A file as a unit of information storage on a computer attributes. File management, file types, file system, file attributes

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 complex 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 determines, 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:

Software(executable) – are programs written in the OS command language and perform some system functions (have extensions .exe, .com, .bat).
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 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 (working 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:

Simple name identifies a file within one directory, assigned to files taking into account the symbol nomenclature and name length.
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.
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.

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 detected 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. To play MPEG4, 200 megahertz is no longer enough.

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.

Splitting a single file name into its own name and extension exists in almost all operating systems that use the concept of file and file system. This concept was introduced so that the file name could immediately determine its purpose: homogeneous documents had the same name extension, and heterogeneous ones had different ones. This system continues to be used today.

How does the operating system know which program to use to open a document?

In the Windows XP operating system, the file name extension uniquely identifies the document type. The operating system determines the “suitability” of a file for a specific purpose by its name extension. Using an "inappropriate" extension interferes with normal use of double-click and context menus and may result in the file being unavailable in some dialog boxes. In particular, each file name extension is associated with the program used to open the corresponding files.

What is a file type?

Strictly speaking, a file type is the information that appears in the Type column when files are presented in Datasheet view. Since the file type is uniquely determined by the extension of the file name, this extension is often used as the file type and they speak, for example, about EXE files, about .TXT files, and so on. Although the length of a file name extension is not limited to three characters, it is generally accepted to respect this limit; including in order to ensure continuity with earlier operating systems.

What file types do you need to know about?

Immediately after installing the operating system, a large set of file types recognized by the operating system are automatically registered. Thus, files with the .EXE extension are executable program files. Different groups of operating system service files may have extensions .CPL, .DLL, DRV, SYS and others. Unformatted text documents have the extension .TXT, and formatted WordPad and Word documents have the extension .DOC. WindowsXP recognizes a large number of multimedia document formats: graphic (.BMP, .GIF, JPG, etc.), audio (.WAV, .MRE, etc.), video (.AVI, .QT, .MPG, etc.). Internet documents (Web pages) have the extension .HTML or .HTML. In addition, each program installed on a computer usually supports working with a number of specific documents. The corresponding file types are registered when you install this program.

What information is associated with a file type?

The file type is associated with:

Icon corresponding to this file type;

The application used for such files;

Description (name) of the type;

Standard name extension;

A set of actions that can be performed through the context menu, with one of them performed by double-clicking it.

How can I find out what types of files are registered in the system?

By opening the My Computer window or any<: кно папки, дайте команду Сервис >Folder properties. You can also open the Folder Options dialog box using Control Panel. Select the File Types tab. All file types registered by the operating system are listed in the Registered file types list on this tab. By selecting Q;>. any of them, you can see its description in the panel at the bottom 1&&" part of the dialog box.

How to register a new file type?

Having opened the My Computer window or any folder window, give the command Tools > Folder Options and select the Files tab. Now click on the Create button - the Create a new extension dialog box will open. In this window you need to use a new (or already existing) extension, usually of three characters. Click on the More button. A list of Matched file type will appear in the dialog box. If the selected extension is already registered, the existing item is automatically selected in this list. Otherwise, the item is displayed in it.<Новый>. The type name in this case is generated automatically; If you, say, chose the AAA extension, the new file type will be registered as an "AAA" File.

How do I select the program used to open a non-standard file type?

If a file with an unusual extension already exists on your computer, the easiest way is to simply double-click its icon. The operating system will display a dialog box informing you that the file cannot be opened. Select the Select a program from the list manually checkbox and click OK. The Select Program dialog box opens. The program used to open such files can be selected from the Programs list or found using the Browse button. If you select the Use this for all files of this type check box, the operating system will create a registration for the corresponding file type or modify an existing one. In the future, double-clicking on the icon of such a file will automatically launch the selected program. The second way to select a program to open a file is to change the registration of that file type. With the My Computer window or any folder window open, select Tools > Folder Options and select the File Types tab. On this tab, register a new file type or find an existing one in the Registered file types list. Click on the Change button and continue as described above.

