File: file names. Full, short, long, correct and incorrect file name, its composition, pattern and mask. Test on the topics “Files and file system” Rules for naming

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, as a rule, there is 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 this 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 the 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

.

File system - the order that determines the way data is organized, stored and named on storage media in computers, as well as in other electronic equipment: digital cameras, mobile phones etc. The file system determines format contents and method of physical storage of information, which is usually grouped in the form files. The specific file system determines the size of the file name ( folders), maximum possible file and partition size, set attributes file. Some file systems provide service capabilities, e.g. access control or encryption files.

In a broad sense, the concept of "file system" includes:

• the totality of all files on the disk,
• · sets of data structures used to manage files, such as file directories, file descriptors, free and used disk space allocation tables,
• · a set of system software tools that implement file management, in particular: creation, destruction, reading, writing, naming, searching and other operations on files.

A file is a concept familiar to any computer user. For the user, each file is a separate object, which has a beginning and an end and which differs from all other files in name and location (“what is it called” and “where is it located”). Like any object, a file can be created, moved and destroyed, but without external intervention it will remain unchanged indefinitely. The file is designed to store data of any type - text, graphics, sound, executable programs and much more. The analogy of a file with an object allows the user to quickly get comfortable when working with data in the operating system.

File names:

Files are identified by names. Users give files symbolic names, taking into account OS restrictions on both the characters used and the length of the name. Until recently, these boundaries were very narrow. Thus, in the popular FAT file system, the length of names is limited to the well-known 8.3 scheme (8 characters - the name itself, 3 characters - the name extension), and in the UNIX System V OS, the name cannot contain more than 14 characters. However, it is much more convenient for the user to work with long names, since they allow you to give the file a truly mnemonic name, by which, even after a fairly long period of time, you can remember what this file contains. Therefore, modern file systems tend to support long symbolic file names. For example, Windows NT, in its new NTFS file system, specifies that a file name can be up to 255 characters long, not counting the terminating null character.

Long names are supported not only by new file systems, but also by new versions of well-known file systems. For example, Windows 95 uses the VFAT file system, which is a significantly modified version of FAT. Among many other improvements, one of the main advantages of VFAT is its support for long names. In addition to the problem of generating equivalent short names, when implementing the new version of FAT, an important task was the problem of storing long names, provided that the storage method and the structure of the data on the disk should not fundamentally change.

Typically, different files can have the same symbolic names. In this case, the file is uniquely identified by a so-called compound name, which is a sequence of symbolic directory names. Some systems cannot give the same file multiple different names, while others have no such restriction. In the latter case, the operating system assigns an additional unique name to the file so that a one-to-one correspondence can be established between the file and its unique name. The unique name is a numeric identifier and is used by operating system programs. An example of such a unique file name is an inode number on a UNIX system.

File types:

Files come in different types: regular files, special files, directory files.

Regular files, in turn, are divided into text and binary. Text files consist of strings of characters represented in ASCII code. These can be documents, source codes of programs, etc. Text files can be read on the screen and printed on a printer. Binary files do not use ASCII codes and often have complex internal structures, such as program object code or an archive file. All operating systems must be able to recognize at least one file type - their own executable files.

Special files are files associated with I/O devices that allow the user to perform I/O operations using normal commands for writing to or reading from a file. These commands are first processed by file system programs, and then at some stage of the request execution they are converted by the OS into control commands for the corresponding device. Special files, like I/O devices, are divided into block-oriented and byte-oriented.

A directory is, on the one hand, a group of files combined by the user based on some considerations (for example, files containing game programs, or files that make up one software package), and on the other hand, it is a file containing system information about a group of files. its components. The directory contains a list of files included in it, and a correspondence is established between the files and their characteristics (attributes).

Different file systems may use different characteristics as attributes, for example:

• information about permitted access,
• · password to access the file,
• · file owner,
• · file creator,
• "read-only" sign
• · "hidden file" sign,
• · "system file" sign,
• · sign "archive file",
• · sign "binary/character",
• · “temporary” sign (remove after process completion),
• · blocking sign,
• record length,
• · pointer to the key field in the record,
• · key length,
• · times of creation, last access and last modification,
• current file size,
• · maximum file size.

Directories can directly contain the values ​​of file characteristics, as is done in the MS-DOS file system, or refer to tables containing these characteristics, as is implemented in the UNIX operating system.

