Subject: Re: FreeBSD Bus DMA
To: Ted Lemon <>
From: Perry E. Metzger <>
List: tech-kern
Date: 06/11/1998 23:18:50
Ted Lemon writes:
> Why do you have to have different code?   Why not try the current code
> on for size, see how it works, and *then* propopose i386-specific
> enhancements if the need arises?
> It *sucks* that we're still not going to have sharable device drivers.
> Device drivers are thin on the ground in the Free BSD community.

I think it *sucks* that we have three different unencumbered BSD
development camps, frankly, but I don't see how to fix that.  Also,
once Charles finishes the kernel multithreading project, our code
isn't going to look sufficiently like traditional BSD code any longer
in major sections (synchronization primitives being pretty damn major) 
that it may become impossible to share drivers anyway.

The real tragedy overall is that we have the multiple divergant
development streams in the first place, but it appears that we're way, 
way, way past the point where anything can be done about
that. Luckily, everyone follows POSIX and XPG these days (some perhaps 
closer than others) so at least all our userland code will continue to 
be largely sharable.

> I think it's worth a *lot* of effort to try to improve device driver
> sharing.  I'm not saying this with the intent of offending anybody -
> I think it's a fairly obvious truth.  An incompatible API ought to
> be a *clear* win, and it ought to be *minimally* incompatible.
> Nothing I've heard so far suggests that this is the case.

I believe that the FreeBSD camp believes (based on what evidence I
don't know) that FreeBSD is "three times" as fast as NetBSD, and that
NetBSD is totally unusable somehow. Given this belief system, I don't
see what could be done to convince them to try to stay close to what
we do.