How do I change the characteristics of a registered file type?

With the My Computer window or any folder window open, give the Tools Folder Options command and select the File Types tab. On this tab, select an existing file type in the Registered File Types list. Click the Advanced button. In the Edit file type properties window that opens, you can enter a description of this file type (the field at the top of the window) or change the icon assigned to this type (the Change icon button). The remaining controls are used to customize the context menu for a given file type!

How can I change the context menu for a specific file type?

The context menu of a file icon is formed from two main parts. The permanent part of the menu contains commands for copying, moving, deleting and renaming a file;;, as well as for creating a shortcut. The variable part contains commands that are specified when registering a file. If there are no such entries in I or if there is no registration at all), the Open with command is included in the context menu, allowing you to select a program to open the file. To change the set of commands or the action performed when a command is selected, open any folder window or Explorer and select Tools > Folder Options. On the File Types tab, you need to select the file type whose registration data requires changing, and click on the Advanced button - the Change File Type Properties dialog box will open. The commands assigned to this file type are listed in the Actions list. To add a new command, click on the Create button. To change already and m< ющуюся команду, следует выбрать ее в этом списке и щелкнуть на кнопке Изменить. В открывшемся диалоговом окне можно изменить имя операции, а также сформировать команду, соответствующую данному пункту контекстного меню. Команда обычно включает в себя имя запускаемой программы (ее можно выбрать кнопкой Обзор), дополнительные параметры и имя используемого значка, для задания которого указывается специальный параметр в виде «%1».

How do I select a command to execute when double-clicked?

The command that is executed one by one;>] i

Clicking the icon is also one of the possible actions and is considered the default action. When you open the context menu, this command is highlighted in bold. To take the appropriate action, you must open the Change File Type Properties dialog box corresponding to the desired file type (Shrimer, My Computer > Tools > Folder Options > File Types > Change). Having selected the operation that should be performed by double-clicking in the Actions list, click on the Default button.

How to unregister a file?

If the file type was registered and a program was installed, then deregistration is usually carried out automatically when the program is uninstalled. Refusing to use a certain type of file is usually also a good substitute for deregistering it. Thus, this operation is interesting, as a rule, only when “accidentally” registering a file type and assigning an inappropriate program to it. To unregister a file type, open the Folder Options dialog box (for example, My Computer > Tools > Folder Options t File Types), select the desired file type, and click the Delete button.

What information is contained in the file properties dialog box?

The context menu of any file icon contains the Properties item. When you select this command, the properties dialog box for this file opens, containing one tab - General. An additional Shortcut tab appears if you used a shortcut rather than an icon. The General tab contains the same data that can be seen in the folder window in Table mode, but presented in more detail. The top bar shows the file type and the application that is typically used to open such files. Below is the folder where the file is located and details about the size of the file (including the disk space it occupies). The bottom panel shows the dates the file was created, modified, and opened. At the very bottom of the dialog box are the file attributes, and these are the only parameters that can be changed in this case. Use the Shortcut tab to change the options used when opening a file (or launching a program) using a shortcut. Here you can view or change the “command line” (Object field), which is usually the search path for the object, specify which folder should be the current one when working, and select the initial window size. For particularly frequently used documents and programs, you can select a keyboard shortcut that allows you to use this shortcut at any time and even without using the mouse (Shortcut field). The Change Icon button allows you to change the image used by this shortcut. The Find Item button allows you to quickly open the folder window that contains the file associated with this shortcut. Program icons and shortcuts also display a Compatibility tab, making it easier to run applications designed for older operating systems on Windows XP.

What are file attributes?

File attributes are additional information related to a given file and stored in a folder. Historically, attributes were introduced in the earliest versions of the MS-DOS operating system. There are four attributes: Read Only (R), Archive (A), Hidden (H) and System (S), the state of which can be changed (enabled/disabled) in the properties dialog box for this file.