Directories can form a hierarchical structure due to the fact that a lower-level directory can be included in a higher-level directory.

/libhistory.so.5.2

(Hierarchical file system in Unix and UNIX-like operating systems):

The directory hierarchy can be a tree or a network. Directories form a tree if a file is allowed to be included in only one directory, and a network if a file can be included in several directories at once. In MS-DOS, directories form a tree structure, and in UNIX they form a network structure. Like any other file, a directory has a symbolic name and is uniquely identified by a compound name containing a chain of symbolic names of all directories through which the path from the root to this directory passes.

Logical file organization:

The programmer deals with the logical organization of a file, representing the file in the form of logical records organized in a certain way. A logical record is the smallest piece of data that a programmer can manipulate when exchanging with an external device. Even if the physical exchange with the device is carried out in large units, the operating system provides the programmer with access to a separate logical record. Figure 2.33 shows several diagrams of the logical organization of a file. Records can be fixed length or variable length. Records can be arranged in a file sequentially (sequential organization) or in a more complex order, using so-called index tables, allowing quick access to an individual logical record (index-sequential organization). A special field in the record called a key can be used to identify a record. In UNIX and MS-DOS file systems, a file has the simplest logical structure - a sequence of one-byte records.

Physical organization and file address:

Physical file organization describes the rules for placing a file on an external storage device, particularly on a disk. A file consists of physical records - blocks. A block is the smallest unit of data that an external device exchanges with RAM. Continuous placement is the simplest variant of physical organization (Figure 2.34a), in which a file is provided with a sequence of disk blocks that form a single continuous section of disk memory. To specify the file address in this case, it is enough to specify only the starting block number. Another advantage of this method is its simplicity. But there are also two significant drawbacks. Firstly, when creating a file, its length is not known in advance, which means it is not known how much memory should be reserved for this file, and secondly, with this placement order, fragmentation inevitably occurs, and disk space is not used efficiently, since individual Small areas (minimum 1 block) may remain unused.

The next method of physical organization is placement of disk memory blocks in the form of a linked list (Figure 2.34b). With this method, at the beginning of each block there is a pointer to the next block. In this case, the file address can also be specified by one number - the number of the first block. Unlike the previous method, each block can be attached to a chain of any file, therefore there is no fragmentation. The file can change during its existence, increasing the number of blocks. The disadvantage is the complexity of implementing access to an arbitrarily specified location in the file: in order to read the fifth block of the file in order, it is necessary to sequentially read the first four blocks, tracing the chain of block numbers. In addition, with this method, the amount of file data contained in one block is not equal to a power of two (one word is consumed for the next block number), and many programs read data in blocks whose size is equal to a power of two.

A popular method, used for example in the FAT file system of the MS-DOS operating system, is to use a linked list of indexes. Each block is associated with a certain element - an index. Indexes are located in a separate area of ​​the disk (in MS-DOS this is a FAT table). If a certain block is allocated to a certain file, then the index of this block contains the number of the next block of this file. With this physical organization, all the advantages of the previous method are preserved, but both noted disadvantages are removed: firstly, to access an arbitrary location in the file, it is enough to read only the index block, count the required number of file blocks along the chain and determine the number of the desired block, and, secondly , the file data occupies the entire block, which means it has a volume equal to a power of two.

In conclusion, let's consider specifying the physical location of the file by simply listing the block numbers occupied by this file. UNIX OS uses a variant of this method that allows for a fixed address length, regardless of the file size. There are 13 fields allocated to store the file address. If the file size is less than or equal to 10 blocks, then the numbers of these blocks are directly listed in the first ten fields of the address. If the file size is more than 10 blocks, then the next 11th field contains the address of the block in which another 128 numbers of the next blocks of the file can be located. If the file is larger than 10+128 blocks, then the 12th field is used, which contains the block number, containing 128 block numbers, which each contain 128 block numbers of this file. And finally, if the file is larger than 10+128+128 (128), then the last 13th field is used for triple indirection, which allows you to specify the address of a file that has a maximum size of 10+ 128 + 128(128 + 128).

