File attributes. Storing information objects of various types on various digital media

Without fail, users save various folders and files on each personal computer and other devices. In the future, there is a need to view information about each such saved document.

To do this, you need to provide access to metadata. There are special file attributes, which are special system information that will help reveal the properties of a particular file. It will also be possible to get detailed information about the entire folder.

Attributes can mean a variety of information. So users can also find out some additional parameters. This applies to data types, the date of creation of files and some adjustments made to it.

Tailored meta information will reveal more data about each specific file. That is, it will help you learn about EXIF ​​for images, as well as some tags for music. So you can really get a lot of valuable information.

However, many users do not pay attention to file attributes at all. But this happens exactly until the need arises to make a change to an open text file, and this simply cannot be done.

Difficulties may also arise for other reasons. Sometimes data from a flash drive or other storage device may simply disappear. But what to do in this case? It is best to clarify in advance what file attributes represent, why they are needed, and so on.

General information. File Attribute Classification

When working with the Windows operating system, users can note the division into four types. These are the main types that users have to deal with. So it’s time to get acquainted with these attributes that any files and partially folders can have.

There is a certain category of data that involves working with system files. This type is known as "S". This attribute usually marks system folders with documents, programs and other important objects that it is best for users not to interfere with.

For this reason, users will not be able to see these objects in Explorer. So you will have to provide access to them only after disabling the option that is aimed at hiding protected system files.

After its activation, you will be able to see all objects. But it’s better not to do this, so as not to cause damage to the processes responsible for the operation of the operating system, as well as many other important components on which the functioning of the device depends.

This is used to prohibit editing text files. If the user often works with information and then saves it to removable storage devices, then in this case you can simply protect the flash drive from writing. You will first need to create a read-only folder in the root of this drive.

This is a good option for protection from third-party users. However, various viruses and other threats “know how” to bypass these barriers in order to penetrate files and simply infect them. So, if necessary, it is best to frequently check this drive to identify various threats.

Now you can consider another option - archival. Users may see an “A” designation. The need to use this type of attributes is to create backups. So it is needed for certain utilities.

It is also useful for recognizing those files that were previously included in the backup. It is also possible to identify those objects that were previously corrected, but are now simply subject to replacement.

Now you can study another type - H. These are hidden attributes that help make objects invisible, but they will not be marked as system attributes. Users can thus try to hide any files and folders so that they are not displayed in Explorer in the future.

But this classification is known to users who worked with previous versions of this operating system. The final versions of this platform have some additional objects.

They do not need to be changed at all, but users should still find out as much information as possible about them. This is an encrypted, compressed attribute, and is also represented by indexed, temporary and others.

In addition to this, there is an option to carry out work with the integrity attribute and carry out work without preliminary cleaning. So the variety of such elements is quite large. The user can see some of the listed components in the file properties section.

Also, even file timestamps can be classified as attributes. They help to find out exactly when the document was created, the time it was first opened and some changes. Thanks to such accurate information, the user can understand exactly how work was done with a certain object.

In the system files, users can usually see only the date of the adjustments made. To access more complete information, you need to open the properties item. In this case, you can see the creation dates of the object and the changes made to it.

In this case, you can correct all this data. If the user makes edits, all these changes will immediately take effect. As a result, the adjustment date will be changed automatically.

Working with attributes. Making various types of edits

Absolutely every user will want to make adjustments to the properties of files. This can be done using standard tools. Third-party assistants can also be used for these purposes.

These programs include a variety of file managers. These types of applications are installed on the vast majority of personal computers. So users will not even need to install this type of assistant.

However, if the user has not downloaded the manager, then in this case it will be necessary to install it. The most striking example of the quality of stable work is Total Commander.

This software product is aimed at providing real assistance when working with files of different types. The utility will display all those objects that can only be in the gadget’s memory. At the same time, it will be possible to learn a lot of different information about each such object that can be useful.

It's very easy to go to the View menu, which manages to provide access even to hidden objects. That is, the user just needs to activate the option with advanced settings. Next, go to the tab in which you can view hidden and system files.

As soon as absolutely all elements become visible, the user can work with them. If suddenly you need to change the attributes for some of them, then to do this you just need to enter the menu called “File”. Next, select the option to change attributes. Total Commander will do all this successfully.

At this moment, a new window will appear in which you can perform all further manipulations. The adjustment process involves the use of numerous parameters of the standard ATTRIB command. It's also easy to make changes to the file modification timestamp.

