atr

.atr — Atari 8-bit Disk Image

Atari · 1979

Developer

Atari

Key Features

Sector-by-sector raw disk image.
Preserves original disk structure and boot sectors.
Supports various Atari file systems.
Essential for accurate emulation and archiving.

Best For

Emulating Atari 8-bit floppy disk drives.
Creating exact backups of Atari floppy disks.
Preserving the complete state of a physical Atari disk.
Distributing software that relies on specific disk layouts.

Less Ideal For

Storing individual files for general use.
Sharing data between modern operating systems without an emulator.
Creating compressed archives of multiple files.
Using as a primary backup for modern file systems.

Common Use Cases

Running classic Atari 8-bit games and software on modern computers via emulators.
Archiving original Atari floppy disks to prevent data loss.
Distributing software for Atari emulators.
Studying the file systems and boot process of vintage Atari computers.

How to Open It

Use an Atari 8-bit emulator such as Altirra (Windows, macOS, Linux) or Atari800 (cross-platform).
Mount the .atr file as a virtual floppy disk within the emulator's settings.
Some disk image manipulation tools might offer limited viewing capabilities, but full usage requires an emulator.

What is a .atr file?

The .atr file extension is primarily associated with the Atari 8-bit family of computers, including the Atari 400, 800, XL, and XE series. It represents a raw, sector-by-sector disk image, essentially a complete copy of an entire floppy disk or other storage medium. This format allows for the preservation and emulation of the original disk's structure and content, including boot sectors and file system information. .atr files are crucial for enthusiasts and archivists looking to run classic Atari software or preserve the integrity of original game and application disks.

Programs That Open .atr Files

Platform	Program
Windows	Altirra	Free
	Atari800	Free
macOS	Altirra	Free
	Atari800	Free
Linux	Atari800	Free

How to Convert .atr Files

Format	Method
.ADF	Emulator specific tools, Disk imaging utilities

Common Problems with .atr Files

⚠️ Cannot open .atr file directly in a standard file explorer.

An .atr file is a disk image, not a standard file. You need an Atari emulator (like Altirra) to mount and use it.

⚠️ Disk image may not boot or run correctly.

Ensure the .atr file is a complete and accurate image of a bootable disk, and that your emulator is configured correctly for the target Atari model and hardware.

Frequently Asked Questions

What is the difference between an .atr and a .xex file?▼

An .atr file is a disk image containing an entire floppy disk, while an .xex file is an executable program for Atari 8-bit computers.

Can I use .atr files on modern operating systems without emulation?▼

No, .atr files are designed for Atari 8-bit systems and require an emulator to be accessed and used on modern computers.

Technical Details

An ATR file is a bit-for-bit copy of an Atari floppy disk, meaning it captures every sector exactly as it exists on the physical media. It does not impose a specific file system structure on its own but rather reflects the underlying file system of the source disk (e.g., MyDOS, Atari DOS, SpartaDOS). This raw nature makes it ideal for accurate emulation and archiving.

Did You Know?

The .atr format is a direct sector copy, making it highly accurate for preservation but not efficient for storing just a few files.

Many Atari enthusiasts use .atr images to relive classic gaming experiences on their PCs.

Security Information

.atr files themselves do not typically contain malicious code, but the software or games loaded from them could potentially be harmful if obtained from untrusted sources, as with any executable file.