File permissions:

Defining access rights to a file means defining for each user a set of operations that he can apply to a given file. Different file systems can have their own list of differentiated access operations. This list may include the following operations:

• · creating a file,
• · file destruction,
• · opening a file,
• · closing the file,
• · reading a file,
• · writing to a file,
• · file addition,
• · search in a file,
• · getting file attributes,
• · setting new attribute values,
• · renaming,
• file execution
• · reading the directory,

and other operations with files and directories.

In the most general case, access rights can be described by an access rights matrix, in which the columns correspond to all files in the system, the rows correspond to all users, and at the intersection of rows and columns the permitted operations are indicated (Figure 2.35). In some systems, users may be divided into separate categories. Unified access rights are defined for all users of the same category. For example, in a UNIX system, all users are divided into three categories: the owner of the file, members of his group, and everyone else.

General file system model:

The functioning of any file system can be represented by a multi-level model, in which each level provides a certain interface (set of functions) to the upper level, and itself, in turn, uses the interface (handles a set of requests) of the lower level to perform its work.

The task of the symbolic level is to determine from the symbolic file name its unique name. In file systems in which each file can have only one symbolic name (for example, MS-DOS), this level is absent, since the symbolic name assigned to a file by the user is both unique and can be used by the operating system. In other file systems, where the same file can have multiple symbolic names, this layer traverses the directory chain to determine a unique file name. In the UNIX file system, for example, the unique name is the file's inode number (i-node).

At the next, basic level, the unique file name determines its characteristics: access rights, address, size, and others. As already mentioned, file characteristics can be part of a directory or stored in separate tables. When a file is opened, its characteristics are moved from disk to RAM to reduce the average file access time. In some file systems (for example, HPFS), when a file is opened, the first few blocks of the file containing data are moved into RAM along with its characteristics.

The next stage of implementing a request to a file is checking access rights to it. To do this, the authorities of the user or process that issued the request are compared with the list of allowed types of access to this file. If the requested type of access is allowed, then the request continues; if not, a message about access rights violation is issued.

At the logical level, the coordinates of the requested logical record in the file are determined, that is, it is necessary to determine at what distance (in bytes) from the beginning of the file the required logical record is located. In this case, the physical location of the file is abstracted; it is represented as a continuous sequence of bytes. The operating algorithm of this level depends on the logical organization of the file. For example, if a file is organized as a sequence of logical records of fixed length l, then the n-th logical record has an offset of l((n-1) bytes. To determine the coordinates of a logical record in a file with an index-sequential organization, the index (key) table is read, in which the address of the logical record is directly indicated.

Option 1

1.The file is:

2.The file name consists of two parts:

B) name and extension

3.The file name is:

A) operating system

B) processor

C) the program when it was created

D) user

4. The extension is assigned to the file:

A) the program when it was created

B) processor

B) user

D) operating system

5.The file name can include up to

A) 16 characters

B)254 characters

B) 256 characters

D) 255 characters

6. Allotted for expansion

A) 4 characters

B) 2 characters

B) 3 characters

D) 5 characters

7.In order for files to be stored on the disk, the disk must first be:

A) copied

B) formatted

B) deleted

D) difragmented

8.During the formatting process, the disk is divided into two areas:

A) name and extension

B) storage area and directory

B) RAM and cache memory

D) sectors and tracks

9.Single-level file system

10.Path to file

D) begins with the logical name of the disk, then a sequence of names of folders nested within each other is written, the last of which contains the desired file

A) to shell programs

D) applications

B) about the volume of the disk

14.Where the currently running program and processed data are stored

A) in external memory

B) in the processor

B) in RAM

D) on the output device

15.A directory is a place on a disk named and containing

B) files and other directories

B) only certain files

A) ALT+DEL keys

B) CTRL+DEL keys

B) when you turn on the computer

D) DEL key

17. The operating system is:

A) in numbers

B) letters and numbers

B) in Russian letters

D) in Latin letters

19.The root directory is

A) first top

B) the lowest

B) the most important

D) the biggest

20.The file path does not include...

A) disk name

B) directory name

B) team

21.The state of the operating system in which it stops producing results and responding to requests. - This ..

A) turning off the printer

B) looping

B) turning off the monitor

D) freezing

Doc3.