Even if some functions cannot be performed, you can connect a variety of additional modules to do this. There are several current plugins available online that you can work with.

You can also try working with another software - Free Commander. This utility already contains several important components that competing services do not have. So users can easily do without plugins, using only built-in tools.

There are also several highly specialized programs that are also aimed at working with files, but with more “modest” functionality. An example of a quality application is BulkFileChanger.

So you don’t need to limit yourself to one utility option. Currently, computer technology is developing so quickly that users can easily download a variety of software that will help in solving any problems.

Task No. 4. Answer the questions:

Laboratory work No. 10

Topic: Searching for information on state educational portals

Task No. 1.

1. Download the Internet.

2. Using the search bar, find a directory of links to government educational portals.

3. Write down the email addresses of six state educational portals and give them a brief description. Present it in the form of a table:

Task No. 2.

1. Open Enternet Explorer.

2. Download the Promt electronic dictionary page – www.ver-dict.ru.

3. From the drop-down list, select Russian-English dictionary (Russian-German) .

4. In the text field Word to translate: enter the word you need to translate.

5. Click on the button Find .

6. Enter the result in the following table:

Task No. 3.

1. Download the electronic dictionary page – www.efremova.info.

2. In the text field Dictionary search: Enter the word whose lexical meaning you need to know.

3. Click the button Search . Wait for the search result.

4. Enter the result in the following table:

Task No. 4. Using one of the search engines, find the information and enter it into the table:

Task No. 5. Fill out the table using the Yandex search engine: www.yandex.ru.

Task No. 7. Answer the questions:

Good day, dear user, in this article we will talk about such a topic as files. Namely, we will look at: File management, file types, file structure, file attributes.

File system

One of the main tasks of the OS is to provide convenience to the user when working with data stored on disks. To do this, the OS replaces the physical structure of the stored data with some user-friendly logical model, which is implemented in the form of a directory tree displayed on the screen by utilities such as Norton Commander, Far Manager or Windows Explorer. The basic element of this model is file, which is the same as file system in general, can be characterized by both logical and physical structure.

File management

File– a named area of ​​external memory intended for reading and writing data.

Files are stored in power-independent memory. An exception is an electronic disk, when a structure that imitates a file system is created in the OP.

File system(FS) is an OS component that provides organization for the creation, storage and access to named data sets - files.

The file system includes: The file system includes:

• The collection of all files on the disk.
• Sets of data structures used to manage files (file directories, file descriptors, free and used disk space allocation tables).
• A set of system software tools that implement various operations on files: creation, destruction, reading, writing, naming, searching.

The problems solved by the FS depend on the way the computing process is organized as a whole. The simplest type is a file system in single-user and single-program operating systems. The main functions in such a FS are aimed at solving the following tasks:

• Naming files.
• Software interface for applications.
• Mapping the logical file system model onto the physical organization of the data warehouse.
• FS resistance to power failures, hardware and software errors.

FS tasks become more complicated in single-user multitasking operating systems, which are designed for the work of one user, but make it possible to run several processes simultaneously. To the tasks listed above, a new task is added - shared access to a file from several processes.

The file in this case is a shared resource, which means the FS must solve the whole range of problems associated with such resources. In particular: there must be means for blocking a file and its parts, reconciling copies, preventing races, and eliminating deadlocks. In multi-user systems, another task appears: Protecting the files of one user from unauthorized access by another user.

The functions of the FS, which operates as part of a network OS, become even more complex; it needs to organize protection files one user from unauthorized access of another user.

Main purpose file system and corresponding to it file management systems– organization of convenient management of files organized as files: instead of low-level access to data indicating the specific physical addresses of the record we need, logical access is used indicating the file name and record in it.

The terms “file system” and “file management system” must be distinguished: the file system defines, first of all, the principles of access to data organized as files. And the term “file management system” should be used in relation to a specific implementation of the file system, i.e. This is a set of software modules that provide work with files in a specific OS.

Example

The FAT (file allocation table) file system has many implementations as a file management system

• The system developed for the first PCs was simply called FAT (now called simply FAT-12). It was designed to work with floppy disks, and for some time it was used to work with hard drives.
• Then it was improved to work with larger hard drives, and this new implementation was called FAT-16. this name is also used in relation to the SUF of MS-DOS itself.
• The implementation of SUF for OS/2 is called super-FAT (the main difference is the ability to support extended attributes for each file).
• There is a version of SUF for Windows 9x/NT, etc. (FAT-32).

