Golovna  /  Hard disks  /  Presentation on the topic of archiving. Presentation - archiving programs and their characteristics

Presentation on the topic of archiving. Presentation - archiving programs and their characteristics

Hard disks
04.12.2023

Archiving is the process of compressing one or more files by saving memory and placing all the data in one archive file.

Data archiving means changing the physical size of the files where the data is stored, without significant information loss.

Archiving is carried out in the following cases:

- it is necessary to create backup copies of important files

- you need to save space on the disk

- it is necessary to transfer files via Email

The main shortcoming archives make it impossible to directly access the data. They must first be taken out of the archive and unpacked.

The unpacking operation, as well as packaging, will require various system resources. This is not a mitt operation. Therefore, archives are mostly stagnant and rarely preserved

Methods of compression of archivers.

Koduvannya dovzhin series(RLE – short run – length encoding – encoding dovzhin series).

A successive series of new data elements are replaced by two characters: the element is repeated. It is widely used as an additional and intermediate method. As an independent method, it is difficult, for example, to use the BMP graphic format.

_________________________________________________________________________

Let’s say, here’s a song fragment from the tributes:

The fragment is careful to follow a pattern. The sequence "110" is repeated several times. This way it is possible to replace a fortune-telling fragment with an offensive sequence:

KEY\repeat\repeat\repeat\

Below the key, the section 110 is indicated, and the repeat symbol means that the same place is responsible for the same key as the one in front. It is reasonable to say that repetition is designated as 1,

then the output fragment is transformed into:

As a result, from a sequence of twelve bits, a sequence of six bits is output. Tobto zastosuvannya

The coding algorithm allowed us to compress the output file into two

Dictionary method (LZ – shorthand for Lempel Ziv – names of authors).

The most advanced method. A dictionary is created that consists of sequences of data or words. When compressed, these words will be replaced with their codes from the dictionary. In the most extensive implementation option, the dictionary is the output data block itself.

The main parameter of the vocabulary method is the size of the vocabulary. The larger the vocabulary, the greater the efficiency. However, for heterogeneous data, the overly large size may be generous, because if the type of data changes suddenly, the dictionary will be filled with irrelevant words. For this compression method to work effectively, additional memory is required. Approximately more than that is required for the output data of the dictionary. A true advantage of the dictionary method

Entropy method(Huffman - Huffman's coding, Arithmetic coding - arithmetic coding)

In this method, data elements that are often shortened are encoded when compressed with a shorter code, and more rare data elements are encoded with a short code. Due to the fact that there are significantly more short codes, the output size is smaller than the output size.

Widely vikorist as an additional method. As an independent method, it is difficult, for example, to use the JPG graphic format.

Context modeling method(CM is shorthand for context modeling).

This entire method will have a model of the output data. When you squeeze the worm element, this model shows its transferability and reliability. Obviously, to ensure completeness, the data element is encoded using the entropy method. The more precise the model is for the output data, the more precise the transfer is, and the shorter the data elements are coded.

For an effective model, a lot of memory is required. When unpacking you will see the same model. Therefore, the flexibility and availability of RAM for packing and unpacking is also possible. Nowadays, contextual modeling methods allow you to remove the highest level of compression, but are limited to extremely low fluidity. PPM (PPM - Prediction by Partial Matching - forecast by

private run).

A type of contextual modeling. Prophecy

is marked on the stand of the singing ring

Method for sorting a block of data(BWT – short for Burrows Wheeler Transform – in the name of the authors).

This is a special kind or group of creations, the basics of sorting. Such a re-creation can be given some kind of tribute. When sorting is done over the blocks, the data are first broken into pieces. The main parameter is the size of the block that is being sorted. To unpack the data, you must follow the same steps as when packing. Therefore, the speed and efficiency of the operative memory may not be the same. Archivists who use this method must show the high speed and level of compression for text data.

Forward conversion and filtration.

These methods do not serve for compression, but for presenting information to the hand for further compression of the appearance.

