On Fri, 22 Aug 2008 03:23:07 +0100, NVangogh wrote:

> if i try to start it as ordinary user there are lots of error messages
> (posted in earlier thread already) but seems to work fine as root.

Because it needs to open, map and write to the graphics device, and for
whatever reason it's always been thought that that would be a bad thing
for unprivileged processes to be able to do. Large chunks of the X
server tends to blur the destinction between what you would expect to
find in a device driver and what should be in user space. You certainly
don't want something as large and gnarly as X to be part of the kernel,
but you do want it to be able to do some things that usually only kernel
things can. So it's a special case.

Often enough people come up with designs for abstractions and what-not
that would allow for a more traditional server/device split, and that
would probably allow the server to run untrusted, but historically those
sorts of things have made the server run slower, and hardly anyone likes
that.

--
Andrew