entranceFunctions and types of archives, principles and methods of archival. Archiving data What is the archive type of archives
What is the archive, file / data archiving, and archivers
Almost all novice users of the computer at a certain point are wondering, "What is the archive and archiving?" And, what kind of programs, "archivers", which allow you to work with them.
If you want to know what it really is, then this article will undoubtedly help you. After reading it, you will become a little bit, it's better to deal with computer technology.
Today we will consider in detail what the archive is what archives are and why the files and data are generally needed.
What is archive
The archive is inherently a container file in which other different types of files can be stored, which falling into it, thanks to compression, and decrease in size.
What looks from the inside
The archives are used for a convenient organization of storage of files and folders to reduce their size, to create various backups, as well as to transfer files via the Internet. All this is due to the fact that the entire structure of directories and files is fully saved in the archives, which makes it possible to work with them with comfort.
Subspecies of archives
1. Self-expanding archive. In essence, this is an executable file in the ".exe" format. It is enough to run it, and he himself unpacks where you specify.
2. Multi-volume archive. Consists of several parts, i.e. Located for several parts files. It is convenient to use it on large files, for example, to put on several smaller media.
3. Passed archive. As it is clear from the name to open it, you will need to enter a password. Very convenient to protect your information.
4. Continuous archive. All items in it are treated as one, which gives an increase in the degree of compression. But there are also cons - to extract some one element from it, you will have to wait until everyone else is unpacking, respectively, and when adding a new one, the time will also be longer.
What is file archiving and data
Archiving (archiving) is the process of creating an archive by packing files into it, it can occur both with data compression and without. The archived data itself during unzipping does not change from their initial state.
Archiving is done through special programs of "archivers", but also present in the default Windows OS. But, unfortunately in Windows, you can create an archive only in ".zip" format, which is not always convenient, because, most of the archives are made in another popular ".rar" format.
Archiving perfectly helps you increase the place on your hard drive, put in order a lot of files and organize a workspace on your computer.
What is archiver
The archiver is a special program designed to pack files to archive while squeezing them in size or on the contrary to unpack them from there.
The program to restore all files from the archive without losses to restore all files, when creating it saves the file metadata, such as: name, time creation, access rights, etc. Also, good archivers use only compression without losses to reduce the weight of the archive, which further allows you to unpack the data with an accuracy of the bit without loss of quality.
Depending on the type of files, the program will compress them differently, some will be compressed as text, which will give a significant decrease in their size, and some as binary. Binary, shrinking always in different ways, it all depends on their character, so, some can be strongly reduced in the amount, and some of their own characteristics should not be almost diminished.
Types of archivers - Best programs
Probably the most famous and popular archiver of all. It is famous in the first place with its interface and functionality, but also has a high speed of working with a good degree of compression. It turns out entirely in Russian and includes the support of almost all known types of archives, for example, such as: ".rar", ".zip", ".7z", etc.
Thanks to an intuitive interface, Virrar is ideal for newcomers.
The software is no less known than WinRar, but with simply stunning functionality. Allows you to work with almost all popular archive formats and has a Russian interface. According to its compression characteristics, one can say so - if you have 1 GB photo, you can reduce their weight with the benefit to 100MB with the help of vinzips, ultimately getting 900MB.
Also, a distinctive feature of this software, is synchronization with cloud services, which is quite convenient. But, unfortunately, the free use period is limited.
7-zip.
A popular special software of this kind, besides also free. It has a rather impressive functionality and its own compression format - ".7z". In addition to its format, there is support and other ".rar", ".zip", etc. It has a pretty simple and concise interface, but it does not make it less attractive, due to ease of use.
Like all the programs worked in this article work in Russian and with good speed.
Virtually a complete copy of Viryrr, both in appearance and functionality. Supports many types of archives and has an excellent compression ratio. The only negative minus is the inability to pack the file in the ".rar" format (only unpacking), but we hope that this omission will soon be fixed. Russian is included in the kit.
The file archiving method depends on the type of data being stored, from the convenience of their recovery, etc. If you look at the file properties or directory in WindowsExplorer, you will see the Archive attribute (archive). It indicates whether it is possible to archive this file / directory. If the attribute is enabled, the file / directory may need archiving. The main types of archiving are as follows:
Normal / complete archiving. All selected files are archived regardless of the archive attribute value, after archiving the file, the archive attribute is reset. If the file is then changed, the archive attribute is turned on, indicating that the file needs archiving.