A) A:\DOC3

B) A:\DOC3\Doc3

IN) A:\DOC3\Doc1

G) A:\TOM3\Doc3

24.The application is

25.The application operates under control

A) RAM

B) processor

B) operating system

D) user

26. General purpose applications do not include:

A) graphic editors

B) custom editors

B) sound editors

D) text editors

Test on the topics “Files and file system”,

"Computer Software"

Option 2

1.The file name consists of two parts:

A) addresses of the first sector and file size

B) name and extension

C) file and directory storage areas

D) name and address of the first sector

2.The application operates under control

A) RAM

B) processor

B) operating system

D) user

3. The extension is assigned to the file:

A) the program when it was created

B) processor

B) user

D) operating system

4.The file name can include up to

A) 16 characters

B)254 characters

B) 256 characters

D) 255 characters

5.In order for files to be stored on the disk, the disk must first be:

A) copied

B) formatted

B) deleted

D) difragmented

6.The root directory is

A) first top

B) the lowest

B) the most important

D) the biggest

7.Single-level file system

A) a disk directory is a hierarchical sequence of file names

B) is a system of nested folders

C) when the disk directory is a linear sequence of file names and corresponding initial sectors

D) a disk directory is a geometric sequence of file names

8.The file is:

A) data storage area on disk

B) program or data stored in long-term memory

C) a program or data that has a name and is stored in RAM

D) a program or data that has a name and is stored in long-term memory

9.Path to file

A) starts with the logical name of the disk, then the desired file is written, then a sequence of names of folders nested inside each other

B) begins with a sequence of names of folders nested within each other, the last of which contains the desired file, then the logical name of the disk is written,

B) starts with the last folder in which the desired file is located, then writes the logical name of the drive

D) begins with the logical name of the disk, then a sequence of names of folders nested within each other is written, the last of which contains the desired file

10. Allotted for expansion

A) 4 characters

B) 2 characters

B) 3 characters

D) 5 characters

11.Choose the correct file name

12.Operating system refers to

A) to shell programs

B) to system software

B) to application software

D) applications

13.To organize access to files, the operating system must have information about

A) about the cluster numbers where each file is located

B) about the volume of the disk

D) about the number of files on the disk

14.During the formatting process, the disk is divided into two areas:

A) name and extension

B) storage area and directory

B) RAM and cache memory

D) sectors and tracks

15.Where the currently running program and processed data are stored

A) in external memory

B) in the processor

B) in RAM

D) on the output device

A) ALT+DEL keys

B) CTRL+DEL keys

B) when you turn on the computer

D) DEL key

17. The operating system is:

A) computer technical documentation

B) a set of devices and programs for general use

C) a set of basic computer devices

D) a set of programs that organize the control of the computer and its interaction with the user

18.The name of the logical drive is indicated

A) in numbers

B) letters and numbers

B) in Russian letters

D) in Latin letters

19.The file path does not include...

A) disk name

B) directory name

B) team

20.The state of the operating system in which it stops producing results and responding to requests. - This ..

A) turning off the printer

B) looping

B) turning off the monitor

D) freezing

21.The file name is:

A) operating system

B) processor

C) the program when it was created

D) user

22.Given a directory tree. Specify the full filenameDoc3.

A) A:\DOC3

B) A:\DOC3\Doc3

IN) A:\DOC3\Doc1

G) A:\TOM3\Doc3

23.During the loading process of the operating system, the following occurs:

A) copying operating system files from a floppy disk to a hard disk

B) copying operating system files from a CD to a hard drive

D) copying the contents of RAM to the hard drive.

24. A directory is a place on a disk named and containing

A) List of programs compiled by the user

B) files and other directories

B) only certain files

D) information about files (name, extension, date of last update)

25.The application is

A) a user who solves his application problems

B) a program with which the operating system solves its application problems

C) devices with which the user solves his application problems

D) a program with which the user solves his applied problems

26.General purpose applications do not include:

A) graphic editors

B) custom editors

B) sound editors

D) text editors

Option 1
26; actions By disorganization of functioning systems ... file; macroviruses; scripted; boot. 128. By ... computers, on which it is used software security ... files and deletes from file the body of the virus, returning files...subject) those, behind... 1. The set of computers and software is called Document Components software provision computer are... 1) Monitor and supervisor 2) Processing programs and systems programming automation 3) Operating system And system programming...

Having encountered an incomprehensible phrase, the reader, as a rule, strives to find out its meaning. This article is a brief excursion for the user into the world of the unknown.

