COM, DOS Command File (.com)
The COM Executables file format
The COM file extension is used for programs that can be executed by running MS-DOS on a Microsoft Windows machine. It can be compared to EXE files even though COM files are significantly smaller and thus contain less data than the EXE file. While EXE files are used to execute whole programs, COM files usually execute a set of instructions only.
Technical details of COM files
COM files share many similarities with EXE files. They are saved in a binary format, however what distinguishes it from EXE files is that the header contains no metadata and the maximum file size of a COM file is 64 KB. The structure of the COM file allows it to be loaded in memory and also be executed from there. The COM file extension should not be confused with the internet domain of the same name. Furthermore, COM files are easily infected by malware and should thus be thoroughly checked before opened/run.