Archive formats. How to compress a file as much as possible in WinRAR
We are so designed that every time we need to create an archive, we ask ourselves again and again: what is better to choose: a RAR or ZIP archive? Any modern archiver must be able to create RAR and ZIP archives. It is not enough to say that these are the two most popular archival formats; it is absolutely necessary to clearly distinguish between their features and advantages. This is what we will talk about next.
ZIP Archives
The main advantage of archives in ZIP format is its prevalence. Thanks to Windows is huge number of archives on the Internet use the ZIP format. This does not mean at all that this format and data compression algorithm are the best. It’s just that it’s probably available, so when you’re going to send someone an archive with data, but you’re not at all sure that your recipient will be able to use the WinRAR program, or another that can work with RAR archives, then it probably makes sense to use archive in ZIP format. However, this problem can be solved completely radical method, – use a self-extracting SFX archive. Even though such archives are a little larger in size, you don’t need anything to unpack the SFX archive.
RAR archives
The RAR format is definitely superior to ZIP in the main thing: the work of programs with RAR archives is more stable, and the archiving algorithm in the RAR format allows you to get more high degree data compression. The advantages of RAR are especially noticeable when creating continuous and multi-volume archives. Archives in RAR format have a wider range of functions, such as: recovery damaged archives, self-extracting volumes, blocking accidental file modifications, and many others. Both archiving formats can work with files of almost any size ( maximum size file 8589934591 GB), and have the ability to comment on files included in the archive.
Archive comment
By the way, you can include various text comments in ZIP and RAR archives. Usually, they are called that: archive comments. In some cases this can be very convenient. In order to add your comments to an already created archive, you can use graphical shell WinRAR or command line. Whoever likes it more. In the first case, you need to use the “Add comment” option, and in the second case, use the “z” command<файл>" And, in addition, it is convenient to create comments during the process of archiving files, using the dialog box of the WinRAR section “Archive name and parameters”. Thus, if you, for example, open an archive with comments in WinRAR, then in the list of archive files, to the right about them, comments will be visible. The size of the comment window can be easily changed by simply dragging the left edge of the window with the mouse.
Considering that WinRAR works easily and freely with ZIP archives, ZIP archivers RAR don’t understand, the choice is obvious - only WinRAR.
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Often in Everyday life there is a need to compress files for the convenience of storing them, recording them on media and quickly exchanging them via social media, e-mail , file hosting services and other services in global network Internet. However, not all files are equally compressible. Files are compressed best text format(txt, doc). Archive files (rar, zip, 7z, lha, tar, gz, jar, etc.), video (avi, mpeg, wmv, flv), music (mp3, wma, aac) and images (jpeg, jpg, gif , png) are slightly reduced in size because they are initially compressed files. This also includes Microsoft files Office with docx extensions,xlsx.
Specialized archiver programs, the most famous of which are WinRAR, 7zip and WinZip, compress (reduce the size) of files. We’ll talk about how to compress a file as much as possible in the WinRAR archiver.
To start packing files into an archive, your computer must have WinRAR archiver installed. To start the compression (archiving) operation, you need to select the files that you are going to compress. Then clicking right click mouse over the selected area, call up the context menu, in which we select the line “Add to archive...”.
In the “Archive name and parameters” working window that appears, on the “General” tab, set the name of the future archive, and also select the format and compression method. For formats, we recommend choosing the publicly available ZIP format, since some OS have difficulty reading the RAR format. In the “Compression method” drop-down menu, select “Maximum” accordingly. Click OK.
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To set your own compression settings for the RAR format, go to the “Advanced” tab and click on the “Compression Options” button in the “ group NTFS Settings" In the new dialog box, you can select specific parameters for text, audio and full-color graphics compression, select the main compression algorithm, etc.
For adding a new file to an existing archive with maximum compression, you need to open this archive and select the line “Add file to archive” in the “Commands” menu; Even easier, you can drag the desired file into the program window. This will automatically open a new Archive Name and Options dialog box. All you have to do is set the compression method to “Maximum” for the new file and click on the OK button.
