Subject: Re: cpu: delay factor
To: Andrew Diller <netbsd@dillernet.com>
From: Michael R Zucca <mrz5149@cs.rit.edu>
List: port-mac68k
Date: 11/07/1997 12:11:37
> >I got pretty far through the boot, but the machine hung at:
> >  sbc0 at obio0: options=1<PDMA>
> >everything before that looked pretty much normal, but i noticed a new line
> >right after identifying my computer (IIvx (68030)):
> >  cpu: delay factor 99
> >
> >any idea what either of these mean and how to fix the former?
> >

The SBC driver has never worked when I try it on my IIvx. I think we're not
doing something correctly on the IIvx when it comes to SCSI. 
But any who... about this cpu delay factor:

> this must be equivalent to the bogomips on Linux--- its some sort of
> measurment of CPU speed.

If I remember correctly I believe the CPU speed factor is just the
time_dbra variable passed in from MacOS. Bascially, at boot one of the
things the ROMs do is a tight dbra loop for a while and then store
the time it took to do that in a low-mem global. This value is
used presumably for some purpose (prob. something to do with the
floppy disk or something). However, it is a poor indicator of
speed, as I remember, since the code is executed out of ROM and if
you run the same code out of RAM you get a different value.

I think there's a blurb about it in IM:Operating Systems Utilities.