At 18:55 Uhr +0100 15.11.2006, Kazuyuki Inanaga wrote:
>1) 040 Mac has a good clock except PowerBook550c.
>2) 030 Mac has a slow clock. (why?)

The '030 Macs have an interrupt hierarchy where the timer interrupts have a
low priority, which means that ticks get lost as soon as there is any
significant I/O load. The Quadra 700 and later '040 Macs can be switched to
a different hierarchy which gives the timer interrupts higher priority.
Apple apparently learned from its A/UX experiences.

Powerbooks are probably closer to the '030 architecture - are there any
Powerbooks with a 53c94 SCSI controller? I don't think so.

	hauke

--
"It's never straight up and down"     (DEVO)