For example, compressed multimedia data is characterized by smooth changes in the level of the signal. Therefore, delta-reversal stagnates, if the place of absolute value is taken separately.

Create filters for text, formatted files, databases, etc.

Segmentation.

This is first broken into single pieces. Then these parts are coded separately or in groups.

There are obviously a great number of compression methods. The skin method depends on the orientations of one type or group of real data. Good results are shown by comprehensive use of methods.

Features of the data.

The level of compression mainly lies in the output data.

It’s good to squeeze together in front of everything

uncompressed data.

The audio is compressed (WAV), the image is compressed (BMP).

Don’t be squeezed by all the data that has already been squeezed,

for example, archives (ZIP, CAB), typed documents (PDF),

Style graphics and video (JPG, GIF, AVI, MPG), style sound

Archiver programs.

Archivers are a program (a set of programs) that combine the compression and updating of these files at a glance. The process of compressing files is called archiving. The process of updating existing files is unzipping.

Today's archivers vary in algorithms, speed of operation, compression level (WinZip 9.0, WinAce 2.5, PowerArchiver 2003 v.8.70, 7Zip 3.13, WinRAR 3.30, WinRAR 3.70 RU).

Other names of archivers: utilities - packagers, programs - packagers, service programs that allow you to place copies of files in a thin-view archive file.

The trace is separated

- archiver program

- archive format

Squeezing method.

In addition to data compression, modern archivers provide several additional functions.

You can see a few main ones:

- compression of certain files and entire directories;

- The system will self-extract (SFX) archives. Just for unpacking the archive An archiver program is not required;

- change instead of archive;

- encryption instead of the archive;

- Information for updating the archive in case of partial breakdown and possibility

updating old archives;

- dividing the archive into several parts and volumes;

- console version of the program for robots from the command row;


An archiver program is a computer program that allows you to change and save this information without harm. There are different methods of archiving files, which vary by the level of file compression, storage speed and other parameters.


There is a wide variety of archivists. Axis of applications RAR WinRAR (or as they call it “Winrar”, Win-RAR) is one of the most handy and difficult computer archiving programs for the Windows operating system. The names of the programs are listed as WIN (Windows) and RAR (Roshal ARchive). The author of the program is Evgen Roshal, also our spivitch specialist. It has a very small size with a rich set of functions and speed of operation. The current version at the time of writing is winrar Winrar has a special compression algorithm for multimedia files, object libraries and programs that are being compiled. Winrar provides the ability to update corrupted archives, encrypt, create large-volume archives and many other useful and unique functions. ZIP A new version of the program for working with archives in ZIP format has appeared. CoffeeCup Free Zip Wizard 2.6 provides a simple way to create a ZIP archive, as well as unpack and modify other archives in ZIP format. All actions in the program are carried out with the help of detailed masters, which explain the detailed stage of work, which allows you to quickly understand all the details of archiving files. The program can create archives that extract themselves, allows you to adjust the level of file compression and set a password for the archive. Once you have installed the features of CoffeeCup Free Zip Wizard 2.6, you can immediately transfer it to an FTP server after creating the archive. In addition, there is a function to search for ZIP files on any drives connected to the computer.


7 Z Archiver 7-Zip 4.31, which supports work with a wealth of archive formats. 7-Zip has a simple and intuitive interface: you can work in single disk mode, or you can work with archives/files using 2 disk panels (similar to a file manager). The program uses the official format of the created archives 7z. The level of compression in this case is simpler than that of the popular archive formats ZIP and RAR, but the process of archiving files in this format is more troublesome. 7-Zip supports working with available archive formats: 7z, ZIP, CAB, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM and DEB. The ability to create archives to self-unpack has been improved.


The principle of work The principle of work of archivers is based on the search for “excessive” information in the file and further encoded using the method of changing the obligation. When archiving, the file compression stage must be stored in the correct format. Archiving programs can reduce the file size to the minimum possible size. The interface of all current archiving programs is very similar.














