7-Zip File Manager
7-zip File Manager is an open-sourced GUI application that is primarily used to archive and un-archive a wide variety of file formats. The software uses its own proprietary 7z file format, but it is more than capable of reading from and writing to a handful of other widely popular archive formats. While 7-zip comes with a graphical interface for typical users, it is actually designed as a command-line interface, and it can be invoked by the command “p2zip,” or even via integrated functionality within Windows’ right-click menus. Development of 7-zip started in the late 90s and is still in development to this day by the same author: Igor Pavlov. Additionally, 7-zip is open source, meaning that the code is publicly available to anyone who wishes to read it, and best of all, it is protected under the GNU General Public License, with the exception of the code that is used to support extracting the popular RAR file format, as it is protected by copyright, yet given a special restriction to allow redistribution.
Supported Archive Formats
Obviously, 7-zip File Manager supports the 7z archive format with both compression and decompression capabilities. These archives are incredibly powerful, and can store thousands of directories and files in each. Much like other containers, the size is significantly reduced. However, the method used to accomplish this is a bit unique: 7-zip uses a group of filters and other compressions to maximize reduction of the output file. These filters can be anything from encryption algorithms to preprocessors to other compression algorithms, and each works together to minimize file size.
At its very core, the 7-zip proprietary compression uses other well-known lossless codecs to perform its archive tasks; notably bzip2, LZMA, and PPMd. LZMA is a compression developed by 7-zip author Igor Pavlov himself, as well as the newest player in 7-zip File Manager’s arsenal. The LZMA compression uses what is called a “sliding dictionary” to reduce file sizes in common patterns of bits, and with a supported dictionary size of up to four gigabytes, it is very powerful indeed. Lastly, the 7z archive file format is public and is easily modified, making it a great solution for many purposes.
Testing has found that the 7z archive format is up to 17% more effective than the traditional ZIP archive, but this efficiency is highly dependent on the data that is being archived. Data with lots of repeating patterns can be archived at up to 30-70% smaller than traditional formats or as low as 2-10% smaller.
While 7z is the primary compression architecture used in 7-zip File Manager, that isn’t to say that it doesn’t support other popular formats as a stand alone. 7-zip allows both packing and unpacking of ZIP, GZIP, TAR, WIM, bzip2, and other popular formats. Then, while it doesn’t allow the creation of such archives, it has no problem with uncompressing popular formats such as APM, ARJ, CHM, cpio, DEB, FLV, JAR, LHA/LZH, LZMA, MSLZ, Office Open XML, onepkg, RAR, RPM, smzip, SWF, XAR, CramFS, DMG, FAT, HFS, ISO…. the list goes on for a while. The point is this: you’ll likely never find a valid archive format that 7-zip is unable to at least open.
Some programs are packaged as MSI installers. And some of these installers can even be unpacked by 7-zip! This allows users to access the files included in the installer. Also, some CAB and NSIS files can be unarchived with this software. 7-zip can even unpack some EXE files that are self-extracting or include packed files.
When dealing with ZIP files, 7-zip uses a unique encoding method that makes end-result files smaller but encodes at a lower speed. It is a trade-off, so depending on what you are trying to do, you may want to go with another solution if speed is an issue.
7-zip has support for a 256-bit AES cipher for archive file encryption and security, and it can be applied to both the 7z container base file system as well as the file system itself. This encryption is in the form of a password that users must enter to decrypt the volume into its normal state. WinZip has its own form of AES encryption that 7-zip both supports and allows users to select when archiving files. It does not, however, allow filename encryption like the 7z format does.
When compressing files with 7zip, you can specify a a dynamic file size for a volume. This makes it really easy to make backups of physical media, such as CDs, DVDs, and other portable mediums of storage that can be read by the computer.
The 7-zip GUI features a 2-panel file manager that allows for easy navigation of both the local and archive file system. This allows for easy extraction and addition of files to archives. This layout format is similar to that which is found in FileZilla FTP.
When working with compression and decompression, 7-zip supports multi threading on multi-core processors. This allows for much faster packing and unpacking of archive files, saving time while also maximizing efficiency of the compression.
A notable feature in 7-zip is the ability to open some binary files such as EXE, MSI, CAB, and NSIS. This allows users to decompress the data that is stored in executables that serve as program setups, installers, and self-extracting programs without having to launch the program itself. This can help avoid viruses that can come bundled with such programs.
Sometimes, you will encounter an archive with corrupt filenames or structures. 7-zip is powerful enough to repair these damaged filenames and file systems to allow the contents to be extracted, even when the file hierarchy is damaged.
You can also create self-expanding EXE files with 7-zip. This allows you to store large volumes in a single EXE file, which when run unpacks to the specified folder. It is fast, lightweight, and portable.
7-zip features a graphical user interface, often unique to the operating system that it runs on. On windows, the GUI looks similar to a combination of WinRAR and FileFilla FTP, but p7zip appears to have the GUI of a Linux Archive Manager.