I think reading the article did you good. Now questions about maximum compression in WinRar are a thing of the past, and if they arise or are forgotten, then in recovery computer knowledge our website will help!
Dozens of archivers are popular on the Internet today, and in the description of each program you can find that its algorithm is the very best... I decided to take several popular archivers on the Internet, namely: WinRar, WinUha, WinZip, KGB archiver, 7Z and test them in “combat” » conditions.
A little preface... The comparison may not be very objective. Comparison of ahivators was carried out on the most common home computer, the average for today. Besides, they didn’t take it Various types data: compression comparison was carried out on a regular Word document, of which many who study or work with them can accumulate great amount. Well, it is logical that it is advisable to pack information that you rarely use into an archive and sometimes extract it. And it’s much easier to transfer such a file: it will be copied to a flash drive faster than a bunch of small files, and it will be downloaded faster over the Internet...
Compression comparison table
For a small experiment, a relatively large file RTF is about 3.5 MB and is compressed by various archivers. We are not taking into account the operating time yet, the features of the programs will be discussed further, but now we will just look at the compression level.
| Program | Format | Compression ratio | Size, kbytes | How many times has the file size decreased? ? |
| KGB Archiver 2 | .kgb | maximum | 141411 | 22,99 |
| WinRar | .rar | maximum | 190546 | 17,07 |
| WinUha | .uha | maximum | 214294 | 15,17 |
| 7Z | .7z | maximum | 218511 | 14,88 |
| WinZip | .zip | maximum | 299108 | 10,87 |
| Original file | .rtf | Without compression | 3252107 | 1 |
As can be seen from the small plate, the highest compression ratio is achieved with KGB programs Archiver 2 - decreased by 23 times original size file! Those. if you have several gigabytes of various documentation on your hard drive that you don’t use and want to delete (but you can’t shake the feeling that it might come in handy) - wouldn’t it be easier to compress it with such a program and write it to disk...
But about all the pitfalls in order...
KGB Archiver 2
In general, it’s not a bad archiver; according to the developers, their compression algorithm is one of the “strongest”. It's hard to disagree...
Only the compression speed leaves much to be desired. For example, the file in the example (about 3 MB) was compressed by the program for about 3 minutes! It is not difficult to estimate that she will compress one CD disc for half a day, if not more.
But this is not particularly surprising. Unpacking a file takes as long as compression! Those. If you spent half a day compressing some of your documents, then you will spend the same amount of time getting them out of the archive.
Result: the program can be used for small volumes information, especially when it is important minimum size source file (for example, the file needs to be placed on a floppy disk or on a small flash drive). But again, guess the size in advance compressed file You can’t, and perhaps you’ll waste your time on compression...
WinRar
The famous program in the post-Soviet space is installed on most computers. Probably, if she had not shown such good results, she would not have had so many fans. Below is a screenshot showing the compression settings, nothing special, except that the compression level was set to maximum.
Surprisingly, WinRar compressed the file in a few seconds, and the file size was reduced by 17 times. a very worthy result, considering that the time spent on processing is negligible. And the time to unpack the file is even less!
Result: great program, featuring some of the most best results. During the compression settings, you can also specify the maximum archive size and the program will split it into several parts. This is very convenient for transferring a file from one computer to another on a flash drive or CD/DVD disk, when you cannot write the entire file to...
WinUha
A relatively young archivist. It cannot be called super-popular, but many users who often work with archives have an interest in it. And it’s no coincidence, because according to the developers of the archiver, its compression algorithm is stronger than that of RAR and 7Z.
In our small experiment, I would not say that this is so. It is possible that on some other data it will show much better results...
By the way, when installing, select English language, in Russian - the program displays “kryakozabry”.
Result: not a bad program with an interesting compression algorithm. The time to process and create an archive is, of course, longer than WinRar, but for some types of data you can get a slightly higher compression ratio. Although, personally, I would not put much emphasis on this...
