A program for working with archives. Archiver programs

Archiving is the compression of one or more files to save memory and placing the compressed data in a single archive file. Data archiving is the reduction of the physical size of the files in which data is stored, without significant information loss.

Archiving is performed in case:

§ the need to create backup copies of the most important files;

§ the need to free up disk space;

§ the need to transfer files by E-mail.

An archive file is a set of several files (one file) placed in a compressed form into a single file, from which they can be extracted in their original form, if necessary. The archive file contains a table of contents that lets you know what files are contained in the archive.

File name;

§ file size on disk and in the archive;

§ about the location of the file on the disk;

§ date and time of the last modification of the file;

§ Cyclic control code for the file, used to check the integrity of the archive;

§ compression ratio.

Any archive has its own scale of compression ratio. The most common gradation of compression methods is:

§ without compression (corresponds to the usual copying of files into an archive without compression);

§ high-speed;

§ fast (characterized by the fastest, but least dense compression);

§ normal;

§ good;

§ maximum (maximum possible compression is also the slowest compression method).

The compression ratio depends on:

used archiver;

compression method;

the type of the source file.

The compression ratio is characterized by the compression ratio:

where V c is the size of the compressed file;

V and - the volume of the source file.

Different file types are compressed in different ways. For example, the compression ratio of text documents is significantly higher than that of graphic documents.

Archivers are used to compress files.

Archivers are programs (a set of programs) that compress and restore compressed files in their original form.

The process of compressing files is called archiving. The process of recovering compressed files is by unzipping.

Modern archivers differ in the algorithms used, the speed of work, the compression ratio (WinZip 9.0, WinAce 2.5, PowerArchiver 2003 v. 8.70, 7Zip 3.13, WinRAR 3.30, WinRAR 3.70 RU).

WinRAR archiver

WinRAR is a 32-bit version of the RAR archiver for Windows. It is a powerful tool for creating and managing archives. There are several versions of RAR for different operating systems: Windows, Linux, UNIX, DOS, OS / 2, etc.

There are two versions of RAR for Windows:

§ version with graphical user interface - WinRAR.EXE;

§ console version RAR.EXE command line console (text mode) version - Rar.exe

WinRAR features:

§ allows you to unpack archives CAB, ARJ, LZH, TAR, GZ, ACE, UUE, BZ2, JAR, ISO, and provides data archiving in ZIP and RAR formats;

§ provides full support for ZIP and RAR archives;

§ has special algorithms optimized for text and graphics. For multimedia, compression can only be used with RAR formats;

§ supports drag & drop technology;

§ has a command line interface;

§ can perform continuous archiving, which provides a higher compression ratio compared to conventional compression methods, especially when packing a large number of small files of the same type;

§ provides support for multivolume archives, that is, it splits the archive into several volumes (for example, to write a large archive to disks). Volume expansion: RAR, R01, R02, etc. In a self-extracting archive, the first volume has the EXE extension;

§ creates self-extracting archives (SFX), regular and multivolume archives, provides password protection;

§ provides recovery of physically damaged archives;

§ has recovery tools that allow you to restore missing parts of a multivolume archive;

§ supports UNICODE in filenames;

§ For beginners, the Wizard mode is intended, with the help of which you can easily carry out all operations with archives.

WinRAR has other additional features as well. WinRAR is capable of creating an archive in two different formats: RAR and ZIP. Let's take a look at the advantages of each format.

ZIP archive

The main advantage of the ZIP format is its popularity. For example, most archives on the Internet are ZIP archives. Therefore, it is best to submit an email attachment in ZIP format. You can also send a self-extracting archive. This archive is a bit large, but can be extracted without external programs. Another advantage of ZIP is speed. ZIP archive is usually faster than RAR archive.

Archive in RAR format

The RAR format provides significantly better compression than ZIP in most cases. In addition, the RAR format provides support for multivolume archives, has tools for recovering damaged files, and archives files of almost unlimited sizes. It should be noted that when working in the FAT32 file system, archives can only reach 4 gigabytes. Working with large archive sizes is supported only in the NTFS file system.

Microsoft Backup archiving program (backup copy).

The program is launched: Start - Programs - Standard - Service - Data archiving. This will open the Backup and Restore Wizard in normal mode. From this mode, you can switch to advanced mode to work with the backup wizard, recovery wizard and OS disaster recovery wizard.

The archiving program allows you to protect data from accidental loss in the event that a hardware failure or media failure occurs in the system. With Backup, you can back up your data to your hard drive and then create an archive on another storage medium. The archive medium can be a logical disk or a separate device (removable disk).

The backup software creates a snapshot of the volume, which is an exact copy of the disk contents at a specific point in time, including open files used by the system. During the execution of the backup program, the user can continue to work with the OS without the risk of data loss.

The archiving program provides the following features:

1. Backing up selected files and folders in case of hard disk failure or accidental deletion of files (you can back up to a hard disk or removable disk, etc.). Backup restores archived files and folders to your hard drive.

