Not all archive files are the same and differ according to the storage and compression systems used. But what is an archive file?
Everybody who uses a computer will have had to handle an archive file at least once in their life. Probably without even knowing that it's called that. You know when you download a file in RAR or ZIP format to your PC? Well, they are archive files.
Archive files are very convenient for a number of reasons. They allow you to transfer more files even when - to give you an example - the Internet connection is not optimal or if your mailbox does not allow you to send files of too large a size. And that's not all. Archive files are useful as they take up less space on your devices. What's more, these formats are also suitable for managing and organizing many files in the best possible way. That said, let's try to give a clearer explanation, trying to understand what are the elements that characterize an archive file and what actually these files are used for.
What is an archive file
An archive file is a file composed of other documents - it may happen that it contains only one element - and metadata, that is, "extra" information. Generally, almost all archive file formats use one of many lossless compression methods. They are characterized by the fact that they allow several files to be combined into a single file. This makes it easier to both transfer the content and store it on your devices.
Different Formats
To generate and open an archive file, simply use software, some of which include a free version. Not all archive files are the same and differ according to the storage and compression systems used.
ZIP
One of the most common and widely used archive file formats is ZIP. It was first introduced in 1989 by American computer scientist Phil Katz. It is a free format and is supported by both Windows and Apple operating system computers. The ZIP archive file uses different compression systems. Its main feature is that it doesn't compress files together, but separately. Thus, it is possible to extract all files individually. It is lossless, that is, it lets you store and compress files without altering their original structure. Therefore, it lends itself to being used to send programs or files that cannot be modified.
RAR
Another type of archive file is RAR. Compared to the previous system, the format is not free but proprietary. In fact, it is named after its creator, Eugene Roshal. It differs from the ZIP format since it offers better compression, although the process is much slower. And that's not all. It lets you manage many archives, even complex ones. The RAR format also supports the AES encryption system which means that you can not only archive and compress but also encrypt files. Being a proprietary format, only authorized software can use the RAR compression system. For decompression (i.e. opening files) the format is supported by many programs.
7z
7z is undoubtedly one of the most complete archive formats. First of all, it supports many compression methods. Then, it is also very efficient. In fact, the 7z standard guarantees a high level of compression. It can also handle large and complex file volumes. And that's not all. In fact, the format guarantees a high degree of protection thanks to the Rijndael/AES-256 encryption system. It is an open format and is governed by the free GNU Lesser General Public License.
JAR
Unlike the formats mentioned above, JAR is characterized by being an archive file used to compress Java classes. There are several advantages offered by this system. First of all, the compression standard used makes it possible to considerably reduce the number of files. The JAR format also lets you include other information, such as those referring to the package's creator. Besides, it is very useful since it doesn't alter the compressed files with respect to the original ones. This means that JAR files can be opened by all JVM (Java Virtual Machine) platforms.
Tar
Tape File Archive is a format that allows you to store a huge amount of files in a single archive. The Tape File Archive doesn't have its own compression system, so it has to rely on external programs. Its peculiarity is that it preserves file systems, that is, inside each Tar archive there is a metadata file that contains information about the user, permissions, date and time and more.