File archive Launch the WinRAR 3_0 archiver. See the files (indicate the directory) and activate the “Add” button on the program toolbar. Before creating a new archive, you need to set the archiving parameters: set the name of the archive file; Saving location on disk; Select the archiving format (rar, zip, exe). select one of six archiving methods: without compression - places files in archives without packaging; shvidkisny – filthy squeezes, ale shvidko; shvidky; simple - the backup copy of the data is wasted; garnium; maximum - the best pressure with the least amount of pressure; select the size of the dictionary. Values ​​64,128, 256, 512 more - shorter, or more intense; Select the size of the file on large-volume archives, usually for saving on floppy disks. Rozmir Kb;


It is possible to create a file that self-extracts - SFX mode (SelF-tXtracting). For unzipping, you don’t need a program, you just need to run the file on Windows, the file is downloaded and there is an extension.exe. In the Archive Parameters panel, set: Archive file name; Place the archive on disk (for cleaning); archive format; squeeze method; Dimensions of the dictionary (per umovchannyam); volume size; renewal method; Archiving parameters. To download files (directory), you need to select an archive file and activate “Viluchity” in the program toolbar. After cleaning the archives, unpack them into the same directory



Slide 1

Archive programs Archive file MS DOS archivers PKZIP and ARJ RAR Windows archivers WinRAR 2.5 Capabilities WinRAR WinZip 7.0 The oldest test of the speed code and the level of compression of the most popular archivers (WINRAR, WINZIP, RAR ).
Archiving software and its characteristics

Slide 2

On the menu
Archiving programs
Various retailers have created special programs for archiving files. Some of them are distributed free of charge, some are distributed on a commercial basis (for a fee), and most programs of this kind are widely distributed as “Shareware”. tobto. they can be taken away without cost, but if you want to vikorize them steadily, then you will have to send the guilt to the authors or to all the people in the city. As a rule, programs for archiving files allow you to place copies of files on disk in an archive file, drag files from an archive, view them instead of an archive, etc. Various programs vary in the format of archive files, the speed of operation, the level of compression of files when placed in the archive, and the manual nature of the search engine. Most archiving programs have approximately the same capabilities, and each of them does not exceed others in all parameters: some programs work faster, while others provide a shorter level of file compression. However, if you compare programs only step by step, there is no leader among them: different files are more likely to be compressed by different programs. The principle of operation of archivers is based on the search for “excessive” information in the file and further encoded using the method of removing the minimum obligation. The most common method of archiving files is to compress the sequences of new characters. For example, in the middle of the file there are sequences of bytes that are often repeated. Instead, in order to save every byte, a number of characters are recorded that are repeated in their position. For example, the file being archived takes up 15 bytes and consists of the following characters: B B B B B L L L L L A A A A A

Slide 3

In a sixteenth system 42 42 42 42 42 4C 4C 4C 4C 4C 41 41 41 41 41 The archiver can present this file to the next view (sixteenth): 01 05 42 06 0 5 with 4 B" from position ї 6 The symbol " is repeated five times L" and from position 11, the symbol "A" is repeated five times. To save a file in this form, only 9 bytes are required, which is 6 bytes less than the previous one. The described method is a simple and effective way to compress files. However, not will ensure great savings in that the text is marked with a small number of sequences of characters that are repeated. In this case, the optimal prefix code and coding with the symbols of the changeable dozhin (algorithm Huffman). For example, in any English text the letter E is sharpened more often than Z, and X and Q are raised to those that are sharpened the least. In this way, using a special table of appearance, you can encode the letter E with a smaller number of bits and use a larger code for rare letters.
On the menu

