What is ARJ?

ARJ (Archived by Robert Jung) was one of the most popular compression formats during the DOS and early Windows era (1991-2000). It offered better compression than ZIP at the time and included features like multi-volume archives, password protection, file comments, and damage recovery. ARJ was widely used on bulletin board systems (BBS) for distributing shareware and on floppy disks for software installation spanning multiple diskettes.

ARJ is now obsolete and rarely encountered except when accessing old archives from the 1990s. IT professionals may encounter ARJ files in legacy data archives, old software collections, or retro computing projects. Modern archiving tools like 7-Zip and WinRAR can still extract ARJ files for compatibility. The format was succeeded by RAR, 7Z, and modern ZIP implementations with better compression algorithms.

Did you know? ARJ was the standard compression format on most BBS systems in the 1990s!

History

Robert K. Jung created ARJ to provide efficient compression and advanced features for the DOS platform during the shareware and BBS golden age.

Key Milestones

  • 1991: ARJ 2.0 released for DOS
  • 1993: Widespread BBS adoption
  • 1995: Peak popularity era
  • 1998: Windows ARJ versions
  • 2004: Development ceased
  • Present: Legacy format only

Key Features

Core Capabilities

  • Multi-Volume: Floppy disk spanning
  • Encryption: Password protection
  • Recovery: Damage protection records
  • Comments: File annotations
  • Chapter Support: Archive organization
  • Self-Extracting: EXE archives

Common Use Cases

Legacy Archives

Old data recovery

Retro Gaming

DOS game distributions

BBS Files

Bulletin board archives

Archival

1990s software collections

Advantages

  • Good compression for its era
  • Multi-volume support
  • Damage recovery features
  • Password protection
  • Self-extracting archives
  • Historical significance
  • Still extractable today

Disadvantages

  • Obsolete and discontinued
  • Inferior to modern formats
  • Limited software support
  • Slower than modern algorithms
  • No active development
  • Mostly historical interest only

Technical Information

Format Specifications

Specification Details
File Extension .arj
MIME Type application/x-arj
Compression Proprietary algorithm
Platform DOS, Windows (legacy)
Status Discontinued (2004)
Era 1991-2000 (peak)

Common Tools

  • Extraction: 7-Zip, WinRAR, PeaZip
  • Legacy: ARJ.EXE (DOS original)
  • Modern: Total Commander, IZArc
  • Linux: unarj, arj package