Copy archiving. All selected files are archived regardless of the attribute value of the archive. In contrast to the usual archiving, the archive attribute does not change. This allows you to execute another type.
Difference archiving. Creates archive copies of files that have been changed since the last ordinary archival. The presence of an archive attribute indicates that the file has been modified. Only files with this attribute will be archived. But the archive attribute does not change. This allows you to execute another type.
Extreme archiving. Creates archive copies of files that have been changed since the last normal or extension. The archive attribute indicates that the file has been modified. Only files with this attribute will be archived. After archiving files, the archive attribute is reset. If the file has been changed, the archive attribute is turned on, showing that the file requires archiving.
Daily archiving. Save files changed over the past day. This type of archiving does not change file archive attributes. You can fulfill full archiving weekly and in addition to this daily, difference and add-on archiving. You can also create an extended archive set for monthly and quarterly archives that will include irregularly archived files. The advice happens, there are weeks and months before someone will find that the necessary file or data source disappeared. Therefore, planning monthly or quarterly archives, do not forget that you may need to restore and outdated data.
Difference and extension archiving
Currently, the best archiver for Windows is the WinRar archiver.
Winrar features:
· Winrar features:
Allows you to unpack the archives of CAB, ARJ, LZH, TAR, GZ, ACE, UUE, BZ2, JAR, ISO, and provides data archiving in Zip and Rar formats
Provides full support for the archives ZIP and RAR
It has special algorithms optimized for text and graphics. For multimedia compression can be used only with RAR formats
Supports drag and drop technology (Drag & Drop)
Has a command line interface
Can carry out continuous archiving, which provides a higher degree of compression compared to conventional compression methods, especially when packing a large number of small contents of the same type
Provides support for multi-volume archives, that is, it carries out a breakdown of the archive into several volumes (for example, to record a large archive on discs). Expanding volumes: RAR, R01, R02, etc. With a self-expanding archive, the first volume has an extension exe
Creates self-extracting archives (SFX) conventional and multi-volume archives, ensures their passwords
Provides restoration of physically damaged archives
Has a recovery tool to restore the missing parts of a multi-volume archive
Supports Unicode in file names
For beginners, the Wizard (Wizard) mode is designed, with which you can easily make all the operations on the archives.
WinRar has other additional features. WinRAR is able to create an archive in two different formats: RAR and ZIP. Consider the benefits of each format.
This article will present the typology of Russian archives, will demonstrate to whom they are subject to and what laws are governed, and what differ from each other.
Exist state Archives, Departmental Archives, Municipal Archivesand Non-state archives. The activities of all archives are governed by the Federal Law "On Archived In the Russian Federation", adopted in 2004. In addition, there are about 50 legislative acts relating to the archival sphere. Only archival documents that have passed the expertise of values \u200b\u200bare a document of the Archival Fund of the Russian Federation and are subject to constant storage. All archives are divided into those that may store documents of the Archival Foundation temporarily or constantly.
TO staterelate federal archives and archives of constituent entities of the Russian Federation - regional archives. And federal, and regional archives are divided into two subspecies: historical noncomplete archives and components of specialized archives.
There are only 15 federal archives. The federal archives are subject to Rosarhiva - the federal archival agency leading to the accounting of documents of the Archival Fund of the Russian Federation. Regional archives obey the regional administration, and Rosarhiv gives them recommendations as a methodical center. However, there is a double submission: it may be that the archive is subordinate not only to the regional, but also to the federal authorities. For the researcher, this is important because each stage of the manual can impose its restrictions on access to specific documents.
Municipal archives There are district and urban. Among them are archives of local self-government bodies and cooperative archives in which documents of local institutions, organizations, personal enterprises are stored.
Departmental archives It can be divided into three types: current archives of departments, current archives of agencies that are part of departmental systems and specialized sectoral departmental funds. Departmental archives are a structural division of the department to which belongs, and obey him directly. This means that they are free to allow and not allow access to documents at the discretion of the archive administration.
