Convert A09 to 7Z

Understanding a09 and 7z file formats

A09 files are part of a multi-volume archive set created by the ARJ compression utility, a popular archiver in the 1990s. Each file in the set is named sequentially (e.g., .a00, .a01, ..., .a09) and contains a portion of the compressed data. To extract the original files, all parts of the archive are required.

7Z is a modern compressed archive format developed by 7-Zip. It offers high compression ratios and supports strong AES-256 encryption, making it a popular choice for efficient and secure file storage and sharing.

How to convert a09 to 7z

Direct conversion from .a09 to .7z is not possible, as .a09 is only a part of a split archive. The process involves two main steps:

1. Extract the complete ARJ archive (all parts, including .a09) to recover the original files.
2. Compress the extracted files into a new 7Z archive.

Recommended software for conversion

The best software for this process is 7-Zip, which can both extract ARJ multi-volume archives and create 7Z files. Alternatively, WinRAR or the original ARJ utility can be used for extraction, but 7-Zip is recommended for its simplicity and free availability.

Step-by-step conversion process using 7-Zip

1. Ensure you have all parts of the ARJ archive (e.g., .arj, .a00, .a01, ..., .a09) in the same folder.
2. Right-click the .arj file and select 7-Zip → Extract Here to extract the contents.
3. Select the extracted files, right-click, and choose 7-Zip → Add to archive....
4. In the dialog, set Archive format to 7z and configure any desired compression options.
5. Click OK to create your new 7Z archive.

Summary

To convert an a09 (ARJ split archive part) to 7z, first extract the full archive using 7-Zip, then recompress the files into a 7Z archive. 7-Zip is the recommended tool for both steps due to its compatibility and ease of use.