77Zip is a free archiving utility with support for most popular archive formats, especially at the unpacking side. These include 7z, ZIP, RAR, CAB, ARJ, and ISO, to name but a few. It offers you a long list of customizable parameters, giving you full control how the archives are created, compressed, and packed.
Though 7z seems to be the star archive format among those supported, you will also find other well-established file extensions along the full list of archive types that 77Zip can work with. The best compression ratios, however, seem to have been reserved for 7z files, together with the possibility of creating self-extracting archive files. The list of archive types you can choose from when creating a new one includes ZIP, TAR, and WIM. Only 7z and ZIP allow for customization when it comes to the compression method used – 7z supports LZMA, LZMA2, PPMd, and BZip2, while ZIP archives can also be compressed using Deflate and Deflate64. Both formats allow for further customization, including the compression level, the size of the dictionary and words, the number of CPU threads to be used, the encryption method, or the possibility of adding a password to the new archive. WIM and TAR files, however, have no access to any of these settings.
The list of well-known supported archives grows when we move to the unpacking area. Here you will find all the usual suspects, such as ARJ, ISO, CAB, CHM, MSI, FAT, NTFS, or RAR. Regrettably, RAR archives, though being one of the most widely used archive formats, do not receive the same level of attention as, for example, ZIP archives, and are supported only at the unpacking side.
77Zip comes with an intuitive and simple interface, being an easy-to-use utility suitable for all types of users, and it also offers a command-line version to those interested. It has been described by its developers both as an open-source and a “free” licensed application. The source files, however, are nowhere to be found, and I could not see any other reference to its open source origin neither in its EULA nor anywhere else in the program’s site.