2. Archiving system state data. The program allows you to back up copies of important system components such as the registry, boot files, and the directory service database. The backup utility allows you to restore copies of important system components such as the registry, boot files, and the directory service database.

When using a computer, one of the most useful utility programs is archiver program.

An archiver is a program that provides data compression or packing. Compression is such a presentation of information in which it takes up much less volume in bytes. The compression process itself is called archiving, and the compressed information is called archival information, or simply an archive. The reverse process is called decompression or expansion.

The need to back up information arises when there is not enough free space on the disk drive. Modern archiving programs reduce the amount of memory that information occupies, on average, two times for programs, four times for text documents, and ten times for graphic images.
Information compression is always based on the principle of eliminating redundant information, for which each archiving program, of course, uses its own patented method.
Of course, archiving programs are not part of any operating system. They need to be purchased and installed on your computer separately. Although windows XP was already able to work with zip archives.
Currently, the most popular archivers are WinRar, WinZip, 7-Zip. They have a rather different interface and archiving methods, but they perform the same functions:
-adding files to archives
-receiving files from archives (opened archives
-testing archives for damage
- removal of files from archives
-viewing the contents of archives, viewing the contents of archive files
-creation of multivolume archives (that is, splitting archives into files of a certain size, which are very convenient to transfer on information storage devices, for example, on disks or flash drives)
-creation of SFX-archives (SFX is an abbreviation for the English SelF Extracting - unzips itself), that is, archives that do not need an archiver program to unzip. Such archives are executed in the form of exe-files, after which the archive is opened.
-setting a password for the archive in such a way that only those who know the password could unpack it and view its contents
-additional features.
Of course, archiving programs cannot process some archives that were created by other archivers.

WinRAR is a popular archiver from domestic developers. Judging by the statistics, it is WinRAR that is the most popular archiver in the world. It is understandable, the compression algorithm of the RAR format is rightfully considered one of the best. A user-friendly interface, support for all necessary archiving formats and a very high overall quality leaves no chance for competitors. WinRAR has full support for RAR and ZIP formats, and can also perform all basic operations with formats: 7Z, ACE, ARJ, BZ2, CAB, GZ, JAR, LZH, TAR, UUE, Z and ISO (disk images). Knows how to create self-extracting archives like SFX.

7-Zip
First of all, this archiver is valuable for its own 7z format. It is believed that this format has the highest compression ratio and is excellent for archiving large amounts of information (for example, especially large programs or games). The following formats are also supported: ZIP, CAB, RAR, ARJ, GZIP, LZH, CHM, BZIP2, TAR, CPIO, RPM and DEB. It is worth paying attention to frequent situations in which the compression ratio of the ZIP and GZIP formats in this program is an order of magnitude higher than that of competitors.

7-Zip is completely free, and since this is an infrequent occurrence among programs of this kind, this fact is another good argument in its favor.

WinZip
WinZip is a program that has gained worldwide popularity due to the fact that it was the first graphical archiver. WinZip still has the nicest and most advanced interface in terms of functionality with a lot of convenient options for working with archives. The program supports most of the popular archiving formats, including the most popular ones: ZIP, RAR, GZIP, 7Z, ARJ, ARC, CAB, LZH, TAR, MIME, Unix Compress, Uuencode, Xxencode, BinHex. Additional features include a backup tool, encryption functions, sending archives by email, and more.

ExtractNow
ExtractNow is a small utility for unpacking archives. ExtractNow is used for quick unpacking of several archives by pressing just one button. This is useful in cases where the user needs to regularly unpack a lot of zipped files. To do this, you just need to drag the archives that you want to unpack into the program window and click the Extract button. The program supports all popular archive formats: zip, rar, 7z, bzip2, arj, cab, iso, chm, tar, gzip, as well as many less popular ones.

ExtractNow is not an archiver and does not support creating archives. The modest possibilities of the program are limited only by the above unpacking function. Actually, the program can't do anything else.

In general, there are universal archivers that can extract files from various structures, so they are more preferable, although all programs work quickly and compress data well. And we owe the appearance of applications of this kind to K. Scannon, who laid the foundations of the theoretical basis for computer archiving. He was the founder of information coding theory, built on an offshoot of probability theory and mathematical statistics.

