Part One: Key features at a glance
The advantages of WinRAR over other data compressing and archiving tools
We asked several editors why they liked WinRAR. The answers varied from, “It’s the best data
compressor” and, “The Recovery Records are just very practical” to, “If someone asks me about a data
compressor, I simply say: ‘Use WinRAR, that’s a good one.’” In this article, we will point out the
advantages WinRAR has over other compressing tools and give a short description of its key features.
“Besides its high technical standards, WinRAR stands out due to a user‐friendly licensing policy, an
extensive test phase and its excellent customer support. WinRAR further offers uniform format support,”
says Öncül Kaya, Managing Director of win.rar GmbH. “With every new version, WinRAR adds new
compression methods to the ZIP format which are not part of the ZIP 2.0 standard. Often these updates
are unsupported by the previous version.”
Some background facts: The inventor of the RAR format
The RAR algorithm, which forms the basis for the RAR archiver WinRAR, was invented by the Russian
programmer Alexander Roshal. Besides the RAR format, WinRAR supports several non‐RAR formats such
as 7Z, ACE, ARJ, BZ2, CAB, GZ, ISO, JAR, LZH, TAR, UUE, Z and the ZIP format as well, thus offering the
highest compatibility possible.
WinRAR is the 32‐bit Windows version of the RAR archiver (with native 64‐bit support since version
3.90), and is also available for Linux, FreeBSD, DOS, OS/2 and Mac OS X operating systems. For Windows
systems, the data compressor is available either as a command‐line interface (Rar.exe) or with a
graphical user interface (WinRAR.exe).
Compressing large archives effectively: Solid archives
The RAR format offers a very high compression rate, especially when using ‘solid archiving’, which
handles many small but similar files together as a single data stream and compresses them into a single
file. Less redundancy means a higher compression rate, but also results in a lower compression speed –
especially when unpacking individual parts of the RAR archive. If the user wishes to create an archive
which will rarely be renewed and will only be unpacked as a whole, and considers the compression rate
more important than the compression speed, then solid archives is the right choice.
Splitting large archives into several files: Split archives (Multivolume files)
Another important feature is the support of ‘split archives’ (multivolume files). Volumes are individual
parts of a split archive. They allow the user to save large archives on multiple discs or other removable
media. Volumes may also be solid or self‐extracting. The first self‐extracting volume has a different file
extension (other than .rar), e.g. .exe for Windows SFX volumes.
Protecting archives from destruction: Recovery Records
The RAR format also has several features which are missing from the ZIP format, such as Recovery
Records – which allow the user to repair archives saved on damaged data‐storage media.
The RAR archive format supports a special kind of redundant information known as Recovery Records. If
an archive has a Recovery Record, it can be repaired even after having been damaged due to a defect on
a disc or other data loss. The ZIP format does not support Recovery Records.
The Recovery Record contains up to 524,288 Recovery Sectors. If the data is damaged continuously then
each Recovery Sector is capable of recovering 512 bytes of damaged data. This value may be lower if
several areas are damaged.
Archives for everyone: Self‐extracting archives (SFX ‐ SelF‐eXtracting archive)
A self‐extracting or SFX (SelF‐eXtracting) archive is an archive which is merged with an executable
module. This module is used to unpack files within an archive when the SFX archive is executed. This is
why no external program is needed to unpack the contents of an SFX archive; it will execute by itself.
Nevertheless, WinRAR is able to handle SFX archives like any other archive. If a user prefers not to
execute a received SFX archive (due to possible viruses, for example), WinRAR is able to simply view or
unpack the contents of the archive.
SFX archives are useful if a user would like to pass an archive on to somebody without knowing whether
this person has access to a program for extracting archives. For the user’s convenience, the SFX archive
further extracts the files to the right location. Software producers may also use SFX archives to distribute
their own software. The WinRAR installation, for example, is an SFX archive which is based on the GUI
RAR SFX module Default.sfx.
Protecting your archive from unintended modifications: Locking archives
Another advantage of the RAR format is the possibility to lock important archives in order to protect
them from unintended modifications.
The RAR format supports a locking feature for archives. Locked archives can no longer be modified by
WinRAR. Locking important archives can help prevent accidental changes to your archives.
Transforming archives into another packing format: Converting archives
WinRAR’s command ‘Convert archives’ allows for the recompression of archives from one format to
another. Depending on the mode, the user can either select several files or directories to convert, or only
convert the current archive. All file types supported by WinRAR can be converted to RAR or ZIP formats.
Some advantages illustrating this feature:
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Better compression
This feature is very useful if a user wishes a significantly better compression for an archive: For example,
if the user is using a Standard ZIP 2.0 archive, recompressing it into an RAR archive would be the most
suitable thing to do. RAR compresses more effectively than Standard ZIP 2.0.
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A uniform archive format
Many users wish to use a uniform archive format (RAR) on their computer, instead of many different
types such as CAB, ARJ, LZH, TAR, GZ, ACE, UUE, BZ2, JAR, 7Z or Z archives.
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Standardized compressing options
The conversion feature is very useful for providing several archives with a single password, to switch
from non‐solid to solid compression or to simply repack all archives with better options.
Whether considering solid archiving, split archives or Recovery Records: this article offers you an
overview of the benefits of the RAR format and the data compressing and archiving tool WinRAR. But
this is just the beginning: In a series of articles, we will provide you with a detailed step‐by‐step
presentation of all of WinRAR’s important features. You will be amazed by the features WinRAR has to
offer.