General concept of a file

Long-term storage stores all data in the form of files. What is it? A file is a named sequence of bytes, which in turn consist of bits. It has its own name and location address. The first parameter is specified by a person, and the second is set and remembered for a long time by the operating system. The search is carried out by file name, so there is no need for the user to write down its address.

It happens that information cannot be found on computer media. But even an empty file has its own name, which is an important property of the data set recorded on the hard disk. If it is absent, then such a structure cannot be called storage.

File system

Each (floppy, hard or laser disk) can contain a huge amount of it. The file system is designed to store data and organize various directories. In a broad sense, it consists of the totality of all information on the disk, sets of data structures, and a set of system software tools. The root directory consists of 2nd level attachments, which, in turn, include 3rd level folders, etc. A single-level linear system is used for disks with several files, a multi-level hierarchical system for disks with a large number of them. The second is characterized by a tree structure.

Purpose of the file system

It consists in providing a convenient interface for a person when accessing information located on a disk, and realizing the possibility of sharing objects among many people and ongoing processes. This type of structure allows you to achieve maximum results when working with data.

File types

Thanks to certain information, the computer can roughly “understand” what is in the data set and what program can be used to open it. The extension is the few letters or numbers that appear after the period in the standard file name. It defines the data type and the corresponding program. For example, information recorded on a disc with the mp3 extension will open in the player. The program picture is present in the file image. By this icon, an experienced user immediately understands where the specified data type can be applied. The document will only open in a program designed for text. Video files can be played in the player. Information in the form of pictures opens in a graphic editor. There are many different files. Each of them has an icon indicating the corresponding program.

File: file names

Users give the data set on disk symbolic names. Files are identified by them. In this case, system restrictions on both the characters used and the entire length of the phrase must be taken into account. The file name is the name specified above, which can be the same for several data sets. In this case, the sequence of directory identifiers, that is, the address where the information is located, will be different. In some systems, the same object cannot have several names, in others there is no such restriction at all. In the latter case, the data set is given a unique name. This is a numeric identifier used by any operating system program.

File name composition

Any information on a disk contains several elements. What does the file name consist of? In order to understand this, you need to have a sample before your eyes. The file name consists of two interrelated parts: the name and the extension, which determines the data type. It identifies any information on the medium.

Full name

Here's an example:

C:\Music\Holiday\Melody.mp3.

The full file name indicated in the sample is the name consisting of the file itself and the information path. The last item listed is a list of folder IDs that should be opened sequentially to get from the highest level to the data set. The full file name must be specified, starting from the root directory, and contains a list of all dependent attachments of other levels. This name is absolute. It refers to information regarding the root directory, regardless of the current folder. All name elements are separated by a slash (\) character. This character must be specified before the name of the root directory.

Short name

Constraints are the reason this term came into being. In those days, a file could only have 8 characters in its name. A little later, it became possible to put a period after the name and add 3 extension characters.

It looked like this:

Melody.mp3.

Developers began to use name extensions for technical needs. With their help, programs “learned” to recognize the file type. This file name recording scheme was called system 8.3 (after the number of characters in the name and extension, and a period between them). It had a number of disadvantages: the inability to use spaces, punctuation marks, and letters other than the English alphabet. Therefore, creating a meaningful name was very difficult. The short name does not contain a forward slash ( \ ). By this name you can refer to the data in the current directory.

Long name

Previously, when thousands of files were stored on disks, users knew quite well where certain data came from on the media. Currently, it is impossible to monitor the history of incoming information. Therefore, strict restrictions on title length were removed for the data. What does the file name consist of? Now the name can be written in Russian letters, with some punctuation marks and even spaces. The extension is indicated not only by three characters. If the name contains several periods, the file type is indicated after the last punctuation mark.

However, traditions contain great power, which is why long extensions are not found on computers. Three characters are enough for the system to indicate the file type. There may be at least 250 characters, although this certainly seems overkill.

Problem objects

A document with a long title may not be read correctly on another computer. Therefore, when sending data, you should use Latin letters. The Russian alphabet may not be on the recipient’s computer, and instead of phrases, an incomprehensible set of characters will appear. To organize a file storage system on the user's personal computer, any letters are used.