Topic 1.3: System Software

Topic 1.4: Service software and the basics of algorithmization

Introduction to Economic Informatics

1.4. PC service software and algorithms basics

1.4.1. Service software (standard and utility programs, data archiving, anti-virus programs)

1.4.1.2. Data archiving programs

Archiving is carried out in the following cases:

when you need to back up your most valuable files;
when you need to free up disk space;
when it is necessary to transfer files by E-mail.
An archive file is a set of several files (one file) placed in a compressed form into a single file, from which they can be extracted in their original form, if necessary. The archive file contains a table of contents that lets you know what files are contained in the archive.
- File name;
- file size on disk and in the archive;
- information about the location of the file on the disk;
- date and time of the last modification of the file;
- Cyclic control code for the file, used to check the integrity of the archive;
- compression ratio.
Any of the archives has its own compression ratio scale. Most often you can find the following gradation of compression methods:
1. Uncompressed (corresponds to the usual copying of files into an archive without compression).
2. High-speed.
3. Fast (characterized by the fastest but least dense compression).
4. Normal.
5. Good.
6. Maximum (the highest possible compression is also the slowest compression method).
Bmp graphics files, MS Office documents, and Web pages are best archived.

What are archivers?

Archivers are programs (a set of programs) that compress and restore compressed files in their original form. The process of compressing files is called archiving. The process of recovering compressed files is by unzipping. Modern archivers differ in the algorithms used, the speed of work, the compression ratio (WinZip 9.0, WinAce 2.5, PowerArchiver 2003 v.8.70, 7Zip 3.13, WinRAR 3.30, WinRAR 3.70 RU).

Other names for archivers: utilities - packers, programs - packers, utilities that allow you to put copies of files in compressed form in an archive file.

There are archivers in MS DOS, but they work only in the command line mode. These are PKZIP and PKUNZIP programs, ARJ archiver program. Modern archivers provide a graphical user interface and retained the command line. Currently, the best archiver for Windows is WinRAR.

WinRAR archiver

WinRAR is a 32-bit version of the RAR archiver for Windows. It is a powerful tool for creating and managing archives. There are several versions of RAR for different operating systems: Windows, Linux, UNIX, DOS, OS / 2, etc.

There are two versions of RAR for Windows:
- version with graphical user interface - WinRAR.EXE;
- Console version RAR.EXE command line console (text mode) version is Rar.exe.
Fig. one.

WinRAR features:
1. Allows you to unpack archives CAB, ARJ, LZH, TAR, GZ, ACE, UUE, BZ2, JAR, ISO, and provides data archiving in ZIP and RAR formats.
2. Provides full support for ZIP and RAR archives.
3. Has special algorithms optimized for text and graphics. For multimedia, compression can only be used with RAR formats.
4. Supports drag & drop technology.
5. Has a command line interface.
6. Can perform continuous archiving, which provides a higher compression ratio than conventional compression methods, especially when packing a large number of small files of the same type.
7. Provides support for multivolume archives, that is, it splits the archive into several volumes (for example, to write a large archive to disks). Volume expansion: RAR, R01, R02, etc. In a self-extracting archive, the first volume has the EXE extension.
8. Creates self-extracting archives (SFX), regular and multivolume archives, provides password protection.
9. Provides recovery of physically damaged archives.
10. Has recovery tools that allow you to recover missing parts of a multivolume archive.
11. Supports UNICODE in filenames.
12. For beginners, the Wizard mode is intended, with the help of which you can easily carry out all operations with archives.
WinRAR has other additional features as well. WinRAR is capable of creating an archive in two different formats: RAR and ZIP.
Let's take a look at the advantages of each format.

ZIP archive

The main advantage of the ZIP format is its popularity. For example, most archives on the Internet are ZIP archives. Therefore, it is best to submit an email attachment in ZIP format. You can also send a self-extracting archive. This archive is a bit large, but can be extracted without external programs. Another advantage of ZIP is speed. ZIP archive is usually faster than RAR archive.

Archive in RAR format

the RAR format provides significantly better compression than ZIP in most cases. In addition, the RAR format provides support for multivolume archives, has tools for recovering damaged files, and archives files of almost unlimited sizes. It should be noted that when working in the FAT32 file system, archives can only reach 4 gigabytes. Working with large archive sizes is supported only in the NTFS file system.

Microsoft Backup Archiving Program (backup)

The program is launched: Start - Programs - Standard - Service - Data archiving. The Backup and Restore Wizard will open normally. From this mode, you can switch to advanced mode to work with the Backup Wizard, Recovery Wizard, and OS Disaster Recovery Wizard.

Fig. 2.

The archiving program allows you to protect data from accidental loss in the event that a hardware failure or media failure occurs in the system. With Backup, you can back up your data to your hard drive and then create an archive on another storage medium. The archive medium can be a logical disk or a separate device (removable disk).

The backup software creates a snapshot of the volume, which is an exact copy of the disk contents at a specific point in time, including open files used by the system. During the execution of the backup program, the user can continue to work with the OS without the risk of data loss.

The archiving program provides the following features:
1. Back up selected files and folders in case of hard drive failure or accidental deletion of files (you can archive to hard drive or removable drive, etc.). Backup restores archived files and folders to your hard drive.
2. System state data archiving. The program allows you to back up copies of important system components such as the registry, boot files and the directory service database. The backup utility allows you to restore copies of important system components such as the registry, boot files, and the directory service database.