File types

Regular files: contain information of an arbitrary nature that is entered into them by the user or that is generated as a result of the operation of system and user programs. The contents of a regular file are determined by the application that works with it.

Regular files can be of two types:

1. Software(executable) – are programs written in the OS command language and perform some system functions (have extensions .exe, .com, .bat).
2. Data files– all other types of files: text and graphic documents, spreadsheets, databases, etc.

Catalogs- this is, on the one hand, a group of files combined by the user based on certain considerations (for example, files containing game programs, or files that make up one software package), and on the other hand, this is a special type of files that contain system help information about a set of files grouped by users according to some informal criteria (file type, location on disk, access rights, date of creation and modification).

Special files– these are dummy files associated with input/output devices, which are used to unify the mechanism for accessing files and external devices. Special files allow the user to perform I/O operations using normal file write or file read commands. These commands are processed first by FS programs, and then at some stage of the request execution they are converted by the OS into control commands for the corresponding device (PRN, LPT1 - for the printer port (symbolic names, for the OS - these are files), CON - for the keyboard).

Example. Copy con text1 (work with the keyboard).

File structure

File structure– the entire set of files on the disk and the relationships between them (the order in which files are stored on the disk).

Types of file structures:

• simple, or single-level: A directory is a linear sequence of files.
• hierarchical or multi-level: A directory itself can be part of another directory and contain many files and subdirectories within it. The hierarchical structure can be of two types: “Tree” and “Network”. Directories form a “Tree” if the file is allowed to be included in only one directory (OS MS-DOS, Windows) and “Network” - if the file can be included in several directories at once (UNIX).
• The file structure can be represented as a graph describing the hierarchy of directories and files:

File name types

Files are identified by names. Users give files symbolic names, this takes into account OS restrictions on both the characters used and the length of the name. In early file systems these boundaries were quite narrow. So in popular FAT file system The length of names is limited by the well-known 8.3 scheme (8 characters - the name itself, 3 characters - the name extension), and in UNIX System V 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 specifies in its NTFS file system that a file name can be up to 255 characters long, not counting the terminating null character.

Moving to long names creates a compatibility issue with previously created applications that use short names. In order for applications to access files according to previously accepted conventions, the file system must be able to provide equivalent short names (aliases) to files that have long names. Thus, one of the important tasks becomes the problem of generating appropriate short names.

Symbolic names can be of three types: simple, compound and relative:

1. Simple name identifies a file within one directory, assigned to files taking into account the symbol nomenclature and name length.
2. Full name is a chain of simple symbolic names of all directories through which the path from the root to a given file, disk name, file name passes. So the full name is composite, in which simple names are separated from each other by a separator accepted in the OS.
3. The file can also be identified relative name. The relative file name is determined through the concept of "current directory". At any given time, one of the directories is current, and this directory is selected by the user himself at the command of the OS. The file system captures the name of the current directory so that it can then use it as a complement to relative names to form the fully qualified file name.

In a tree-like file structure, there is a one-to-one correspondence between a file and its full name - “one file - one full name”. In a network file structure, a file can be included in several directories, which means it can have several full names; The correspondence here is “one file - many full names.”

For file 2.doc, define all three types of name, provided that the current directory is the 2008_year directory.

• Simple name: 2.doc
• Full name: C:\2008_year\Documents\2.doc
• Relative name: Documents\2.doc

File attributes

An important characteristic of a file is its attributes. Attributes– this is information describing the properties of files. Examples of possible file attributes:

• Read-Only attribute;
• Sign “hidden file” (Hidden);
• Sign “system file” (System);
• Sign “archive file” (Archive);
• File type (regular file, directory, special file);
• Owner of the file;
• File Creator;
• Password to access the file;
• Information about permitted file access operations;
• Time of creation, last access and last change;
• Current file size;
• Maximum file size;
• Sign “temporary (remove after process completion)”;
• Blocking sign.

In different types of file systems, different sets of attributes may be used to characterize files (for example, in a single-user OS, the set of attributes will not contain characteristics related to the user and security (the creator of the file, the password for accessing the file, etc.).

The user can access attributes using the facilities provided for this purpose by the file system. Typically, you can read the values ​​of any attributes, but only change some, for example, you can change the access rights of a file, but you cannot change the creation date or the current size of the file.