Slide 4

Popular archivers ARJ, PAK, PKZIP work based on the Lempel-Ziv algorithm. These archivers are classified as adaptive dictionary coders, in which text rows are replaced by indicators on identical rows as previously in the text. For example, all words of any book can be represented by the page numbers and row numbers of a book. The most important feature of this algorithm is the grammatical analysis of the previous text and its division into phrases that are recorded in the dictionary. Customizers allow you to send messages to any phrase in a window of a specified size that conveys the exact phrase. Once a match is found, the exact phrase is replaced by the author with its previous counterpart. When archiving or compressing, the stage of file compression depends on the file format. Graphic files of the TIFF and GIF types are already compressed (although there are different types of TIFF format and without compression) and here you can find the most suitable archiver for packaging. A completely different picture emerges when archiving text files, *.BMP files and the like. All archiving programs can be mentally divided into two categories: For the MS-DOS command line (ARJ, PKZIP, RAR, etc.) For Windows (WINZIP, WINRAR, etc.)
On the menu

Slide 5

Archive file
An archive file is a collection of one or more files placed at a glance into a single file, from which they can be retrieved at a glance. The archive file contains a space that allows you to find out what files are located in the archive. Instead of an archive for each file, which is located in a new one, the following information is saved: file name; information about the directory where the file is located; date and hour of the last modification to the file; size of the file on disk and in the archive; cyclic control code for the skin file, which is checked to verify the integrity of the archive; This means that any other program has archived the same archive file, which can be expanded. For example: game.rar - archived using the RAR archiver. game.arj - archiving with the help of the archiver ARJ. game.zip – archived using a ZIP archiver. Unfortunately, food comes to the fore, so many archivers do it all for one thing – to compress the file. Various programs vary in the format of archive files, the speed of operation, the level of compression of files when placed in the archive, and the manual nature of the search engine.
On the menu

Slide 6

Archivers MS DOS
With the development of the computer, the amount of information that is stored in the new has increased, which in turn has led to the development of technology for storing valuable information in a compact form, like in archives. Why was a non-personal program invented to archive information? However, when working with valuable information, it is not necessary to open new archives to take one or two necessary files, or simply see what is in the archive for information. Archiving programs, to be sure, do not provide manual shells that allow you to simply, quickly, and in a basic form access archives instead. The most popular archiver programs for MS-DOS: ARJ (developed by Robert K. Jung), PKZIP (PKWARE Inc.), IHA (Haruyasu Yoshizaki), ZOO (Rahul Dhesi). For the last 5 years, the RAR archiver has become an undisputed leader in the whole world. Currently, RAR is actively promoting ZIP as the main utility for compressing FTP archives on the INTERNET. RAR is a single program that is worldwide copyrighted, created by a Russian program (under the auspices of TETRIS). All archivers are subject to compression algorithms, archive file formats, speed of operation, etc.
On the menu

Slide 7

PKZIP and ARJ
PKZIP Works from the command line. Various functions for maintaining zip archives are performed by various programs: pkzip - placing files in archives pkunzip - downloading files from archives zip2exe - creating an archive pkzipfix, which self-extracts - Lenny poskodzhenogo archive. Use the following commands to complete the work with the pkzip archiver: pkzip /h pkunzip /h zip2exe /h ARJ Work from the command line. Converts all functions of maintaining archives.arj, incl. There are even a lot of keys to support Arj's large-volume archives. You can automate a wide range of activities - creating a backup copy of a disk, archiving from a specific date, adding a stream date to the archive name (arh970821.arj), archiving a file from a specific location, and creating a unique archive And so on. Version 2.55 allows robots with longer names. Advantages: there are a lot of keys, which makes it possible to automate a large number of functions. Protect the archive for damage. Disadvantages: the presence of a dialog mode, the inability of the robot to detect any key in the changeover (ARJ_SW) and the startup sequence - mutually reduced.
On the menu