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Ministry of Agriculture of the Russian Federation

Transbaikal Agrarian Institute - branch of the Federal State Budgetary Educational Institution of Higher Education

Irkutsk State University named after A.A. Ezhevsky "

On the topic: Data archiving. Archivers

By: Informatics

Completed: 1st year student

A. V. Konshin

Checked by: Kolosova O.E

Introduction

archiving packaging huffman

Nowadays, most of us often use the Internet and often come across information archived by various programs - archivers. This course work is devoted to the study of data archiving using the example of the WinRAR program.

The purpose of this course work is to disclose the concept of data archiving, studying the information compression algorithm, archiver programs and the process of packing and unpacking files using the WinRAR archiver program. Also, the aim of the course work is to consolidate knowledge and skills in working with Microsoft Word, Microsoft Excel, Microsoft Access.

Archivers are programs that allow you to reduce file size to save disk space. Their work is as follows: find duplicate fragments in files and write information about the number of duplicate fragments instead of them. They can be divided into two classes: packers (archivers) and backup programs.

In the course of writing this term paper, I use the knowledge acquired in computer science classes on the use of Microsoft Office XP programs: Microsoft Word, Microsoft Excel, Microsoft Access.

With Microsoft Word, I can create, edit, format, save and print documents. The Microsoft Word word processor has a wide range of document creation capabilities (inserting lists and tables, spell checkers, saving, correcting, etc.)

Microsoft Excel is a spreadsheet management program. A spreadsheet allows you to process large amounts of numerical data, such as experimental results, statistics, etc.

Microsoft Access is a database management system included in Microsoft Office that allows you to create databases, as well as provide processing (sorting) and data retrieval.

Data archiving (using the WinRaR program as an example)

Formulation of the problem. Write an abstract on a given topic on 12 - 15 printed sheets. In the abstract, provide for the use of bulleted and numbered lists, insertion of a special character, insertion of a footnote, figure, design of one of the paragraphs in the form of two columns.

Understanding File Archiving

One of the most widespread types of service programs are programs designed for archiving by compressing the information stored in them.

Compression of information is the process of converting information stored in a file into a form in which redundancy in its representation is reduced and, accordingly, less memory is required for storage.

Compression of information in files occurs by eliminating redundancy in various ways, for example, by simplifying codes, eliminating constant bits from them, or representing repeating symbols or a repeating sequence of symbols in the form of a repetition rate and corresponding symbols. Various algorithms for such information compression are used.

One or several files can be compressed, which in a compressed form are placed in a so-called archive file or archive.

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

The compression ratio of files is characterized by the coefficient Кс, defined as the ratio of the volume of the compressed file Vc to the volume of the original file V о, expressed in percentage:

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

Unpacking (unpacking) - the process of restoring files from the archive exactly as it was before loading into the archive. When unpacking, the files are extracted from the archive and placed on disk or in RAM.

Archiving methods

There are two main archiving methods:

Huffman algorithm. The algorithm is based on the fact that some characters from the standard 256-character set in free text can occur more often than the average repetition period, while others, respectively, less often. Therefore, if you use short sequences of bits less than 1 byte long to write common characters, and longer ones to write rare characters, then the total file size will decrease. For example, the letters a, o, e, and - are very common in Russian text, the size of each letter is 1 byte (8 bits), they can be replaced with numbers 0,1,2,3, which can be placed in 2 bits. Those. the compression ratio will be 25%.

Lempel-Ziv algorithm. The classic Lempel-Ziv algorithm is LZ77, named after the year of its publication. It is formulated as follows: "if a similar sequence of bytes has already been encountered in an earlier text, then only a link to this sequence (offset, length) is written to the archive file, and not the text itself." So the phrase “BELL_BALL_BALL” is encoded into the sequence “KOLO (-4.3) _O (-6.4) _ (- 7.7) NI”. The compression ratio is 54%. The image is compressed in the same way. Large areas of the same color are replaced with a link: (color, length).

Archiving purposes

Archiving is used as a means to reduce the size of a file - the archive of a file, as a rule, takes up less space than in the normal state, and is mainly used for the following purposes:

· Free up space on your computer's hard drive.

· Reducing the volume of files sent by email.

· Placement of data on a single media.

· Placement of 1 large file on multiple media when it does not fit on 1 media.

· Unpack compressed files.

Programs - archivers

The programs that pack and unpack files are called archiving programs.

Archive files that are large in size can be located on multiple disks (volumes). Such archives are called multivolume. A volume is an integral part of a multivolume archive. By creating a multi-part archive, you can write the parts to multiple floppy disks.

Currently, several dozen programs are used - archivers, which differ in the list of functions and operating parameters. Among the most popular programs are:

WinZip, version 8.0 is perhaps the most famous archiver. It is the most popular archiver used on the Internet. It is often free or included in some other program as a free bonus. Beginning with the ME (Millenium Edition), WinZip is included even in Windows systems. In addition, there are many modifications of the WinZip archiver, such as zip - magic, 7 - zip, g - zip, etc., which differ in compression efficiency.