7Z
Very popular free archiver. Many argue that the compression ratio in 7z is even better than in WinRar. It is quite possible, but when compressed with the “Ultra” level on most files, it loses to WinRar.
Result: a good alternative to WinRar. Quite comparable compression ratio, good support Russian language, convenient integration into the Explorer context menu.
WinZip
Legendary, one of the most popular archivers ever. On the Internet, probably the most common archives are “ZIP”. And it’s no coincidence - despite the not-so-high compression ratio, the speed of operation is simply amazing. For example, Windows opens such archives as regular folders!
In addition, we should not forget that this archiver and compression format is much older than its newfangled competitors. And not everyone has them now powerful computers, which will allow you to quickly work with new formats. And the Zip format is supported by all modern archivers!
V. KOROTKOV, programmer
BEGINNER USER SCHOOL
When working on personal computer Quite often there is a need to reduce the file size in order to save disk space. For example, you need to transfer files from one computer to another on floppy disks. Or do you need to send a large file via e-mail- By reducing its size, you can save both time and money. The best decision in such cases - create a so-called archive file, or, more simply put, archive. This is a single file in which one or more source files are compressed for compact storage of information.
Designed for working with archives special programs which are called archivists. Using archivers, you can pack files into archives and unpack them, as well as view the contents of archives. Packing files into an archive is called archiving or archiving, and their extraction - unzipping.
Exist different formats archives: ZIP, ARJ, RAR, CAB, TAR, LZH, etc. When an archive file is created, it is assigned an extension that matches the archive format. For example, a file named MyDoc.zip is a ZIP archive. The format affects the efficiency of file compression; for example, a RAR format archive takes up less disk space than a ZIP format archive containing the same source files. In addition, efficiency depends on the type of files packed into the archive. Image files with the BMP extension Microsoft documents Word can be compressed two to four times, text files- approximately twice. Executable files (with the EXE extension) are slightly less susceptible to compression, and graphic files, having a TIF extension, are practically not compressed.
Almost all modern archiving programs for Windows allow you to work with archives various formats. The principles of managing these programs are largely similar.
ARCHIVERS WINRARIt is convenient to consider the techniques of working with archivers using the WinRAR program as an example. This program has great capabilities. We will try to list those that may be useful to a novice user. WinRAR allows you to create archives in two formats - RAR and ZIP. In addition, it supports basic operations (unpacking, viewing contents) with archives of other formats: CAB, ARJ, LZH, TAR, GZ, ACE, UUE.
VIEWING ARCHIVE CONTENTS
Run the WinRAR program, for example, with the command Start - Programs - WinRAR - WnRAR. When launched, the main program window is displayed. By selecting the archive file in this window and clicking the button View in the toolbar, you can see what is in the archive (1).
You can evaluate how efficiently a particular file is compressed by comparing the numbers in the columns Size And Compressed. With files located in the archive, WinRAR program can perform any actions: view them, make changes to them, launch executable files (having EXE extension, COM, BAT). In this case, WinRAR will take care of the unpacking itself. necessary files to a temporary folder, which will be automatically deleted when the program ends. In the same window you can delete files from the archive and add new ones.
To add files, click the button in the toolbar Add, in the dialog box that appears, select necessary files and close the dialog box with the button OK.
To delete files contained in the archive, select them and click the button in the toolbar Delete ( or key Delete on keyboard). Before deleting files, WinRAR asks for confirmation.
CREATING AN ARCHIVE
Select the required files. It is convenient to select a group of files with the mouse while holding down Ctrl key. Pressing Ctrl+A selects all files displayed in the window. You can also use the corresponding menu items File. Click the button Add in the toolbar (or keyboard shortcut Alt+A). A window will appear Archive name and parameters(2). In this window you should enter full name the created archive file. For this it is convenient to use dialog box Archive Search, which is called by pressing a button Review. In the window Archive name and parameters you can also select the format created archive: RAR or ZIP. The default format is RAR, and in most cases there is no need to change it, as it provides significantly better compression than ZIP. If you are going to transfer the archive to another user, ask if they have an archiver that supports this format.
