〈 說明

7z archive format

7z format was developed and introduced by Igor Pavlov in 1999.

Used in 7z format, LZMA and LZMA2 are powerful compression algorithms and published as open-source (public domain), so they are used widely in the IT industry.

Advantages of 7z

7z is a relatively new archive format compared to the other old ones. So this format has these advanced features.

  • 7z uses LZMA/LZMA2 compression algorithms of high compression ratio. Especially, LZMA2 is an improved algorithm of LZMA with multi-threading. The more CPU cores, the faster the compression speed is.
  • Supports advanced encryption method (AES256).
  • Supports filename encryption. Without a password, you can’t even access the name of the file in the archive.
  • Supports solid compression, which improves compression ratio when processing multiple similar files.
  • Unicode filenames, Processing large file over 4GBytes, etc.

Disadvantages of 7z

To achieve even higher compression ratio, 7z uses various ways including header compression.

Because of those features, however, it is almost impossible to recover a compressed file when it is damaged even slightly.

Therefore, please be careful not to damage your important files when you backup them in 7z format.

You may find information on how to recover damaged 7z files in 7z website, but making a complete recovery is extremely difficult even for experts.

Learn more: https://www.7-zip.org/recover.html

Features of 7z created by Bandizip

Bandizip creates 7z archive files with its own compression module based on LZMA SDK.

Therefore, when you compress files with Bandizip, the features of the archive files differ from those of the files made on 7-zip as follows:

  • Bandizip creates 7z files with only a single solid block.
  • Bandizip’s file encryption encrypts an archive header.
  • Bandizip supports LZMA2 only, not the other compression algorithms used in 7z format.