Reference

ARJ

ARJ is a DOS-era compressed archive format that bundles and shrinks files, like ZIP. It was known for strong compression and multi-volume archives that could span several floppy disks, but is now largely obsolete.

Files & formatsGeneral

ARJ

Also known as: ARJ file, .arj archive, Archived by Robert Jung

DOS-era compressed archive format
Supported multi-volume archives across floppies
Largely obsolete; opened by 7-Zip

A DOS-era archiver

ARJ (named after its author, Robert Jung) was a popular file-compression archive on MS-DOS, competing with ZIP and LHA. It offered good compression and the ability to split a large archive across multiple floppy disks.

Today it is rarely created, but .arj files survive in old software collections and backups.

Opening ARJ files

Tools like 7-Zip and The Unarchiver can extract ARJ archives. Multi-volume sets need all the parts present to unpack correctly. Re-compress to ZIP or 7z for modern use.

Related terms

Keep reading the reference.

Files & formatsZIP archiveA ZIP archive bundles one or more files into a single compressed .zip file that is smaller and easier to share. Unzipping it creates a second, full-size copy of the contents — so an archive and its extracted files can both take up space at once.General Files & formats7Z (7-Zip)7z is an open archive format from the free 7-Zip tool, known for a very high compression ratio thanks to LZMA/LZMA2. It typically packs tighter than ZIP, but the recipient needs a 7z-capable app to open it.General Files & formatsArchive fileAn archive file bundles many files and folders into one container — for example a ZIP, RAR, or 7z. Most archives also compress their contents to save space, but some (like plain TAR) only bundle without shrinking anything.General