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:

• file creation.
• file destruction.
• writing to a file.
• opening a file.
• closing the file.
• reading from file.
• file addition.
• search in the file.
• getting file attributes.
• setting new attribute values.
• renaming.
• file execution.
• reading a catalog, etc.

In the most general case access rights can be described by a matrix of access rights, 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:

In some systems, users may be divided into separate categories. For all users of the same category, uniform access rights are defined, for example, in the UNIX system, all users are divided into three categories: the owner of the file, members of its group, and everyone else.

File attributes

File attributes

File attributes are a set of bytes that distinguish a file from many other files. The file attributes are:
- file name and content type;
- date and time of file creation;
- name of the file owner;
- file size;
- file access rights;
- file access method.

See also: File attributes Files

Finam Financial Dictionary.

See what “File Attributes” are in other dictionaries:

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 ...

Format is a 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 control parameters- 3.10 file control parameters: Logical, structural and security attributes of the file. Source … Dictionary-reference book of terms of normative and technical documentation

- the (natural) person who created the file or directory. The owner of the file is indicated in the file or directory attribute of the same name. In English: File owner Synonyms: Directory owner See also: File attributes Financial Dictionary Finam... Financial Dictionary

The day, month and year of creation of a specific file. When editing a file, its creation date changes to the current one. See also: File attributes Finam Financial Dictionary... Financial Dictionary

A sequence of characters used to identify the file type. Typically, the extension consists of no more than three characters, separated by a dot from the file name. See also: File attributes Finam Financial Dictionary... Financial Dictionary

In multi-user operating systems, the ability for more than one user to simultaneously access a file with the shareable attribute. The attribute is assigned to the file by the system administrator. In English: File sharing Synonyms... Financial Dictionary

file label- A control record at the beginning of a file containing attributes that are used to identify it. [Hypertext encyclopedic dictionary of computer science by E. Jakubaitis] Topics of information technology in general EN ... Technical Translator's Guide

file transfer- — file transfer Defines the exchange of large blocks of data, such as programs. Figure 3 shows an overview of the ACSI service conceptual model. [GOST R IEC 61850 7 ... Technical Translator's Guide

- (English File Allocation Table “file allocation table”) is a classic file system architecture, which, due to its simplicity, is still widely used for flash drives. In the recent past it was used in floppy disks, on ... ... Wikipedia

Topic: Creating a data archive. Extracting data from the archive. File attributes and size

How does information compression occur?

Data compression is similar to the production of milk powder or dried fruits. That is, it is a process of removing water, which can then be added to restore the product to its original form.

What kind of water could be in the data? This is informational water. There are many repetitions in the data. This can be used to compress data.

For example, compression of text files goes something like this. A table of words and expressions found in the text is compiled. All words and expressions in this table are then given numbers. And all the text in the file is replaced with numbers from the table of words and expressions. This method allows you to reduce the size of a text file by 2-3 times. Sometimes the text is compressed 10 times if it contains a lot of repetitions.

A program that converts a text file into a “compressed” form is called a packer. And the resulting file is called a packed or compressed file.

Very often, compressed files are called archives or archive files, which, strictly speaking, is incorrect. Initially, archives were files specifically created during backup processes. This process created one file that contained several source files and folders. This was the archive. No compression was performed. A similar situation still exists in the Linux operating system, where data archiving and data compression are two independent processes. In the MS-DOS operating system, and then in MS Windows, data compression programs from their very first versions began to support both compression and archiving of data, that is, they created a compressed file containing not one, but several source (archived) files and folders . Since then, in these operating systems, the concept of “archiving” means both archiving (collection into one archive file) and simultaneous data compression.

Since the archive file is not written in text format, text editors cannot work with it. Before opening an archived file with a text editor, the file must be unzipped. Unzipping is performed by the same program - the archiver. After unzipping, the text file takes on exactly the same appearance and size as before archiving.

Text archivers can also archive program files. Only programs are much less compressed than text.

Packers used to compress text and programs cannot effectively compress audio, image or video files. Other, more complex algorithms have been developed to compress them. True, after unpacking, the resulting files differ slightly from the originals (this compression is called lossy compression). But this is not captured by the ordinary human ear and is not noticed by the ordinary eye on the monitor screen.

But what about other, non-text data?

