[TUHS] Origins of the frame buffer device
robpike at gmail.com
Mon Mar 6 18:57:35 AEST 2023
I would think you have read Sutherland's "wheel of reincarnation" paper,
but if you haven't, please do. What fascinates me today is that it seems
for about a decade now the bearings on that wheel have rusted solid, and no
one seems interested in lubricating them to get it going again.
On Mon, Mar 6, 2023 at 7:52 PM Paul Ruizendaal via TUHS <tuhs at tuhs.org>
> Thanks for this.
> My question was unclear: I wasn't thinking of the hardware, but of the
> software abstraction, i.e. the device files living in /dev
> I’ve now read through SunOS man pages and it would seem that the /dev/fb
> file was indeed similar to /dev/fbdev on Linux 15 years later. Not quite
> the same though, as initially it seems to have been tied to the kernel part
> of the SunWindows software. My understanding of the latter is still limited
> though. The later Linux usage is designed around mmap() and I am not sure
> when that arrived in SunOS (the mmap call exists in the manpages of 4.2BSD,
> but was not implemented at that time). Maybe at the time of the Sun-1 and
> Sun-2 it worked differently.
> The frame buffer hardware is exposed differently in Plan9. Here there are
> device files (initially /dev/bit/screen and /dev/bit/bitblt) but these are
> not designed around mmap(), which does not exist on Plan9 by design. It
> later develops into the /dev/draw/... files. However, my understanding of
> graphics in Plan9 is also still limited.
> All in all, finding a conceptually clean but still performant way to
> expose the frame buffer (and acceleration) hardware seems to have been a
> hard problem. Arguably it still is.
> > On 5 Mar 2023, at 19:25, Kenneth Goodwin <kennethgoodwin56 at gmail.com>
> > The first frame buffers from Evans and Sutherland were at University of
> Utah, DOD SITES and NYIT CGL as I recall.
> > Circa 1974 to 1978.
> > They were 19 inch RETMA racks.
> > Took three to get decent RGB.
> > 8 bits per pixel per FB.
> > On Sun, Mar 5, 2023, 10:02 AM Paul Ruizendaal via TUHS <tuhs at tuhs.org>
> > I am confused on the history of the frame buffer device.
> > On Linux, it seems that /dev/fbdev originated in 1999 from work done by
> Martin Schaller and Geert Uytterhoeven (and some input from Fabrice
> > However, it would seem at first glance that early SunOS also had a frame
> buffer device (/dev/cgoneX. /dev/bwoneX, etc.) which was similar in nature
> (a character device that could be mmap’ed to give access to the hardware
> frame buffer, and ioctl’s to probe and configure the hardware). Is that
> correct, or were these entirely different in nature?
> > Paul
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