What is MIME type "application/x-ms-dos-executable"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

application/x-ms-dos-executable identifies files built in the DOS MZ format. These files contain low-level binary code that the operating system can run directly. They follow an old header structure that begins with the signature “MZ” which was standard in early DOS systems.

This MIME type is mainly found in legacy applications. It is typical for programs and dynamic libraries, like those marked by the EXE and DLL file formats.

Legacy Compatibility: Used by older software running in DOS or compatibility modes.
Executable Code: Contains compiled machine instructions that interact directly with system hardware.
File Identification: The "MZ" header helps systems and security tools recognize these executables.

This MIME type helps operating systems and security programs treat the file as executable code, which is important for both running applications and scanning for malware. For more details on DOS executables, see this reference.

Associated file extensions

.exe, .dll

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-ms-dos-executable

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-ms-dos-executable">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');
    
    http.createServer((req, res) => {
      res.setHeader('Content-Type', 'application/x-ms-dos-executable');
      res.end('Content here');
    }).listen(3000);

Associated file extensions

.exe, .dll

FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.