Departmental archives can only store documents temporarily or depository. After the expiration, the documents must be transferred to Rosarhiv, where their constant storage is carried out. The term and conditions of depositary storage are defined in the contract, which must be concluded between the departmental archive and Rosarhiv, but there is no information about these agreements.
Documents on mass repressions and declassified documents of the NKC-OGPU-NKVD-MGB-KGB, as well as archival criminal cases of rehabilitated and non-recharged citizens were created by the security authorities, the successor of which is currently the FSB, in the archives of which the vast majority of these cases are stored. Documeno is not confirmed if these documents are owned by Rosarhiva. The time storage period of such documents was determined by paragraphs 1 of Article 22 of the Law "On Archived" and is 15 years.
Non-state archives There may be a variety of, but you can allocate three main categories: archives of individuals, archives of privatized enterprises, institutions and organizations, and archives of public associations. The archives of public organizations include, for example, archives of political parties and religious organizations.
Each physical and legal person is entitled to create its own archives, but also it is responsible for the state and ensuring the safety of a valuable document. The main document determining the relationship between the owners of the non-state archive and the state archival service is an agreement in which the rights and obligations of each party are prescribed. For example, if the archive leader does not fulfill the obligations on the correct storage and use of particularly valuable documents - they may be withdrawn by the court decision. Non-state archives can store the documents of the Archival Foundation only temporarily.
The archive file is a set of one or more files placed in a compressed form in a single file from which they can be removed in the original form if necessary. The archive file contains a table of contents, allowing you to find out which files are contained in the archive. In the table of contents of the archive for each file contained in it, the following information is stored:
· File name;
· Information about the directory containing a file;
· Date and time of the last modification of the file;
· File size on disk and in archive;
· Cyclic control code for each file used to verify the integrity of the archive.
Self-extracting (SFX, from english Self-Extracting) Archive - This is an archive to which the executable module is attached, allowing you to retrieve files by simply starting the archive as a regular program. Thus, additional external programs are not required to extract the contents of the SFX archive. SFX-archives, like any other executable files, usually have extension .exe.
The SFX archives are convenient when you need to transfer someone to someone, but you are not sure that the addressee has an appropriate archiver for unpacking it. You can also use SFX archives to distribute your own programs.
Multi-volume archives (archives of several parts)- sequences of archive files (volumes). Toma - These are fragments of the archive consisting of several parts. Toms are usually used to save a large archive on several diskettes or other interchangeable media. Archival volumes do not allow subsequent addition, updates or delete files.
When creating a multi-volume archive in WinRar, the first volume in the sequence has the usual extension .Rar, and the expansion of subsequent volumes is numbered as. Cr00, .r01, R02, etc. Toms can also be continuous and self-extracting. The first self-extracting volume has another (i.e. non.Rar) expansion, for example, .exe for DOS or OS / 2 SFX volumes).
To unpack volumes, it is necessary to start extraction from the first volume (with the extension.rar). If the volumes are on a non-free medium (for example, on a hard disk), then you first need to write all the volumes into one folder.
In addition to creating the above archives type, the WinRar archiver allows you to create continuous (solid) archives.
Continuous archive - This RAR archive packed in a special way, in which all compressible files are considered as one data stream. Continuous archiving significantly increases compression ratio, especially when adding a significant number of small similar files. However, some shortcomings of continuous archiving should be taken into account:
Updating continuous archives is slower than the usual;
Encrypted continuous archives cannot be changed;
To extract one file from a continuous archive, you must analyze all previous archived files, so the extraction of individual files from the middle of the continuous archive is slower than extraction from the usual archive. However, if all or a few first files are retrieved from the continuous archive, in this case the velocity speed is almost equal to the velocity of the ordinary archive;
If any file is damaged in a continuous archive, it will not be possible to remove all files following after it. Therefore, when saving a continuous archive on an unreliable medium (for example, on a diskette), it is recommended to add information for recovery.
Continuous archives are better to use in cases where:
The archive is rarely updated;
No need to often extract one or more files from the archive;
The compression ratio is more important than the speed of compression.
Multi-volume and self-extracting archives may also be continuous.
