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Re: Graphics performance under linux
On Sun, May 13, 2001 at 12:32:25PM -0700, Hashem Masoud wrote:
> Correct me if I'm wrong: unix systems (including
> linux)
> use a client/server based graphics system, the X
> windows system, which has the disadvantage of being
> slow compared to windows or OS/2...
Not true. It depends *a lot* on the card you're using, and the support
from the X server for that card. For example: my old Matrox Mistique
PCI (1280x1024@76Hz 16bpp) in my desktop machine still outperforms the
newer Silicon Motion SM720 AGP chipset in my notebook (1024x768@60Hz
16bpp). Why? Because the XFree86 support for Matrox chipsets is much
better.
And if we're speaking about Unix systems in general: no PC video system
comes even *close* to the performance of an sgi Infinite Reality 3. And
yes, it runs X windows (with OpenGL extensions)
> Q1: what is the other system used in windows and OS/2,
> is it system calls?
In windows programs are allowed to write directly to video memory.
Also, in Windows (and maybe in OS2), the windowing stuff is part of the
OS kernel itself (one of the big flaws in Windows), so for programs it
is just a system call away, while in Unix systems the X server is just
another process and programs use a network connection (Unix sockets or
TCP/IP) to talk to the X server.
> Q2: why isn't the other system (for performance
> reasons) implemented in linux
It is. It's called the XFree86-DGA (Direct Graphics Access) extension.
Erik
--
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands
Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/
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