How to enable display of file attributes in table view?

To constantly monitor the attributes of files, you can enable their display in table view in Windows > folders and in Explorer. To do this, open the desired folder, set its viewing mode as a table (View v Table), right-click on the column headers and select Attributes in the context menu that opens. This menu checkbox typically only affects windows whose setting has been explicitly changed. In the additional column of the table, included attributes are marked with capital letters A, S, H, R.

What does the Read Only attribute mean?

The Read Only attribute indicates that the file cannot be modified. If this attribute is enabled, then “sta!” Standard attempts by the operating system to change, delete or rename a file will fail. This attribute, in particular for ee ki machines, is enabled for all files recorded on the CD.

What does the Hidden attribute mean?

The Hidden attribute specifies that the file should not be displayed in the normal folder window. This attribute is intended to protect important files from unintentional or malicious destruction or damage. However, the Windows XP operating system allows you to enable the display mode of such files if the user deems it necessary (My Computer > Tools > Folder Options » View > Show hidden files and folders).

What does the Archive attribute mean?

The Archive attribute can be USED by backup programs to indicate that the file has been modified. "Regular" programs that modify the contents of a file turn this attribute on, but backup programs themselves turn it off. Thus, if this attribute is enabled, then the file has been recently modified and requires a backup. This system is rarely used these days, so the Archive attribute doesn't make much sense. For the reasons stated above, it is enabled for almost all files, but disabling it makes no sense.

What does the System attribute mean?

The System attribute combines the properties of the Read Only and Hidden attributes, while simultaneously indicating the special importance of the file equipped with such an attribute. The Windows XP operating system does not allow you to independently enable or disable this attribute. However, if the display of system files is enabled (on the View tab of the Folder Options window, the Show hidden files and folders checkbox is selected and the Hide protected system files checkbox is cleared), attempting to delete or rename a system file or folder will only result in a confirmation request to perform this operation.

Task No. 4. Answer the questions:

1. What is archiving?	This is the compression of one or more files in order to save memory and placing the compressed data in a single archive file.
2. What is the purpose of archiving?	This is compression, compaction, packaging of information for the purpose of its most optimal placement on external media (disk or floppy disk).
3. Which file is called an archive file?	an organized file containing one or more files in compressed or uncompressed form and service information about file names, date and time of their creation or modification, sizes, etc.
4. What is unzipping?	meaning the reverse process of archiving, i.e. the process of restoring records of compressed, archived files or their copies for use in work.
5. What information is stored in the table of contents of the archive file?	name, type, date and time of last modification, size per disk
6. What functionality do archivers have?	Archiving data, unarchiving a previously created archive, creating self-extracting and multi-volume archives, using encryption algorithms

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:

№	Portal name	Portal email address	Portal characteristics
	Federal Service for Supervision in Education and Science	http://www.obrnadzor.gov.ru	General information about the service: regulations on the Federal Service, information about management and structure, telephone directory. Collection of official documents. Informational resources. Coverage of competitions in the interests of Rosobrnadzor. Official materials of the service for quality control of education (USE), supervision of compliance with legislation, licensing, certification and accreditation, certification of scientific and teaching personnel and state certification of schoolchildren. News and announcements.
	Education: national project	http://www.rost.ru/projects/education/education_main.shtml	General information about the project: goals and objectives, main activities, expected results. Coverage of ongoing projects and programs in the field of secondary, higher and vocational education. Collection of documents. Project news.
	Information and communication technologies in education	http://ict.edu.ru/	Electronic library: books, articles on the problem of information technology in education. Information about the forums, about the conferences. Resource catalogue. A database of organizations whose activities are related to education in the field of information and communication technologies and the use of ICT in education.
	Russian Open Education Portal	http://www.openet.edu.ru/	Materials of the Central Server of the Consulting Center for the Information and Educational Environment of Open Education. Information about the software complex "Russian Open Education Portal": concept, regulatory support, recommendations, glossary. An integral catalog of virtual universities and representative offices, as well as information about courses, disciplines, specialties and directions, a collection of curricula. Education news. Press review and information and analytical materials in the field of education. Electronic versions of scientific and educational publications. Educational network conferences and forums.
	Science and education:	http://edu.rin.ru	Materials about education in Russia. Catalogs of educational institutions at various levels and educational authorities: preschool education, school education, vocational education, higher education, research activities, advanced training, distance education, Internet training. Abstracts, articles, dictionaries, programs
	Interneturok.ru: a collection of video lessons on the main subjects of the school curriculum	http://www.interneturok.ru	Video lessons on basic school subjects, materials on psychology for parents and teachers.