Archiving, or file compression, is a special process providing for a decrease in the amount of free space on the drive that the file occupies. To date, there is a sufficiently large variety of special utilities for data compression. However, many do not even understand what is an archive. What is the archive and archiving, we will consider in this article.
Immediately it is worth noting that the article is about computer archives, and not about departmental or any other. The departmental archive is a topic for a separate article, as it has nothing to do with virtual.
What is the archive?
Many people do not even know what the advantages are the process in question. For those who are wondering: "Archive - what is and why is it needed?" - There is quite simple explanation.
The archive is a peculiar analogue of the folder in which several files are stored. However, in order to open these files or copy them to any other folder, you initially need to be rolled. What happens sometimes quite a large amount of time. It is worth noting that the time it takes to extract files from a specific archive directly depends on exactly how the correction is made as a powerful computer, as well as the files of which volume will be removed.
Why archive?
An increase in the available amount of data is the main purpose that the archive contains. What is the amount of data and how important it is for modern users, it is unlikely to explain to someone. After all, even the continuous development of modern drives and all sorts does not allow to satisfy the needs of many people.
The second destination of the archive is to simplify today not all the Internet has a sufficiently high speed for quick file transfer, so their volume is of great importance. Given the fact that in most cases, information is pumped through specialized file sharing, to broadcast files from one computer to another downe time. First to download to the exchanger, and then for download directly to the user's computer.
That is why it is much easier to transmit files, preloading them into a standard archive. What is the archive, already mentioned above.
How to achieve?
To date, there is no difficulty in finding specialized archivers, each of which is characterized by its set of features. Some include only basic functions, while others provide more features, including checking files to all sorts of viruses or the ability to view information of various types, without removing it from the archive. It is worth noting that a fairly large number of programs offers the user to choose a specific compression ratio, forming the so-called self-extracting archives.
The most common variants of archives today are considered to be such as Zip and RAR. Such archivers are initially installed almost all computers and are actively developing.
Extraction of data and their archiving
The user has the ability to fully independently select the name for its future archive, as well as determine which it is better to use the expansion and method of compression. The archive contains a specific number of files and various folders, and for unpacking it will be necessary to simply specify the path to the folder in which it will be extracted. As mentioned above, in some modern programs it is possible to preview certain files in read-only mode.
Recently, such a specialized function is used to be widespread as creating self-extracting archives. A self-expanding file archive is a specialized type that allows you to retrieve files without using any additional utilities. After all, today, archivers are not installed on all computers, so it is necessary to somehow provide the ability to extract information to such users. By itself, this option is a standard file.exe, which includes directly encrypted data, as well as a special installation module.
How to restore the archives after damage?
The archive of documents is far from the safest storage option of a large since due to certain reasons such a situation may occur that it will damage and extract files from it will not be possible. In the predominant, most cases, such problems arise due to the fact that in the process of downloading the archive, the user has disappeared and the archive has disappeared due to the influence of a standard viral program.
Modern developers were able to exit such a situation by using a special function "Leave damaged files on disk", as well as another additional feature - "Add information for recovery". Thus, it is possible to significantly increase the chances of the fact that ultimately unpacking the archive will be successful and the user will have the opportunity to use the data they need.
How to protect yourself from unauthorized access?
Another useful and fairly popular function is to use passwords that allow you to protect the archive from prying eyes, eliminating the possibility of viewing it. It will not be possible to also unpack it, providing effective protection for confidential and commercial information. Thus, you can archive certain data not only in order to reduce their volume or simplify transportation, but also to hide them from strange eyes. It is especially recommended to do this to those people who store important on the work computer when there is a risk that someone else can see it.
Continuous archive
Among other things, a particular attention should be paid to such a type as a continuous archive. The continuous archive in the computer is a set of files that represent a consistent flow of information. In this case, an order of magnitude increases, but the update, as well as the subsequent unpacking of the archive, is carried out within a longer time. And you need to understand correctly that if one of the files in such an archive will receive any damage, then in this case there will be no possibility of restoring information. It is for this reason that it is best to archive in such a way that the information can ultimately be restored.
Thus, continuous archiving is rarely used by modern companies. The organization's archive is first of all a secure information repository that will be protected from accidental removal, as well as prying eyes, so use in this role a continuous archive, which may end up completely destroying files, is far from the best option.