Correct file name

It can consist of any uppercase or lowercase letters, a number, a period, and an underscore. The use of spaces is not prohibited. However, you should not overuse it, and also do not put it at the beginning of the name. You can include other characters in the name, with the exception of reserved characters (>< | ? * / \ : "). Расширение отделяется от названия последней правой точкой. Длина имени ограничивается 255 знаками. На самом деле обычному пользователю хватает 20 символов. Операционная система не различает строчные и прописные буквы в имени файла. Это означает, что сохранить в одном каталоге два элемента с одинаковым названием, написанным в разном регистре, не получится. Так может выглядеть пример совпадающих имен: «Текст.doc» и «ТЕКСТ.doc».

Incorrect file name

In addition to these restrictions, there is a prohibition on using reserved device names.

So, PRN is a printer. COM1-COM4 - devices connected to serial ports 1-4. AUX performs the same function as COM1. LPT1-LPT4 are elements connected to parallel ports 1-4 (printers), CON (consol) for input - keyboard, output - screen, NUL - “empty” device. When the user tries to specify a reserved name, the system displays an error. A warning is also displayed when prohibited characters are used. It indicates an invalid file name. Incorrectly recorded information about a data set is not saved, but takes on the previous value.

File name template

Operating system shells, as well as various programming languages, allow the user to search names and directories for specific groups. All files are checked for compliance with a given template, if any of them matches the standard, then it is taken into account, if not, it is skipped.

Why is such a sample needed? Often you need to perform the same action on a whole group of files. This takes less time than accessing each document individually. The file name template allows you to select a group that meets specified requirements from the crowd. It is even used in data retrieval.

Special characters

The file name template is specified using special characters:

• An asterisk is a symbol for any group of characters. Their number doesn't matter. For example, one star is a template that matches all the information in the catalog. Thanks to the *.mp3 command, you can change any file of the same type. Filenames starting with my and ending with .txt are highlighted using the pattern my*.txt. The *2014* pattern defines all objects existing on the computer whose names contain the character group 2014.
• is a designation for any single character. For example, for the sample music.??? data starting with the specified word and having an extension of three English letters is suitable. In the na?e.txt template, any symbol can be used instead of the standard question mark.

Other teams

There are also other rules for compiling samples. By including square brackets () in the command with a list of possible values, you can make the search more flexible. If you want to find any files starting with the letter t, without taking into account case, then the pattern should be written like this: *. When searching for data with alphabetical names, you can create a range. A similar template looks like this: ?.jpg. The system will find files with the specified extension type, whose names consist of two characters. Moreover, the first letter k, l, y or z is case insensitive.

Shell meaning

Several special characters can be used in one pattern. Templates are combined with many commands: browsing directories, copying files, searching, etc. However, actions are performed not with the template, but with the data that matches it. The required objects are selected by the command shell.

Pattern expansion is the process of replacing the * character with a consistent sequence of file names.

Some commands will never be able to find a special character in their list of parameters. So what is responsible for data retrieval? The command shell performs the necessary expansion of the pattern in such a way that all file names matching the pattern will be listed.

File name masks

They are used in group operations with data. The mask is a sequence of characters allowed in file names, which may also contain a question mark and an asterisk. With its help, you can delete any temporary file on your computer. The file names in the command can contain different symbols. A question mark marks one arbitrary character, while an asterisk marks an entire sequence. For example, using the command rm *mp3, you can delete all files ending with this fragment. If you need to erase all data in a directory, you should use the rm * command. The command works almost the same way with changing one character. Name masks can also be used with directories.

Problematic copying

The transition to long names creates compatibility problems with previously created programs that use small phrases. In order for applications to open information in accordance with the previously adopted storage structure, the file system must be able to provide unique short aliases for data that has complex names. Newer operating systems support long names. But sometimes the user encounters unexpected problems. Copying files with long names can be difficult.

In this case, even creating a shortcut will not help. Typically, the user only needs to rename the file and try again. Alternatively, you can archive the data, copy and unpack. But what should you do if in the hundredth subdirectory in which the required file is located, the file names are so long because of the path written in them?

Backup options

If the above methods do not work, you should simply connect the network drive by right-clicking on the computer image and selecting the connection from the menu that appears. In this case, you must specify the letter for the desired media and the file path.

As a last resort, the user can use the FAR 2.0 long name copying program and even disable Recycle Bin.

