Atari ST TOS archive
File type: Archive and compressed file
A tos file extension identifies an archive associated with TOS (The Operating System or Tramiel Operating System), the operating system used by Atari ST computers.
A tos file can contain archived data or disk-image data intended for use in an Atari ST environment.
Found 2 different file type records with the same tos filename suffix.
File type category:
Archive and compressed file
Date updated: October 16, 2026
TOS, meaning The Operating System or Tramiel Operating System, was the operating system used by Atari ST computers. The Atari ST family included models such as the 520ST and 1040ST, along with F, FM and E variations such as the 1040STE.
The tos file stores an Atari ST archive or disk image.
Use TOS or compatible Atari ST software to work with *.tos files. On a modern computer, an Atari ST emulator can provide the TOS environment in which compatible utilities run.
If the file contains disk-image data rather than an ordinary archive, use it as a disk image through compatible Atari ST software.
If a compatible Atari ST archive utility can extract the contents, the extracted files can then be stored in a modern archive format.
A file containing a disk image should instead be converted or mounted with compatible Atari ST disk-image software. The available options depend on the contents of the particular file.
Software applications that can open tos files:
Other operating systems or devices
File type category:
Settings, options, themes or skins file
Date updated: September 27, 2026
The .tos file extension identifies settings files belonging to The Only Sheet. The file stores settings used by the character creator and maintenance workbook for the Dungeons & Dragons and Pathfinder RPG rule systems.
The Only Sheet is available for Microsoft Windows. A .tos file is used with that software rather than as a general-purpose document.
Open or use a .tos file with The Only Sheet on Microsoft Windows. Load it through the software if it is not opened automatically.
Because the file stores application settings, it may not display useful content in a text editor or another unrelated program.
A .tos file is a settings file rather than an interchange document, so it cannot normally be meaningfully converted to another format.
Keep the file for use with The Only Sheet. If different settings are needed, change them in the software and save a new settings file if the program provides that option.
Software apps that manage or store settings in tos files:
Microsoft Windows
Software applications that handle other tasks involving tos files:
Microsoft Windows
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