Linux framebuffer

The Linux framebuffer (fbdev) is a graphic hardware-independent abstraction layer to show graphics on a computer monitor, typically on the system console.[1] It allows direct access to the framebuffer (the part of a computer's video memory containing a current video frame) using only the Linux kernel's own basic facilities and its device file system interface. It does not rely on user space software like SVGALib.

Knoppix booting on the framebuffer

Applications

There are three applications of the Linux framebuffer:

  • An implementation of text Linux console that doesn't use hardware text mode (useful when that mode is unavailable, or to overcome its restrictions on glyph size, number of code points etc.). One popular aspect of this is the ability to have console show the Tux logo at boot up.
  • A possible graphic output method for a display server, independent of video adapter hardware and its drivers.
  • Graphic programs avoiding the overhead of the X Window System.

Examples of the third application include Linux programs such as MPlayer, links2, Netsurf, w3m, fbff,[2] fbida,[3] and fim[4] and libraries such as GLUT, SDL, GTK, and Qt, which can all use the framebuffer directly.[5] This use case is particularly popular in embedded systems.

The now defunct[6] DirectFB is another project aimed at providing a framework for hardware acceleration of the Linux framebuffer.

There was also a windowing system called FramebufferUI (fbui) implemented in kernel-space that provided a basic 2D windowing experience with very little memory use.[7]

History

Linux has generic framebuffer support since 2.1.109 kernel.[8]

It was originally implemented to allow the kernel to emulate a text console on systems such as the Apple Macintosh that do not have a text-mode display, and was later expanded to Linux's originally supported IBM PC compatible platform.

gollark: Sure, then.
gollark: Wait, what would we actually find out?
gollark: Launch *us* or a probe? I vote yes for the probe.
gollark: We could start on the ~~giant lasers of death~~ solar power system of peace, though it seems that most of our stuff is self-powered anyway.
gollark: On the one hand, you can get more miners. On the other, they have to ship everything back, and coordination/control is a problem.

See also

References

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