Slide 8

RAR
1. Enter the RAR Archiver to create a universal application for compressing files to accommodate a variety of information, which adds to the advantages and usability of the program of two classes of the command line archiver and completely ї shells for viewing and other manipulations with archives. In some cases, the RAR archive cannot be replaced with conventional archivers, and the logical and simple interface allows you to manually work with archives. In terms of its technical characteristics, RAR does not compromise with widely used and popular archivers, and in some respects it surpasses them. 2. Technical characteristics 2.1. Compression level On files such as .EXE, .COM, .LIB, .OBJ, .OVR and similar ones, RAR usually provides the maximum level of compression equal to other archivers, exceeding them by approximately 0.5 - 3% On the surrounding file x(great.lib , Other activities can reach 5-7% of the packaged size. The squeeze method does not affect the result at all. Text information is compressed approximately on par with other archivers (depending on the type of text and compression method) on files up to 32 kilobytes in size. On large text files, RAR outweighs most other archivers. When packing database files, the size and hours of work can be carried out using the compression method (m0 - m5). The level of compression of graphic information depends on the type of files. When creating a permanent (solid) archive to accommodate a lot of small files of the same type, the level of compression by 10 - 40% or more exceeds that achieved when packing into a primary archive
On the menu

Slide 9

2.2. Additional capabilities In addition to standard RAR functions, it provides an all-screen interface: selecting files to be packed and unpacked; emulation of the structure of subdirectories in the archive; robot with a "target"; saving parameters in the configuration file; View of packed and original files in text or hexadecimal view. Special functions: dividing the archive into parts (volumes) for transferring a floppy disk; creation and modification of self-extracting archives (SFX); creation of archived volumes to self-extract (SFX); creation of permanent (solid) archives from an advanced stage of compression; protection of information from passwords; protection of archives due to modification; saving information about the author in the archive; updating the structure of damaged archives; adding comments to the entire archive and to other files; ANSI escape sequence support has been introduced in comments. Working with ZIP, ARJ, LZH archives in full-screen mode: selecting files to be packed and unpacked, emulating the structure of subdirectories in the archives and identifying the main operations on archives
On the menu

Slide 10

On the menu
3.Work with RAR from the command line 3.1. Wiklik format: rar - There can be only one command, the keys can be as many as possible. The file list can contain the names of selected files, divisions, carriage rotations, or spaces. A file with a comment can contain a comment that is added to the archive upon creation, rather than modification. The unpacking path is combined with the commands “e” and “x”, indicating the subdirectory before which the unzipped files will be placed. If this subcatalog is new, it will be created. 3.2. Description of commands a: adds assigned files to the archive m: transfer assigned files and subdirectories to the archive. If the packaging is successfully completed, all specified files and subdirectories are deleted from the disk. All subdirectories will be entered only if the -ed key is not used, but because the names of the files that are added have been specified *.* or the names of the subdirectories. mf: transfer specified files to archives. If the packaging is successfully completed, all files are deleted from the disk. d: removes the specified files from the archive: selects the specified files from the archive with the updated subdirectory structure (if the -r key was specified during archiving). e: pulls assigned files from the archive to the current subdirectory v: browses instead of the archive. There is a new way to access the file and its name, file comment, unpacked and packaged size, packaging stage, date and hour of last modification of the file, its attributes, control sum, compression method and the minimum version of RAR, required for unpacking Nya. If it is necessary to look through all archived volumes, then the archive will be expanded instead of *.

Slide 11

Windows does not have any built-in functions for working with packaged archives, so most users have to acquire special utilities and thus deal with the problem of diversity of archive formats. The capacity of magnetic disks and RAM is steadily increasing, data transmission channels are becoming more and more complex, and yet the information that is transmitted and stored, as before, is lost even longer a significant factor that prompts us to use software for working with packaged data .
On the menu
WINDOWS Archivers

Slide 12

The WinRAR utility, developed by programmer Evgen Roshal, allows you to work with ZIP archives, and the main format for it is RAR (also developed by Roshal). In addition, it is possible to create EXE archives that self-extract, as well as use external programs for unpacking and viewing archives such as ARJ, LZH and CAB. The program creates large-volume archives in the RAR format.
On the menu
WinRAR 2.5

