What is MIME type "text/x-nasm"?

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

The MIME type text/x-nasm labels plain text files that hold assembly source code for the Netwide Assembler (NASM).
Files with this type include those ending in ASM or NASM.

These files are plain text. They contain low-level instructions that can be translated into machine code.
Editing tools often provide syntax highlighting to make the code easier to read.

Primary use: Writing assembly language code for programs that need to be assembled into executables.
Key fact: The files are not directly executable. They require the NASM compiler to produce a working program.
Additional use: Used in educational contexts to study and teach assembly language programming.

Learn more about assembly programming and NASM on the official website: NASM Official Website.

Associated file extensions

.asm, .nasm

Usage Examples

HTTP Header

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


    Content-Type: text/x-nasm

HTML

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


    <a href="file.dat" type="text/x-nasm">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', 'text/x-nasm');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.asm, .nasm

FAQs

What is the text/x-nasm MIME type used for?

The MIME type text/x-nasm specifically identifies source code files written for the Netwide Assembler (NASM). While these are essentially plain text files, this specific label helps development tools and web servers recognize that the content is assembly language, typically associated with the .asm or .nasm extensions.

How do I open or edit a file with the text/x-nasm type?

Since text/x-nasm files are plain text, you can open them with any standard text editor like Notepad, TextEdit, or Vim. However, for a better experience, developers usually use advanced editors like Visual Studio Code, Sublime Text, or Notepad++, which provide syntax highlighting for assembly instructions.

Can I run a text/x-nasm file directly on my computer?

No, files labeled as text/x-nasm are source code and cannot be executed directly. You must first use the NASM assembler to assemble the code into an object file, and then link it to create an executable binary (such as an .exe or ELF file) that the operating system can run.

How do I configure Apache to serve .asm files as text/x-nasm?

To ensure your Apache server serves .asm and .nasm files with the correct MIME type, add the following line to your .htaccess file or main configuration:
AddType text/x-nasm .asm .nasm
This ensures browsers and clients understand the specific nature of the content.

How do I add text/x-nasm support to Nginx?

For Nginx, you need to update the mime.types file or include a types block inside your server configuration. Add the following entry:
types { text/x-nasm asm nasm; }
After saving the configuration, reload Nginx to apply the changes.

Why does my browser download the file instead of displaying it?

Browsers are designed to render HTML, images, and standard text/plain content. Since text/x-nasm is a non-standard type (indicated by the x- prefix), many browsers default to downloading the file. You can force the browser to display it by sending the header Content-Type: text/plain instead, or by installing a browser extension that supports syntax highlighting for code.

Are text/x-nasm files dangerous?

The files themselves are harmless plain text and cannot harm your computer just by being opened. However, because they contain low-level assembly instructions, once they are assembled and executed, the resulting program has direct access to system hardware. You should only compile and run assembly code from trusted sources.

General 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.