Subject: Re: Floating point in the kernel
To: Perry E. Metzger <>
From: Charles M. Hannum <>
List: tech-kern
Date: 09/22/1998 11:58:58
> Compressed video decoding under NetBSD so you can watch videos without 
> annoying dropouts?
> Using a NetBSD box as a phone?
> Doing a software modem on your NetBSD box (the originally described
> app)?

*None* of those call for hard real-time in the sense that people have
been spewing about.  Hard real-time is needed for only a very small
subset of applications, and those applications simply are not going to
run on a general purpose OS.  (If you turned off all memory caches and
the MMU, made sure all pointers are aligned, and turned off all
non-essential interrupt sources, then you *might* be able to actually
predict timing with some accuracy.  But I'm skeptical.)

For comparison sake, I point out that BeOS does some pretty snazzy
real-time video just using a carefully tuned lottery scheduler --
which is pretty far from hard real-time.