BitComet Support Team's BLOG

The file name extension .com has been used in various computer systems for different purposes. Originally, the term stood for "Command file" and was a text file containing commands to be issued to the operating system. This was the practice on many of the Digital Equipment Corporation mini and mainframe computer systems going back to the 1970s.

With the introduction of microcomputers this use of files ending with the extension .com changed. In MS-DOS and compatible DOSes, and in 8-bit CP/M, a COM file is a simple type of executable file. The name of the file format is derived from the file name extension .com (not to be confused with the .com top-level domain), which was originally the extension used for such files. However there is no actual association between the file format and the file name extension in any but CP/M and very early versions of MS-DOS.