Slide 13

The RAR format is superior to ZIP, ARJ and LZH due to the efficiency of compression, so that the greatest advantage of this technology is manifested in the case of “permanent” archives, which do not allow changes to be made and are subject to further processing. but... The WinRAR distribution is an EXE file with a volume of approximately 650 KB, after installation the package takes up about 1.5 MB. Є versions of the archiver in English and Russian languages. The archiver window resembles the “My Computer” system utility; archives look and appear similar to the original folders. You can restore archives and extract objects from them using additional dragging. To view packaged files, the program uses a visualization module, or you can connect an external viewing utility. The program can complete the reporting system. Утиліта Е. Рошаля компактна, зручна, достатньо універсальна, її ціна не така приваблива, як у WinZip, але менше, ніж у інших лідерів цього огляду - ZIP Explorer Pro і Zip Magic, так що для багатьох WinRAR може стати найкращим вибором. WinRAR is a 32-bit version of the popular RAR archiver for Windows that allows you to create and manage archives.
On the menu

Slide 14

WinRAR features:
continued support for RAR and ZIP archives; original highly efficient data compression algorithm; special multimedia compression algorithm; wrapper using additional technology of drag & drop; command line interface; storage of archives in other formats (CAB, ARJ, LZH, TAR, GZ, ACE, UUE); support for continuous (solid) archives, at which levels of compression can be 10 - 50% greater, less so with extreme compression methods, especially when packing a significant number of small similar files; support of richly voluminous archives; Creates self-extracting (SFX) of basic and large-volume archives using standard or additional SFX modules; renewal of physically damaged archives; Other additional functions, for example, encryption, adding archived comments (with support for ANSI ESC sequences), maintaining a pardon protocol, etc.
On the menu

Slide 15

WinZip 7.0
Entry A smart, costless utility developed by Nico Mak Computing, perhaps the world's best-known archiving program for Windows. The EXE file from the WinZip distribution takes up about 940 KB, and after installing the program files it totals 2 MB. The program has features for manipulating archives and packaged files in ZIP, TAR, GZIP and CAB formats, and also allows you to connect external modules for working with ARJ, ARC and LZH files. All operations with archives can be compiled using additional drag and drop; all object names (including Cyrillic ones) are processed normally.
On the menu

Slide 16

Working with the program Finally, from the most extensive scenario of working with the additional WinZip program. Let's say directory XXXX has files X1, X2, ..., Xn. They need to be packaged into a single archive. We know the folder XXXX, we see the files X1, X2, ..., Xn (using the left mouse button and the Ctrl or Shift buttons). Then, after pressing the mouse to the right, select the Add to Zip command.
On the menu

Slide 17

Condensing Word documents (doc or rtf) into an archive provides significant savings in disk space (up to 95%). A very modest result is achieved when compressing html files (up to 80%). When collapsing graphic files, bmp can be compressed up to 99%, and when archiving tif, jpg, gif, storage savings are obviously up to 35, 25, 10%. However, when sending files by e-mail, it is necessary to take into account not only their physical size, but also their number, and it also takes an hour to process the request for sending the file “attached” to the sheet. It’s worth closing zip files before sending by e-mail and the fact that many of your correspondence are affected by all sorts of anti-virus programs and/or firewalls, which can easily ignore any doc file through oh "suspiciousness", and zip- file, shvidshe for everything, slip through.
On the menu
When specifying the name of the archive file, the zip extension does not have to be specified; all you need to do is enter the name (in our field “x”) and click on the Add button. The result is that the x.zip file appears in folder XXXX (you could have specified a different location).

Slide 18

Work interface
Through File you can create a new one, open or close archives, view the table of current archives - Favorites (formed by the user), browse through the current zip file, add an icon from a message to your desktop, and also create anything. with the archive itself (transfer , copy, rename, delete, distribute and link to postal services). Those who like to go everywhere at hand with the “master of tips” can select the Wizard mode (the button is next to the right one). The Actions menu opens a wide range of options (most of which are duplicated with special buttons): add (Add), delete (Delete), extract (Extract), look through files in the archive (View), see all files in the archive (Select All) and select tse diya (Ivert Selection). Here you can check archived files for viruses (Virus Scan) (for which, of course, it is necessary to have one of the anti-virus programs installed under Windows). You can create archives that “freeze” and convert them into an extracted exe file by selecting the Make .Exe File command (control is transferred to the WinZip Self-Extractor program). If you want to “spread” the archives so that they self-extract on floppy disks, select the Safe spanning method option. Among the additional possibilities of this menu: converting the archive file to a universal format sent by e-mail UUE, first checking the archive for unpacking, preparing a comment for the archive, creating a side menu in the section Start > Programs (CheckOut).
On the menu