WinRar- the author of the program is Evgeny Roshal. The single-user system will cost you $ 29. You can download the test (trial) version from the website www.RaRlab.com. WinZip's main competitor on the Internet. Possessing the best characteristics, it gradually crowds out other formats, but so far it cannot cope with the authority of WinZip. A convenient (russified) interface and a fairly high speed of work in combination with low system requirements promise WinRar a good future.

WinAce 2.0- a fresh version of the old archiver, enriched with very interesting functions and a new compression algorithm. This archiver uses the largest dictionary size for archiving (4 MB), which largely explains its high results.

There are highly specialized archivers that can work with only one file format, such as SfArk, which can only compress audio files in the SF2 format. The WavPack archiver perfectly "compresses" sound files in the wav format. DJVU archiver specializes in compressing scanned images. There is also a whole galaxy of universal archivers such as UFA, 777, ACB, IMP, LZOP, UHARC, BOA, Arhangel.

There are many different archivers. The effectiveness of a particular archiver depends on several factors:

1. The content of the compressed file (text, graphic, sound).

2. From what program is selected as the archiver.

3. From the settings of the program - archiver.

Types of archive files

In the file system of a computer, archive files have a strictly specified type (extension). So, the most common archives are of the type: ZIP, RAR, ARJ.

In addition to them, archives are used on computers: CAB, LZH, TAR, GZ, UUE, BZ2, ISO, etc.

Packing files

Let's consider working with the WinRaR archiver. There are three different ways to package a file.

· Using the WinRaR packaging wizard.

· Using the Windows context menu, if you have embedded WinRaR into the shell.

Directly in the WinRaR program itself, without the help of the wizard, by clicking on the button Add to or using the context menu of the WinRaR program itself.

Let's consider all three ways.

Package files using the wizard

Ш Click the button Master the first dialog will appear on the screen Masters(fig. 1.1).

Figure 1.1 First Dialogue Master: Selecting actions

Ш To pack, click on the radio button Create new archive, then on the button Further.

Ш In the dialog that appears, click on the button of the drop-down list Folder and select the drive where the files you want to pack are located - click on the drive letter with the mouse (Fig. 1.2).

Fig. 1.2. Dialogue Select the files to add

Ш Select in the working field of the dialog the folder or file that you will pack - select them. Click the button OK.

Figure 1.3. Dialogue Choicenames for future archive

Ш A dialog will appear on the screen Wizard: Select Archive as shown in fig. 1.3. In the input field Archive name enter the name of the future archive.

Ш Click the button Further... A dialog will appear on the screen Wizard: Archiving Options as shown in Fig. 1.4. In this window, you can make certain settings for archiving, check the boxes in the corresponding fields.

Fig. 1.4. Dialogue Wizard: Archiving Options

Ш Click the button Done, thereby starting the packaging process.

Fig. 1.5. Dialogue Archive creation

After the words Archive creation the name of the future file is displayed in the dialog name (Fig. 1.5). The archive file will be located in the same location as the original folder.

Packing files from the Windows context menu

Let's zip the text file created earlier in Microsoft Word. If during the installation of the archiver you chose EmbedWinRaRin a shell, you can do this:

Ш Go to the file on the disk using Windows Explorer.

SH Right click on the file.

Ш Click in the context menu on the line Add to archive

Ш In the window that appears (Fig. 1.6), click on the button OK.

Fig. 1.6. Dialogue Name and parametersarchive

Packing files from the WinRaR program itself

Packaging from the WinRaR program itself provides more options than the previous two methods. In this method, you can implement the program settings in the most complete way. First, let's zip a text file created earlier in Microsoft Word.

Ш Open WinRaR.

Ш In the file window, select the file to pack, then click the button Add. A dialog will appear on the screen Archive name and parameters with an open tab General(Figure 1.6.)

Ш Click the button OK... The archive file will be created in the same location as the original files.

Packaging directly from the WinRaR program in this case is almost no different from packaging from the Windows context menu.

Only in the latter case it was necessary to launch the WinRaR program first, while in the first case it was launched automatically.

Archiving profiles

You can perform all the settings yourself or use the ready-made settings made by the author of the program by clicking on the button Profiles, as shown in Fig. 1.6. There are only 5 profiles here, the most suitable, in the opinion of the author of the programs, for solving the most urgent tasks during archiving:

· Default profile- nothing will change, until the pack you want to change the default profile itself.

· Attaching toe - mail- the most optimal for creating an archive, which will then be sent by e-mail.

· Backup of selected files- optimal for creating an archive with files important to you.

· Volumes of 1.44 MB- the archived file will, if necessary, be automatically split into several files (they are called volumes) with a size of 1.44 MB - so that each of them will fit on a standard floppy disk.