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:

Word	Lexical meaning
Metonymy	1. A figure of speech representing the replacement of the name of a phenomenon, concept or object with the name of another object, inextricably linked in our minds with the idea of such a phenomenon (“table” instead of “food”); using a similar figure of speech
Video card	an electronic device that converts a graphic image stored as the contents of computer memory into a form suitable for further display on a monitor screen.
Iron	A chemical element, a hard, malleable, silver-colored metal that combines with carbon to form steel and cast iron. decomposition Mild steel.
Papyrus	A scroll made from glued strips of the stem of such a plant as a material for writing among the Egyptians and other ancient peoples.
Scalpel	A small metal surgical knife.
Debit	Income, the total amount of cash receipts.

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:

Routing

(consolidation of knowledge and development of skills/ practical training/ laboratory work)

MDK/Discipline

OUDp. 12 Computer Science

Group

F-11,12,13

Lesson topic

A file is a unit of information storage on a computer. (Ex.10)

Type of activity

Practical work

Purpose of the lesson

Get an idea of archiving files, become familiar with the concept of redundancy, learn how to archive and unpack files, and gain the basic concepts necessary for competent work on a computer.

Lesson objectives

Educational: studying the principles of file archiving; studying the functions and operating modes of the most common archivers; acquiring practical skills in creating archival files; acquiring practical skills in extracting files from archives

Educational: promote the formation of logical thinking

Educational: cultivate a sense of responsibility.

Hardware and software

Software requirements:

operating systemWindows XP

MS Office

Means of education

Multimedia presentation, demonstration material

Methods and techniques

Group discussions, brainstorming, verbal - visual

Pedagogical technologies used

Information computer technologies

Organizational structure of the lesson

Stage 1

Organizing time

Purpose of the stage

Preliminary organization of the group (checking absentees, the external condition of the premises, workplaces, the presence of attendants, working posture and appearance of students, organizing attention)

Duration of the stage

3 minutes

Stage 2

Updating knowledge

Purpose of the stage

Reproduction of knowledge and skills by students

Duration of the stage

10 minutes

Frontal

Coordinator, organizer,thought-provoking

Contents of the stage

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).

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.

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) is 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.

A 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.The table of contents of an archive file contains the following information for each file it contains:

Archivers have the following functionality:

Development

(fastening PC and OK)

Consolidating knowledge on the topic Creating a data archive. Extracting data from the archive.

Stage 3

Purpose of the stage

Explaining to students how to do practical work

Duration of the stage

3 minutes

Functions of the teacher at this stage

Coordinator, organizer

Contents of the stage

It is necessary to solve problems to find the total area and the area of the lateral surface of the cylinder

Stage 4

Performing various tasks, tasks, exercises

Purpose of the stage

Carrying out practical work, assistance with implementation

Duration of the stage

20 minutes

Form of organization of student activities

Individual

Functions of the teacher at this stage

Organizing, directing, instructing

Contents of the stage

Explore the theoretical rationale.

2. Complete practical tasks on the options.

3.Answer test questions as directed by the teacher.

4.Draw up a report.

Contents of the report:

1. Title and goals of the work.

2. Results of completing practical tasks.

3.Answers to security questions.