Slide 19

An advanced test of the speed code and compression stage of the most popular archivers (WINRAR, WINZIP, RAR).
On the menu
Archivers Hour of compression (in sec.) End volume Compression level (in %)
WINRAR 851 276 MB (289,776,458 bytes) 97.08
WINZIP 59276 MB (290110408 bytes) 97.19
RAR 245167 MB (176049935 bytes) 58.98
Pochatkovy obsyag 284 MB (298,502,392 bytes)

Slide 20

An uninterrupted archive is a set of RAR archives that are packaged in a special way, in which all the files that are compressed are viewed as one sequential stream of data. Continuous archiving is only supported in the RAR format; in the ZIP format there is no such type of archive. The compression method for RAR archives—either emergency or continuous—is chosen by the user. Continuous archiving significantly increases the level of compression, especially when a significant number of small files of similar types are added to the archive. However, we note that continuous archiving has shortcomings: updating permanent archives (that is, adding files to an existing archive or deleting them) is more likely she, nizh svychaynyh; · in order to extract one file from a permanent archive, you need to analyze all the previous archived files, thus extracting adjacent files from the middle of a permanent archive is more efficient than the extraction from the initial archive Ivu. However, if all or a few of the first files are retrieved from the permanent archive, then in this case the speed of unpacking is practically comparable to the speed of unpacking the original archive; · If any file in the permanent archive turns out to be corrupted, then you will not be able to retrieve all the files that come after it.

Archiver.

back

  • What is an archiver?
  • Constriction of information.
  • Main types of archivers.
  • Archives are self-packed.
  • What are these voluminous archives?

What is an archiver?

back

Archivators It is one of the most advanced service programs used for archiving and packing files to compress information.

Archive file– this is a special way of organizing a file to hold one or a number of files, compressed or uncompressed, and service information (file names, date and time of creation, size, etc.)

back at the menu


Constriction of information.

back

Constriction of information– this is the process of transforming the information that is stored in a file to a form in which the size of the file changes and obviously requires less memory for saving

Information is being compressed for the removal of super-dimensionality in various ways, for example, for the purpose of simplifying codes, excluding constant beats from them, or supplying symbols that are repeated, in the appearance of a repetition rate.

For example, if in a text file the word “mother” is written 1000 times, then the size of the uncompressed file is 4000 bytes (4 bytes x 1000 times = 4000 bytes). If you compress this file, then the archiver will write the word “mother” in the archive just once, but remember that this word is compressed 4000 times. Thus, our text file will be compressed approximately 500 times.


Constriction of information.

back

Information compression level– this is one of the most important exhibits in the archive. Characterized by the coefficient Do, valued as the ratio of the compressed file V c to the output file V 0, expressed in hundreds (%).

The compression step should be placed in:

The kindest squeeze:

  • graphic files (*.bmp, *.png and others)
  • text files (*.doc, *.txt, *.xls etc.)
  • vikoriated program
  • squeeze method
  • output file type

It's a nasty squeeze files of compiled programs (*.exe, *.com) and downloaded modules (*.dll, for example) – 60-90%.

Mayzhe don't squeeze archive files Try to explain.

back at the menu


Archiver.

back

Archivators– these are programs that pack and unpack files.

Package(archiving) – placement (storing) of output files to archive files in compressed and uncompressed views.

Unpacking(Rozarchivatsiya) - the process of updating files from the archive in exactly the same way as it does little and attracting attention to the archives. When the files are unpacked, they are removed from the archive and placed on disk or RAM.