Let's look at graphic files. Unarchived graphics are a drawing consisting of many multi-colored dots. In this format, a color is specified for each point in a drawing or photograph. The graphic file of such a drawing has the extension “BMP”. But such files are quite large in size. Even a small photo in BMP format will be several megabytes in size. That is, it will not fit on a floppy disk, and it will not be easy to transfer it over the Internet.

To reduce the size of a graphic file, it is compressed using special mathematical methods. Thus, the graphic file can be reduced in size by 20-30 times. A compressed graphic file cannot be fully recovered. When printed on a good printer, there will be a noticeable deterioration in the quality of the drawing. But this will not be visible on the monitor screen.

The most common image compression formats are “GIF” and “JPEG” (or “JPG”). Such graphic file formats can be created, for example, by the graphic editor “PhotoShop” or the already familiar “FineRider”. The deeper the image is compressed, the more quality it loses.

Much later, effective methods of audio compression appeared. If you go to a regular music CD, you will find files with the extension “CDA”. These files contain uncompressed digital audio. Such files are very large. A CD contains 80 minutes of unarchived music. Compression of sound files required special research into human hearing. It turned out that some sounds can be removed from the sound file, and this will be imperceptible to human hearing.

The most common compressed audio format is "MPEG3" (or "MP3"). It is created by specialized sound editors and transcoding programs from other sound formats. Playing compressed audio files in MP3 format on a computer requires a processor power of at least 100 megahertz. You can compress an audio file tens of times. But with high compression, sound quality begins to be irretrievably lost.

The video combines sound and graphics. In addition to sound, this is another 24 frames for every second. This explains the huge size of video files and the need to compress them.

When CDs first appeared, a feature film could not fit on one disc. This problem was solved by the compressed format “MPEG4”. Displaying compressed video further increases the demands on processor power. 200 megahertz is no longer enough to play MPEG4.

Archiving(packaging) - placing (downloading) source files into an archive file in compressed or uncompressed form.

Archiving is intended to create backup copies of used files in case the main copy is lost or damaged for any reason (user carelessness, magnetic disk damage, virus infection, etc.).

For archiving, special programs are used, archivers that carry out packaging and make it possible to reduce the size of the archive, compared to the original, by approximately two or more times.

Archivers allow you to protect the archives they create with a password, save and restore the structure of subdirectories, and write a large archive file to several disks (multi-volume archive).

Either one or several files can be compressed, which in compressed form are placed in a so-called archive file or archive. Large programs distributed on floppy disks are also located on them in the form of archives.

Archive file- this is a specially organized file containing one or more files in compressed or uncompressed form and service information about the names of the files, the date and time of their creation or modification.

The gain in archive size is achieved by replacing frequently occurring code sequences in the file with links to the first detected sequence and using information compression algorithms.

The degree of compression depends on the program used, the compression method, and the type of source file. The most well-compressed files are graphic images, text files and data files, for which the compression ratio can reach 5 - 40%; files of executable programs and load modules are compressed less - 60 - 90%. Archive files are almost not compressed. Archiving programs differ in the compression methods they use, which consequently affects the compression ratio.

In order to use the information packed in the archive, you need to open or unpack the archive. This is done either by the same archiver program or by a paired unarchiver program.

Unzipping(unpacking) - the process of restoring files from an archive in their original form. When unpacking, files are extracted from the archive and placed on disk or in RAM.

Self-extracting archive file is a bootable, executable module that is capable of independently unzipping the files contained in it without using an archiver program.

The self-extracting archive is called SFX archive (SelF-eXtracting). Archives of this type are usually created in the form of an .EXE file.

Archivers used to compress and store information provide the representation of one or more files in a single archive file, each of which can be retrieved in its original form if necessary. IN table of contents of the archive file For each file it contains, the following information is stored:

file name;

information about the directory in which the file is contained;

date and time of the last modification of the file;

file size on disk and in archive;

A round-robin code for each file used to check the integrity of the archive.

Archivers have the following functionality :

Reducing the required amount of memory for storing files from 20% to 90% of the original volume.

Updating in the archive only those files that have changed since they were last added to the archive, i.e. The packer program itself monitors changes made by the user to the archived files and places only new and changed files in the archive.

Combining a group of files while storing directory names with file names in the archive, which allows you to restore the full structure of directories and files when unzipping.

Writing comments on the archive and files in the archive.

Creating self-extracting archives that do not require the archiver itself to extract files.

Creation of multi-volume archives – sequences of archive files. Multi-volume archives are designed for archiving large sets of files onto floppy disks.