The X font server provides a standard mechanism for an X server to communicate with a font

Font

In typography, a font is traditionally defined as a quantity of sorts composing a complete character set of a single size and style of a particular typeface...

 renderer, frequently one running on a remote machine. It usually runs on TCP

Transmission Control Protocol

The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol , and therefore the entire suite is commonly referred to as TCP/IP...

 port 7100.

Current status

The use of server-side fonts is currently considered deprecated in favour of client-side fonts. Such fonts are rendered by the client, not by the server, with the support of the Xft2

Xft

Xft, the X FreeType interface library, is a free computer program library written by Keith Packard. As of version 2.1, it is licensed under a quasi-BSD license....

 or Cairo

Cairo (graphics)

cairo is a software library used to provide a vector graphics-based, device-independent API for software developers. It is designed to provide primitives for 2-dimensional drawing across a number of different backends...

 libraries and the XRender

XRender

The X Rendering Extension is an X Window System extension to implement Porter-Duff image compositing in the X server, to allow efficient display of transparent images.- History :...

 extension.

For the few cases in which server-side fonts are still needed, the new servers have their own integrated font renderer, so that no external one is needed. Server-side fonts can now be configured in the X server configuration files. For example, will set the server-side fonts for Xorg.

No specification on client-side fonts is given in the core protocol.

Future

As of October 2006, the manpage for xfs on Debian states that:

FUTURE DIRECTIONS

Significant further development of xfs is unlikely. One of the original motivations behind xfs was the single-threaded nature of the X server — a user’s X session could seem to "freeze up" while the X server took a moment to rasterize a font. This problem with the X server (which remains single-threaded in all popular implementations to this day) has been mitigated on two fronts: machines have gotten much faster, and client-side font rendering (particularly via the Xft library) has become the norm in contemporary software.

Performance

User experience show the same performance on both X server with direct font serving and X server with font server path.

Deployment issues

So the choice between local filesystem font access and xfs-based font access is purely a local deployment choice. It does not make much sense in a single computer scenario.

See also

• X Window System core protocol
• X logical font description
  X logical font description
  X logical font description is a font standard used by the X Window System. It is intended to support:* unique, descriptive font names that support simple pattern matching* multiple font vendors, arbitrary character sets, and encodings...