A file can be a file length, and actually creating a file consists of giving it a name and registering it in the file system - this is one of the functions of the operating system. Even when we create a file while working in some application program, in the general case, operating system tools are used for this operation.

According to the methods of naming files, a distinction is made between “short” and “long” names. Before the operating system Windows 95 common way of naming files on computers IBM PC had 8.3 agreement. According to this agreement, adopted in MS-DOS the file name consists of two parts: the actual name and name extension. The file name is allocated 8 characters, and its extension - 3 characters. The name is separated from the extension by a dot. Both the name and the extension can only include alphanumeric characters of the Latin alphabet.

Agreement 8.3 is not a standard, and therefore in some cases deviations from the correct form of recording are allowed by both the operating system and its applications. So, for example, in most cases the system “does not object” to the use of some special characters (exclamation mark, underscore, hyphen, tilde, etc.), and some versions MS-DOS even allow the use of Russian and other alphabets in file names. Today file names written according to agreement 8.3, are considered "short".

The main disadvantage of “short” names is their low content. It is not always possible to express the characteristics of a file in a few characters, therefore, with the advent of the operating system Windows 95 the concept of a “long” name was introduced. This name can contain up to 256 characters. This is quite enough to create meaningful file names.

A “long” name can contain any characters except nine special characters: \/:*?“<>|. Spaces and multiple periods are allowed in the name. The name extension is considered to be all characters coming after the last dot; there can be more than three of them.

The introduction of long names required changes to the organization of file systems based on FAT. The term appeared VFAT, denoting a file system based FAT with support for long names. File system NTFS supports long names from the start.

Along with the “long” name, the operating systems of the family Windows They also create a short file name - it is necessary to be able to work with this file on workstations with outdated operating systems.

Using “long” file names in operating systems of the family Windows has a number of features.

1. If the “long” file name includes spaces, then in service operations it must be enclosed in quotes. It is recommended not to use spaces, but to replace them with underscores.

2. It is not advisable to store files with long names in the root folder of the disk (at the top level of the hierarchical file structure). In FAT-based file systems, the number of storage units in this folder is limited. The longer the names, the fewer files can be placed in the root folder.

3. In addition to the limit on the length of the file name (256 characters), there is a much stricter limit on the length full file name(this includes the file access path, starting from the top of the hierarchical structure). The full name cannot be longer than 260 characters.

4. In long file names, it is allowed to use characters of any alphabets, including Russian, but if a document is being prepared for transmission, it is necessary to agree with the customer (consumer of the document) on the possibility of reproducing files with such names on his equipment.

5. Uppercase and lowercase letters in names are not distinguished by the operating system. However, characters of different cases are displayed by the operating system. If it is desirable to use capital letters for clarity, this can be done.

A file name extension is a sequence of characters used to identify the type of file. The extension is separated by a dot from the file name and usually consists of three, less often four, characters. In early operating systems, file extensions indicating their type were rarely used. Essentially, operating systems MS-DOS only .BAT extensions were analyzed (batch files With teams MS-DOS),.EXE, .COM (executable program files) and .SYS (system configuration files). In modern operating systems, any file name extension can carry information for the operating system.

Usually the name extension is an abbreviation of English words describing the file type: DOC files, TXT files.

Examples of file name extensions:

DOC (English, document) - a document with text formatting, in particular those created by WordPad or Word;

TXT - plain text files (in the so-called ASCII encoding), in which the font and paragraphs have the same appearance, are not formatted, and there are no pictures; in particular, these are files created by the Notepad program;

EXE - program file (from English, executable - “executable”). Operating system when trying to delete a file with the extension exe warns that the file is a program, and without it, not everything will work;

MP3, WAV - sound files;

AVI - audio and video files;

TTF, FON - font files;

ZIP , RAR - compressed archive files;

1NI - configuration (initialization) file for a specific program;

HTM, HTML files of Internet web pages;

GIF, JPG, BMP, TIFF - graphic files with pictures;

Operating systems family Windows have facilities for registering the properties of file types by their name extension, so in many cases the choice of file name extension is not a private matter for the user.

The operating system stores file extension associations in a list that is updated after installing a new program that works with files of a specific type. For example, the .doc extension means: open a document using Word or, if Word is not installed, using WordPad.

Windows applications usually offer to select only the main part of the name and specify the file type, and the corresponding name extension is assigned automatically.