CHN File

What are CHN files and how to open them

Are you having problems opening a CHN file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CHN files.

What is a CHN file?

CHN files have multiple uses, and ApBasic Chain File/module is one of them. Read more about the other uses further down the page.

ApBasic Chain File/module

We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

How to open CHN files

Important: Different programs may use files with the CHN file extension for different purposes, so unless you are sure which format your CHN file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different CHN openers which you will find listed below.

Last updated: August 31, 2026

All known file formats using extension .CHN

While ApBasic Chain File/module is a popular type of CHN-file, we know of 2 different uses of the .CHN file extension. Different software may use files with the same extension for different types of data.

Turbo Pascal Chain Module

Turbo Pascal Chain Module files store compiled Pascal programs that omit the Pascal runtime library so they can be loaded and executed from another Turbo Pascal program via the Chain procedure. They are produced by the Turbo Pascal compiler in its Chain-file mode for CP/M-80, CP/M-86, or MS-DOS environments. These chain module files are not standalone executables - they assume a host program which has already loaded the common runtime library.

A chain module file is created when the compiler is switched into Chain-file generation mode (often via an Options menu "H" selection). The resulting module contains only the user's compiled code; library routines must be present in the calling program's memory. Execution of a chain module happens when that calling program invokes Chain(fileVariable), which loads the module into memory starting at a specified start address and continues execution there. Compiler settings such as minimum code segment size, minimum data segment size and free dynamic memory must accommodate the largest module involved.

Turbo Pascal Chain Module files begin with a header that indicates they were compiled in chain-mode. They do not include the Pascal library code. The file includes data about code and data segment sizes, but requires that start and end memory addresses be defined so modules do not overlap the library or loader code.

Various apps that use files with this extension

These apps are known to open certain types of CHN files. Remember, different programs may use CHN files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about CHN file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.