The most extensive of these archivers are:

name

archive formats that we support

*.rar, *.arj, *.ice, *.pak, *.zip, *.exe (self-propelled) and many others

*.ace, *.rar, *.arj, *.ice, *.pak, *.zip, *.exe (self-propelled) and many others

back at the menu

Context is not a menu.


Archiver.

back

Today, most clients work with WinACE and WinRAR, 7-Zip (and the rest are distributed in Russia). This is due to the fact that archivers use better compression methods, similar to WinZIP. In addition, they allow you to create archives that unpack themselves.

back at the menu


back

Main features of the programs:

  • Possibility of operation in two modes - a full-screen interactive interface and a basic command line interface
  • support for other types of archives (*.rar, *.arj), reviewing them instead, changing and re-creating
  • Vykoristannya highly effective method of compression solid (without interruption), which increases the degree of compression by 10-50%
  • Possibility of creating self-extracting and multi-volume archives
  • Protect the archive by changing the password (locking)
  • the possibility of frequent and thorough updating of damaged archives
  • You can find a lot of other archiver functions (more than 15) in the manual.

back at the menu


The 7-Zip archiver supports work with a wealth of archive formats. It has a simple and intuitive interface: you can work in single disk mode, or you can work with archives/files using 2 disk panels (similar to the file manager).

This program uses the official 7z archive format. The level of constraint in this case is simpler than that of the popular archive formats ZIP and RAR, because the process of archiving files in this format is more troublesome.

7-Zip supports working with current archive formats: 7z, ZIP, RAR, ARJ, GZIP, BZIP2, TAR, CPIO, RPM and DEB. The ability to create archives to self-unpack has been improved.


Archives are self-packed.

back

Archives are self-packed- this is a unique module that can be compiled, which can be created for independent unzipping of files located in the new one, without using the archiver program.

created in

SFX archive,

created in

Archiving programs allow you to create archived files, but you don’t need any programs to extract them, because The archive files themselves may interfere with the unpacking program. These files are called self-unpack archives. Most often, such archives have the extension *.exe. These archives are called SFX archives (as S el F -e X tracting).

This addition, which is called the SFX module, increases the size of the archive by 35 kilobytes. To be clear: the new formatted 3.5” floppy disk has 1400 kilobytes.

back at the menu


Rich volume archives.

back

One of the most important advantages of the WinRAR archiver is the ability to create large-volume archives. Archives require two or more floppy disks to accommodate them. The skin disc contains one or several volumes.

Also, the ability to work with volume-rich archives can be beneficial when working on the Internet, or more precisely when working with e-mail, if there is a limit on the size of sheets.

Bagatotomny archives– a series of archives that are “fragmented” into a number of parts (volumes), whereby: the first volume of a multi-volume archive has the extension *.rar, and the extensions of subsequent volumes are numbered as *.r00, *.r01, *.r02, etc. up to *.r99

back at the menu

Uninterrupted archive

back

Uninterrupted archive- a set of RAR archives, packages special in a way in which all files that are squeezed are viewed as one sequential flow of data. Continuous archiving is only supported in the RAR format; in the ZIP format there is no such type of archive. The compression method for RAR archives—either emergency or continuous—is chosen by the user.

Uninterrupted archiving significantly greater level of compression, especially when a significant number of small files with similar ones are added to the archive. However, the mother’s trace is respected, so that continuous archiving may and activities not enough :

· renovation permanent archives (that is, adding files to an existing archive or deleting them) is required more than the emergency ones;

· shob When you pull one file from a permanent archive, you have to analyze all the previous archived files, then extracting adjacent files from the middle of a permanent archive is more efficient than extracting from the original archive. However, if all or a few of the first files are retrieved from the permanent archive, then in this case the speed of unpacking is practically comparable to the speed of unpacking the original archive;

· yakscho In a permanent archive, if any file turns out to be corrupted, you will not be able to retrieve all the files that come after it.