When to save large archive on floppy disks, you have to create multi-volume archive, i.e. consisting of several parts called volumes. Each volume is a separate file. If you want to create such an archive, in the field Volume size select option 1475500 (this is the size of a three-inch floppy disk). It is also recommended to check the box Recovery information. This is necessary so that the archive can be restored in case of data corruption, since a floppy disk is an unreliable storage medium. It is convenient to create a multi-volume archive on a hard drive, and subsequently copy the volumes to floppy disks. Before creating a multi-volume archive, consider one important limitation: it does not allow changes, that is, the files contained in it cannot be changed or deleted, nor can they be added. If the user nevertheless tries to make changes to a multi-volume archive, a window appears on the screen informing them that this operation is impossible.
If you are going to transfer an archive to another user, but are not sure that he has the appropriate archiver, you can create self-extracting archive. To do this you need to check the box create SFX archive(SFX - from the English SelF eXtractor). This archive is executable file, it has an .EXE extension, and an archiver is not needed to unpack it. A self-extracting archive takes up more disk space than a regular archive. A multi-volume archive can also be self-extracting.
Once you have set the necessary parameters on the tab Are common, it is advisable to go to the tab Files(3).
Make sure that the names of all the files you want to archive are in the Added files. If this is not the case, use the special dialog box that is called up by the button Add.
Click the button OK, and the program will begin creating an archive. At the same time, a special indicator appears on the screen informing the user about the archiving process.
UNPACKING THE ARCHIVE
You can unpack the entire archive, or you can only unpack separate files contained in it. In the first case, you need to select the archived file, in the second, go to archive viewing mode using the button View and then select the required files. Click the button on the toolbar Extract to(or key combination Alt+E), a window will appear Extraction path and parameters(4), if necessary, you can specify the folder in which the unpacked files will be saved. By default, the folder in which the archive is located is specified. Click the button OK, and the program will begin to unzip the files.
The easiest way is with a self-extracting archive. It needs to be launched from Windows Explorer, How regular program, a dialog box will appear in which you should specify the folder intended for saving files (5).
But what if you need to view the contents of an SFX archive or extract not all files, but only some of them? WinRAR allows you to work with a self-extracting archive in the same way as with any other.
It will be more convenient to unpack a multi-volume archive if you first copy all volumes to HDD in one folder. If you do not do this, then, after finishing unpacking the next volume, the archiver will display a dialog box asking you to specify the full name next volume. You need to start unpacking from the first volume, its name (if it is a RAR format archive) is either “volume_name.part01.rar” or “volume_name.r00”. The first volume of a multi-volume SFX archive has the extension .EXE.
MASTER
Wizard mode (6) appeared in WinRAR 3rd version. The wizard is called by the button of the same name in the toolbar. Designed for first-time users, it makes basic archiving and unzipping operations extremely easy with a simple step-by-step procedure.
ARCHIVERS WINZIPAnother popular archiver program for Windows. Focused primarily on working with archives in ZIP format. The main window of the program resembles the WinRAR window, but the methods of working with these two archivers are somewhat different.
VIEW ARCHIVE.
EXTRACT AND DELETE FILES
First, you need to open the archive, to do this, click the button Open in the toolbar. You can also use the keyboard shortcut Ctrl+O. In the dialog that appears, select the archive file and click the button OK. A list of archive contents will be displayed in the main window (7).
If you want to view a file, select it and click the button View. The program that is associated with this file type will be launched. The same result can be achieved double click by file icon.
If you need to delete files from the archive, select them and press the key Delete, in the next dialog box, confirm the deletion.
Before unpacking the archive, decide whether you are going to extract all the files or just some of them. In the second case, the necessary files should be selected. In the toolbar, click the button Extract, a dialog box (8) will appear in which you need to specify the folder to place the objects extracted from the archive. Close this window by clicking the button Extract.
CREATING AN ARCHIVE IN WINZIP
Copy all files to be archived to separate folder on your hard drive. Click the button New, a dialog box will open New archive (9).
