EXes

An EXE file is a type of executable binary used by Windows and, in its earliest form, MS-DOS. The .exe extension usually identifies a program intended to be run directly by the operating system.

Modern Windows executables are structured as Portable Executables (PE), a format derived from the COFF specification. A PE file begins with a legacy MZ header, followed by a PE header that describes how to map the file into memory. The file is organized into sections such as .text (code), .data (data), and resources; it may also contain an import table that lists functions supplied by DLLs and an export table for use by other binaries. Digital signatures or certificates may be embedded to verify authorship. The format supports both 32- and 64-bit images.

Execution and loading: When a user or system launches an EXE, the Windows loader maps the file into the process address space, resolves imports from DLLs, and applies relocations so code can run at the expected addresses. Control is transferred to the image’s entry point, which for C/C++ programs typically initializes the C runtime before calling main; GUI applications may begin at WinMain. The file can be statically linked (all code in the EXE) or dynamically linked (reliant on DLLs).

Security and compatibility: Executables can be signed to prove origin; Windows features such as SmartScreen and Windows Defender help detect untrusted software. Because EXEs can host malware, users should obtain software from trusted sources and verify integrity. Cross-platform concerns: EXEs run natively on Windows; other systems require compatibility layers (e.g., Wine) or virtualization. Legacy formats existed for 16-bit Windows (NE/LE) but are largely obsolete.