· Zip- archive(low compression ratio) - select it if you want to create an archive in the format zip.

If you are not completely satisfied with the existing profiles, you can create your own in any number. First, you need to make the desired settings on the corresponding tabs of the dialog. Archive name and parameters as shown in Fig. 1.6.

Ш Then open the tab General, then click the button Profiles and in the resulting context menu - on the line Save the current setting as a new profile. A dialogue appears on the screen Profile parameters as shown in Fig. 1.7.

Fig. 1.7 Dialogue Profile parameters

Ш In the input field Profile name type in the desired name - after saving it will be displayed in the list when you click on the button Profiles.

Ш Save the profile.

Archive format, compression method and volumes

Settings on the tab General... In a group of controls Archive format choose in which format you want to create the archive - zip or RaR.

Ш Click on the required radio button.

Ш In the drop-down list of the same name, select Compression method... Remember that speed and compression are closely related to each other. The higher the speed, the lower the compression ratio and vice versa.

If you need to split the archive into several parts, use the drop-down list Divide into volumes in size (in bytes). The created archive will be divided into several files of the same size - pieces, each of which will be assigned a serial number.

Archiving options

Let's move on to the next group of controls (Fig. 1.6) - Archiving options.

· Delete files after packing... If you select the checkbox, the original files will be deleted immediately after packing - only the created archive will remain.

· When you select the Create SFX - archive checkbox, a self-extracting archive will be created (SFX is an abbreviation of the words Self Extractor), a wonderful feature provided by the archiver.

Fig. 1.8. Dialogue Self-extracting archive

The next control is Create continuous archive... Check the box if you want to increase the compression ratio even more.

· Add electronic signature - an electronic signature will be added to the archive, containing the name of the author who created the archive, the date of the last update and the original name. This setting is only available in a registered program.

· Add information for recovery — when the checkbox is checked, the information for recovery will be written to the archive, which will be used in case of archive damage. The size of the archive will increase slightly (by default, by 1% of the original text).

To do this, follow these steps.

Check the box Dadd recovery information.

Go to the tab Dadditionally by clicking on its shortcut with the mouse, and in the field Recovery information enter in the input field with the counter% of the total archive size.

· Test the file after packaging- if you check the box, then after packing the archive will be checked for errors. If you also check the box at the same time Delete file after packing, then the original files will be deleted only if the newly created archive does not contain errors.

· Lock archive. When the checkbox is checked, it will be impossible to change the created archive - it will no longer be possible to add files to it or delete files from it, etc. Although you can unpack the archive just like any other.

Creating a multivolume self-extracting archive

The new file is saved in the folder My documents.

Find the file and right-click on it. In the menu that opens, click on the line add to archive. A dialog will appear Archive name and parameters.

After that, you need to make the necessary settings for the archiver.

Ш On the tab General click on the dropdown button Divide into volumes in size (in bytes) and select the item Auto detect.

You will need to select the location where the file will be archived. In this case, it is a floppy disk.

Open the floppy disk - click on the browse button, a dialog will open Archive search... Click on the drop-down list Folder, then when the list opens, on the line Disk 3.5 A and then on the button Open.

As a result, the path to the floppy disk will be indicated in the Archive name input field.

W Click OK. A dialog will appear on the screen Archive creation.

All files and folders on the floppy disk will be deleted. Instead of them, one of the archive volumes will be written. After the free space on the first floppy disk runs out, a dialog will appear on the screen Next volume... Remove the floppy disk from the floppy drive, insert a new one and click on the button Create a... Continue this way until the last archive file is created.

A multi-volume self-extracting archive is created and written to floppy disks.

Unpacking files

Just like packing, files can be unpacked in at least three ways:

· Using the WinRaR wizard.

· From the Windows context menu.

· From the WinRaR program itself, without using the wizard.

Unpacking files using the WinRaR wizard

Ш Open WinRaR.

Ш Start the wizard. In dialogue Wizard: Selecting Actions as shown in Fig. 1.1, click the switch Unpack the archive.

Ш A new wizard dialog will appear on the screen, which in this case will be called Wizard: Select Archive(Fig. 1.9).

Fig 1.9. Dialogue Master: Archive selection

Ш Select the archive you want to unpack.

Select the archive file, and then click on the button Open.

Dialogue reappears on the screen Wizards: Archive Selection... But the path to the file will now be displayed in the Archive name input field.

W Click Further.

A new dialogue will appear Wizard: Select folder for unpacked files.

Fig. 1.10. Dialogue Selecting a folder for unpacked files

W Click Done.

The archive will be unpacked, and a window with the folder into which the archive is unpacked will automatically open.

Unpacking an archive using the Windows context menu

Unpacking from the context menu is convenient because you do not need to find WinRaR in the start menu or on the Windows desktop every time - the context menu is always at hand. Finding the file you want to unzip is quite easy by the icon, in the form of a stack of books tied with a belt.

Find the file you want to unpack.