Select the folder where the archive file will be placed. If you need a multi-volume archive, please note that it can only be created on floppy disks - unlike WinRAR WinZIP does not allow you to save such an archive on your hard drive. In field File name enter a name for the archive. Make sure the checkbox is checked Add dialog(this is necessary for further determination of the archived files). Close the window with the button OK.
In the next dialog box, the user must select the folder containing the source files. In field File name The default mask is "*.*". This means that the archive will include all files contained in the selected folder. If this option does not suit you, select the desired files by clicking the mouse while pressing the key Ctrl.
If you are creating a multi-volume archive, expand the list Multiple disk spanning(Split into multiple disks) and mark the position Automatic(Automatic). WinZIP assigns the same name to all volumes, so it is advisable to put numbers on the floppy disk labels.
Click the button Add in the dialog box. The main program window will display the contents of the newly created archive (if it is not a multi-volume archive). When a multi-volume archive is created, the program from time to time displays a window (10), requiring you to replace the floppy disk in the drive. If there are already some files on the floppy disk that you want to delete before writing the next volume, check the Erase any existing files on the new disk before continuing. Replace the floppy disk and press OK.
A regular archive file with ZIP extension can be converted into a self-extracting archive. To do this, open the archive in the main program window. Enter the menu Actions and run the command Make. exe file , after which a dialog box (11) will appear. The Default "UnZip To" folder field (unzipping folder selected by default) is optional. If left blank, the folder will be selected C:\Windows\Temp. Click the button OK, the program will create an SFX archive and offer to test it. Testing here means simple unpacking: you can check the newly created archive “in action”. If you want to perform this check, select Yes, Another window will appear in which you should click the button Unzip. Otherwise, click the button No.
INTEGRATION WITH WINDOWS EXPLORERYou can create and unpack archives in the Explorer or My Computer window using the context menu. For example, if WinRAR is installed on your computer, then by right-clicking on the archive file icon, you will see the following options:
Extract files - unpacking the archive into a random folder;
Extract to folder_name\ - a folder with this name will be specified in the current folder, and the contents of the archive will be unpacked into it.
To create an archive, in context menu file (or folder, or group of files), select one of the following:
Add to archive... - packing files into an archive with an arbitrary name;
Add to "archive_name.rar"- creating a RAR archive with the given name in the current folder.
DRAG-AND-DROP SUPPORTThe vast majority of programs for Windows support Drag-and-Drop technology (move and put), and archivers are no exception. To verify this, do an “experiment”. Start the archiver in archive viewing mode. Open the window My computer, and in it - some folder, for example My Documents. Place both windows so that each takes up about half the screen and does not cover the other. Place the cursor on the icon of one of the files contained in the archive, click left button mouse and, without releasing it, move the cursor into the window My computer. Now release the button. The file extracted from the archive will appear in the folder whose contents are shown in the window My computer. Similarly, “drag” some file from the window My computer into the archiver window. The archiver will display a dialog box asking if you are really about to change the contents of the archive. If you answer yes, a new file will be added to the archive.
Note. Depending on which versions of the mentioned archivers are installed on your computer, the same commands may be indicated in both Russian and English.
limitations in file systems
Each file system supports a maximum volume size, archive size, and number of archives per volume. For example, in general FAT16 and FAT32 volumes are limited to 4 GB and 32 GB (in general), respectively. There are some limitations related to FAT file systems you should know, given below:
FAT12: FAT mb is less than 16 volumes and is little formatted like FAT12. It is the oldest FAT type and uses 12-bit binary to hold group numbers. A formatted volume using FAT12 can hold a maximum of 4,086 groups, which is equal to 2 by 12 minus a few reserved values to be used in SALE. (we will discuss it in detail in the logical disk structure given later in this chapter). Therefore FAT12 is most suitable for smaller volumes. It is used on a Floppy Disk and there are about 16 mb hard disk partitions less than that.
