What is MIME type "application/x-font-linux-psf"?

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

application/x-font-linux-psf is a MIME type for bitmap fonts used on Linux systems. These fonts display crisp text in low-resolution and text-mode environments.

They serve well in contexts where simple, fixed-width characters are needed. They are common in system consoles, boot loaders, and recovery screens.

Linux terminals: Provide clear text in console mode.
Boot and recovery: Ensure legibility during startup or troubleshooting.
Embedded systems: Offer low-resource font solutions.
Fixed-size rendering: Use non-scalable, bitmap patterns.

This MIME type covers fonts like PSF and its variant PSFU.

For further details on the file format, visit PSF file format details.

Associated file extensions

.psf, .psfu

Usage Examples

HTTP Header

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


    Content-Type: application/x-font-linux-psf

HTML

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


    <a href="file.dat" type="application/x-font-linux-psf">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-font-linux-psf');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.psf, .psfu

FAQs

What is the application/x-font-linux-psf MIME type used for?

This MIME type identifies PC Screen Font (PSF) files, which are bitmap fonts used primarily by the Linux kernel for console text modes. You will typically encounter these files, ending in .psf or .psfu, in system directories like /usr/share/consolefonts rather than in web design.

Can I use PSF fonts in web browsers with CSS?

No, modern web browsers do not support application/x-font-linux-psf natively via the CSS @font-face rule. These are raw bitmap fonts optimized for hardware text modes; if you want a retro terminal look on a website, you must convert the font to a web-compatible format like WOFF or TTF.

How do I configure Nginx to serve PSF files correctly?

If you are hosting a Linux package repository or file mirror, add the MIME type to your mime.types file or specific server block. Use the following configuration: types { application/x-font-linux-psf psf psfu; }.

What is the difference between .psf and .psfu extensions?

While both file types fall under application/x-font-linux-psf, the .psfu extension explicitly indicates a PSF file that contains an embedded Unicode mapping table. This allows the Linux console to correctly map byte sequences to Unicode characters, which is essential for displaying non-ASCII text.

How do I add support for this MIME type in Apache?

To ensure Apache serves Linux console fonts with the correct Content-Type header, add the following directive to your .htaccess file or main configuration: AddType application/x-font-linux-psf .psf .psfu.

Why does the MIME type start with 'x-'?

The x- prefix in application/x-font-linux-psf indicates that it is a non-standard or vendor-specific subtype. It is not part of the official IANA MIME registry standard tree but is widely recognized within the Linux ecosystem for handling console fonts.

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.