it is installed. The device code is a letter of the alphabet, for

followed by a colon. The first drive in the system is assigned

the code is "A:", the second - "B:". The first hard disk drive is usually

is marked with the code "C:". Disk drives differ in the device encryption and

are called: drive A, drive B, etc.

The device cipher, written in combination with the file name, represents

is a file specification. The specification is entered in the format: ("cipher

device""simple name.extension"). For example, a file specification with

simple name "instruct" and extension "txt", located on drive A,

looks like this: "A:instruct.txt".

File system types

According to the method of data identification, they are distinguished:

Trivial file systems that determine the storage of files in a single “heap”, the root directory of the media. These systems have practically died out and have been replaced by hierarchical ones. Among the ones used can be called TR-DOS on the Sinclair ZX-Spectrum computer.

Hierarchical file systems that provide storage of files in a tree-like directory structure. They are the most common type of FS. Since the 1990s, almost exclusively they have been used in desktop systems.

Relational, associative, (?) other FSs that provide other methods of data identification. They are used extremely rarely due to the narrow scope of application.

File systems vary in their resilience to failures:

Fault-tolerant structures are usually trivial structures, the full consistency of which is not always ensured during operation. If the system fails during moments of inconsistency, data loss or even destruction of the entire file system is possible. Recovery often requires lengthy and non-trivial actions.

Failure-tolerant systems present fully consistent structures at any time during the life of the file system, so there are no moments when a failure can lead to data loss or destruction of the file system. As a rule, these are journaled file systems that duplicate all structure changes in a special area - the journal, thus, in the event of a failure, they have the ability to complete an unfinished operation or reverse the state of the file system before the failure.