In article <4449D2AF.2070308@tadpole.com>
garrett_damore@tadpole.com wrote:

> Out of curiosity, why not use CPU INT5 (CP0 clock interrupt) for
> hardclock? 

Not sure, but I guess:
- native OSes (Ultrix, WindowsNT etc.) don't use it
- MIPS1 CPUs don't have it (but have common external timers?)
- external timers could be more flexible then internal one
- no certain way to get precise CPU clock frequency on all models
  (but external timer clock is CPU indepenedent?)
etc?

> I never even knew there was support for a separate statistics clock.

It is mentioned in the D&I of 4.4BSD section 3.4,
but I don't know it's still useful for modern systems.
(the example in the book is hp300)
---
Izumi Tsutsui