Ш Click the archive file with the right mouse button. Several lines related to unpacking will appear on the screen in the context menu:

· Extract files …

· Extract to current folder

Extract to Folder Name

Ш In the displayed context menu, click on the line Extract files. A dialog will appear on the screen Extraction path and parameters, as shown in Fig. 1.11.

Ш Click on the button OK... The archive will be unpacked.

Fig. 1.11. Dialogue Extraction path and parameters

Unpacking the archive directly from the WinRaR program

This method is no more difficult than the previous ones. In this case, you have much more opportunities than with other methods. For example, you can extract only part of the files from the archive or delete some files from the archive, you can even read the contents of the files if it is a simple text document.

Ш Start the WinRaR program.

Ш Open the disk where the archive is located.

The file window will display the contents of the root directory of the disk - i.e. all files and folders located in the root directory.

Find and highlight the archive file.

Ш Click on the button Extract... A dialog will appear on the screen Extraction path and parameters(Fig. 1.11.)

Ш Click the OK button. The archive will be unpacked to a folder on the disk.

Unpacking a self-extracting archive

Let's unpack a self-extracting archive written on several floppy disks.

Ш Insert the floppy disk containing the first self-extracting archive file.

Ш Open Windows Explorer, open the floppy disk in Explorer and make double cheeks on the file with the left mouse button. A dialog will appear on the screen Self-extracting archiveWinRaR.

Ш Using the button Overview select the drive or folder to unpack.

Ш To start unpacking, click on the button Extract... After a while, the program will ask for the next floppy disk in the dialog next volume is required.

Ш Insert the floppy disk and click the OK button.

Ш Repeat these steps until the dialogue RequiresXianext volume does not disappear from the screen.

You can do it differently. Open the first floppy disk in Explorer and copy the first archive file to some folder. Then everything, as in the previous case, only much faster.

Conclusion

In the course of this course work, I studied several algorithms for compressing information, revealed the concept of data archiving using the example of the WinRaR program. Now I know that an archiver is a program that creates archives - a special file in which a variety of files and folders can be compressed. Ultimately, it all boils down to two operations - packing into an archive and unpacking from it.

After completing the coursework, I can pack individual files and entire folders, extract files from archives, change, supplement archives. I can create a self-extracting archive that does not require any additional program to unpack.

Also, in the process of doing the work, I consolidated my knowledge and skills of working with Microsoft Word, Microsoft Excel, Microsoft Access programs.

Literature

1. E. Lemon, 2 and 1: Modern computer. Key topics + Video course: [tutorial] / ed. E. Lemon. - M .: Triumph, 2007.-320s.

2. Makarova NV, Informatics: Textbook / Ed. Prof. N.V. Makarova. - M .: Finance and statistics, 1997.-768 p .: ill.

3. Simonovich S.V. Computer science. Basic course / S.V. Simonovich. - SPb .: Peter, 2006 .-- 688 p .: ill.

4. Informatics. Microsoft Access XP: Methodological instructions for laboratory work for students of specialties 060803, 260100, 260200 I course of full-time education. - Krasnoyarsk: SibSTU, 2005 .-- 30 p.

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A program for working with archives. Archiver programs

Topic 1.3: System Software

Topic 1.4: Service software and the basics of algorithmization

1.4. PC service software and algorithms basics

1.4.1. Service software (standard and utility programs, data archiving, anti-virus programs)

1.4.1.2. Data archiving programs

WinRAR archiver

ZIP archive

Archive in RAR format

Microsoft Backup Archiving Program (backup)

Send your good work in the knowledge base is simple. Use the form below

Data archiving (using the WinRaR program as an example)

Formulation of the problem. Write an abstract on a given topic on 12 - 15 printed sheets. In the abstract, provide for the use of bulleted and numbered lists, insertion of a special character, insertion of a footnote, figure, design of one of the paragraphs in the form of two columns.

Package files using the wizard

Ш Click the button Master the first dialog will appear on the screen Masters(fig. 1.1).

Figure 1.1 First Dialogue Master: Selecting actions

Ш To pack, click on the radio button Create new archive, then on the button Further.

Ш In the dialog that appears, click on the button of the drop-down list Folder and select the drive where the files you want to pack are located - click on the drive letter with the mouse (Fig. 1.2).

Fig. 1.2. Dialogue Select the files to add

Ш Select in the working field of the dialog the folder or file that you will pack - select them. Click the button OK.

Figure 1.3. Dialogue Choicenames for future archive

Ш A dialog will appear on the screen Wizard: Select Archive as shown in fig. 1.3. In the input field Archive name enter the name of the future archive.

Ш Click the button Further... A dialog will appear on the screen Wizard: Archiving Options as shown in Fig. 1.4. In this window, you can make certain settings for archiving, check the boxes in the corresponding fields.

Fig. 1.4. Dialogue Wizard: Archiving Options

Ш Click the button Done, thereby starting the packaging process.