4. Conclusion.

Option 1

Create a WORK directory and EXE, COM, ZIP, WD and RAR subdirectories according to the scheme.

Copy 5 files with the *.EXE extension to the EXE directory, 4 files with the *.COM extension to the COM directory, and all files from the My Documents directory to the ZIP and RAR directories.

Archive the files in the EXE directory using a ZIP archiver with password 234.

Archive the files in the COM directory using the RAR archiver, adding the comment text “This is my archive.”

In the RAR directory, create a multi-volume archive, 1457664 bytes in size, using the RAR archiver.

Archive files in the ZIP directory, creating a multi-volume archive of 1457664 bytes in size using the RAR archiver;

Copy any archive file to the WD directory and unzip it by deleting the archive file;

Archive the WORK directory using the RAR archiver, taking into account directories and subdirectories.

Type

archiver

ZIP

RAR

Size

catalog

Before archiving

After

archiving

Degree

compression

Before

archiving

After

archiving

Compression ratio

EXE

COM

Option 2

Create a WORK directory and EXE, COM, ZIP, WD and RAR subdirectories.

Copy 5 files with the extension *.COM to the EXE directory, 4 files with the extension *.EXE to the COM directory, and all files from the My Documents directory to the ZIP and RAR directories.

3. Archive the files in the EXE directory using the RAR archiver with password 128.

Archive the files in the COM directory using a ZIP archiver, adding the comment text “This is my archive.”

In the RAR directory, create a multi-volume archive of 1440 KB in size using the RAR archiver.

In the ZIP directory, create a multi-volume archive of 1440 KB in size using the RAR archiver.

Copy any archive file to the WD directory and unzip it by deleting the archive file.

8. Archive the WORK directory using the RAR archiver, taking into account directories and subdirectories.

Create a self-extracting (SFX) archive in the WORK directory of the COM directory.

Enter the data into a table and show the result to the teacher.

Type

archiver

ZIP

RAR

Size

catalog

Before archiving

After

archiving

Degree

compression

Before

archiving

After

archiving

Compression ratio

EXE

COM

The compression ratio is determined as follows: the directory size after archiving is divided by the directory size before archiving and multiplied by 100

Consolidation

PC and OK

Develop skills in creating data archives

Stage 5

Checking the completion of work; discussion of mistakes made and their correction

Purpose of the stage

Check the implementation of practical work

Duration of the stage

3 minutes

Form of organization of student activities

Individual assessments of your comrades.

Functions of the teacher at this stage

Contents of the stage

Students exchange notebooks. The correct answers are highlighted on the slide, students mark the correct answers and give marks to each other.

Consolidation

PC and OK

Develop self-esteem skills and

Stage 6

Reflection (summarizing and self-analysis of activities/feedback)

Purpose of the stage

Assessment of mastery of skills, formation of self-esteem skills

Duration of the stage

3 minutes

Form of organization of student activities

Frontal, individual

Functions of the teacher at this stage

Organizer, analyst, expert

Contents of the stage

So, what did we do in class today?

Have you completed all the practical tasks?

What difficulties did you encounter when completing practical tasks?

1. What is archiving?

2. What are the main actions when working with archives?

3. What archives are called self-extracting?

4. How is the archive encrypted?

5. Which files do not make sense to archive?

6. Why does it make sense to first archive it before sending a text file by email?

Consolidation

PC and OK

To develop the ability for self-analysis in students.

Stage 7

Homework

Purpose of the stage

Consolidation of acquired knowledge

Duration of the stage

3 minutes

Functions of the teacher at this stage

Organizer, expert

Contents of the stage

Completing of the work:

Task No. 1.

Create an Archives folder in your folder. In it, create folders Images and Documents.

Find and copy pictures with *.jpg, *.bmp and *.gif extensions to the Images folder.

Compare the sizes of *.bmp, *.gif. and *.jpg files. and write the data into table_1.

Place *.doc files (at least 3) in the Documents folder and write down their original sizes in table No. 1.