FAT16: FAT16 uses a sixteen-bit binary number to hold group numbers. A volume using FAT16 can hold a maximum of 65,526 groups, which is equal to 2 by 16 minus a few reserved values to be used in SALE. (we will discuss it in detail in the logical disk structure given later in this chapter). FAT16 is used for hard disk volumes ranging in size from 16 mb to 2,048 mb. FAT16 volumes larger than 2 GB are not accessible from computers running MS-DOS, Windows 95/98/ME and many other operating systems. This limitation occurs because these operating systems Does not support group sizes greater than 32 kb, which results in a limit of 2 gb. (See groups limit given later in this chapter).
FAT32: In theory, maximum FAT32 volumes can be up to 2048 GB (approximately 2 terabytes). FAT32 is supported by OEM SR2 release of Windows 9, as well as Windows 98/ME. FAT32 uses a 28-bit binary group number (remember! not 32, because 4 of the 32 bits are "reserved"). Thus theoretically FAT32 can handle volumes with over 268 million groups (actually 268,435,456 groups), and will support drives up to 2 TB in size. However to do this the size of FAT grows very large. (we are going to discuss it in the topics given next in this chapter).
A comparison of the FAT types was then given in a table.
File system |
FAT12 |
FAT16 |
|
Used For… |
Floppy disks and small hard disk volumes |
Small to large hard disk volumes |
Medium to very large hard disk volumes |
Size of each FAT entry |
12 bits |
16 Bits (2 Bytes) |
32 Bits (4 Bytes) |
Maximum number of groups |
~268,435,456 |
||
Group Size Used |
0.5 KiB to 4 KiB |
2 KiB to 64 KiB |
4 KiB to 32 KiB |
Maximum Volume Size |
16.736.256 bytes |
2,199,023,255,552 bytes (about 2 2 41 terabytes or bytes) |
|
Maximum Archive Size |
After that 16MB (approximate) |
2,147,483,520 bytes |
4.294.967.295 bytes (2 32 – 1) |
Maximum files and directories within the root directory |
(128 for 3½ 1.44MB FDD and 512 for hard drive disk) |
|
(Long archive names may reduce the number of archives and directories available in the root directory.) |
.NTFS: NTFS stands for a new technology file system. It is used Windows 2000/HP. In theory, the maximum NTFS partition size is (2 from 64 to 1) bind.
Detailed description systems NTFS files outside the scope of this book however some limitations of it have been given in the following table:
Group
The smallest block of space on a hard disk for distribution that any software can access is a sector that contains 512 bytes. It is possible to have a distribution system for the disk where each file is assigned as many individual sectors as it is. For example, 1 mb file would require approximately 2,048 individual sites to store their data.
In the case of a FAT file system or rather we can say in most of the file systems, individual sectors are not used. There are several presentation reasons for this. When dos writes some information onto a hard disk, it doesn't allocate space wise, instead it uses new block group called storage.
FAT was designed many years ago and is simply a file system, and is not capable of managing individual sectors. What SALO does instead is to group sites into larger blocks called groups or distribution blocks.
A group is the smallest block of disk space that can be allocated to a file. This is the reason that groups are often called distribution blocks. It can be very difficult to manage the disk when the files are broken in the 512-byte portion.
A 20 GB disk volume using 512 bytes managed individually would contain over 41 million individual sectors, and keeping track of these many pieces of information would consume time and resources. However some operating systems allocate space to files by sector but they require some advanced information to do this correctly.
Groups are a minimal space allocated dos any information on the disk. Even storing only one byte long data on a disk requires a minimum of one group area on the disk surface.
If one group can store 512 bytes of information then to store 513 bytes, you will require 2 groups. Each archive must be assigned to the group integer number. This means that if the volume is using groups that contain 4,096 bytes then a 610 byte file will use one group so 4,096 bytes on the disk uses but 4,097 byte files are two groups thus 8,192 bytes on the disk.
This is the reason that cluster size is so important to make you confident of increasing effective disk use. Thus we can understand that a larger group size results in more wasted space.
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