Fig. 1.5. Dialogue Archive creation

After the words Archive creation the name of the future file is displayed in the dialog name (Fig. 1.5). The archive file will be located in the same location as the original folder.

Packing files from the Windows context menu

Let's zip the text file created earlier in Microsoft Word. If during the installation of the archiver you chose EmbedWinRaRin a shell, you can do this:

Ш Go to the file on the disk using Windows Explorer.

SH Right click on the file.

Ш Click in the context menu on the line Add to archive

Ш In the window that appears (Fig. 1.6), click on the button OK.

Fig. 1.6. Dialogue Name and parametersarchive

Packing files from the WinRaR program itself

Packaging from the WinRaR program itself provides more options than the previous two methods. In this method, you can implement the program settings in the most complete way. First, let's zip a text file created earlier in Microsoft Word.

Ш Open WinRaR.

Ш In the file window, select the file to pack, then click the button Add. A dialog will appear on the screen Archive name and parameters with an open tab General(Figure 1.6.)

Ш Click the button OK... The archive file will be created in the same location as the original files.

Packaging directly from the WinRaR program in this case is almost no different from packaging from the Windows context menu.

Only in the latter case it was necessary to launch the WinRaR program first, while in the first case it was launched automatically.

Archiving profiles

· Default profile- nothing will change, until the pack you want to change the default profile itself.

· Attaching toe - mail- the most optimal for creating an archive, which will then be sent by e-mail.

· Backup of selected files- optimal for creating an archive with files important to you.

· Volumes of 1.44 MB- the archived file will, if necessary, be automatically split into several files (they are called volumes) with a size of 1.44 MB - so that each of them will fit on a standard floppy disk.

· Zip- archive(low compression ratio) - select it if you want to create an archive in the format zip.

If you are not completely satisfied with the existing profiles, you can create your own in any number. First, you need to make the desired settings on the corresponding tabs of the dialog. Archive name and parameters as shown in Fig. 1.6.

Ш Then open the tab General, then click the button Profiles and in the resulting context menu - on the line Save the current setting as a new profile. A dialogue appears on the screen Profile parameters as shown in Fig. 1.7.

Fig. 1.7 Dialogue Profile parameters

Ш In the input field Profile name type in the desired name - after saving it will be displayed in the list when you click on the button Profiles.

Ш Save the profile.

Archive format, compression method and volumes

Settings on the tab General... In a group of controls Archive format choose in which format you want to create the archive - zip or RaR.

Ш Click on the required radio button.

Ш In the drop-down list of the same name, select Compression method... Remember that speed and compression are closely related to each other. The higher the speed, the lower the compression ratio and vice versa.

If you need to split the archive into several parts, use the drop-down list Divide into volumes in size (in bytes). The created archive will be divided into several files of the same size - pieces, each of which will be assigned a serial number.

Archiving options

Let's move on to the next group of controls (Fig. 1.6) - Archiving options.

· Delete files after packing... If you select the checkbox, the original files will be deleted immediately after packing - only the created archive will remain.

· When you select the Create SFX - archive checkbox, a self-extracting archive will be created (SFX is an abbreviation of the words Self Extractor), a wonderful feature provided by the archiver.

Fig. 1.8. Dialogue Self-extracting archive

The next control is Create continuous archive... Check the box if you want to increase the compression ratio even more.

· Add electronic signature - an electronic signature will be added to the archive, containing the name of the author who created the archive, the date of the last update and the original name. This setting is only available in a registered program.

· Add information for recovery — when the checkbox is checked, the information for recovery will be written to the archive, which will be used in case of archive damage. The size of the archive will increase slightly (by default, by 1% of the original text).

To do this, follow these steps.

Check the box Dadd recovery information.

Go to the tab Dadditionally by clicking on its shortcut with the mouse, and in the field Recovery information enter in the input field with the counter% of the total archive size.

· Test the file after packaging- if you check the box, then after packing the archive will be checked for errors. If you also check the box at the same time Delete file after packing, then the original files will be deleted only if the newly created archive does not contain errors.

· Lock archive. When the checkbox is checked, it will be impossible to change the created archive - it will no longer be possible to add files to it or delete files from it, etc. Although you can unpack the archive just like any other.

Unpacking files using the WinRaR wizard

Ш Open WinRaR.

Ш Start the wizard. In dialogue Wizard: Selecting Actions as shown in Fig. 1.1, click the switch Unpack the archive.

Ш A new wizard dialog will appear on the screen, which in this case will be called Wizard: Select Archive(Fig. 1.9).

Fig 1.9. Dialogue Master: Archive selection

Ш Select the archive you want to unpack.

Select the archive file, and then click on the button Open.

Dialogue reappears on the screen Wizards: Archive Selection... But the path to the file will now be displayed in the Archive name input field.

W Click Further.

A new dialogue will appear Wizard: Select folder for unpacked files.