Subject: Re: shutdown -r
To: None <nigel@ind.tansu.com.au>
From: Colin Wood <cwood@ichips.intel.com>
List: port-mac68k
Date: 08/26/1997 13:24:28
nigel@ind.tansu.com.au wrote:
> 
> Paul Goyette wrote:
> > 
> > On Mon, 25 Aug 1997, John P. Wittkoski wrote:
> > 
> > > Colin Wood wrote:
> > > 
> > > > Hmmm...yeah, I seem to remember someone else saying this at some point.
> > > > There must be some low memory global that we don't quite have the right
> > > > address for on the IIcx which we are touching.  The only problem with that
> > > > idea is that I thought a reboot pretty much wiped everything in memory,
> > > > but I guess maybe it doesn't.
> > > 
> > > How does MacOS determine a cold vs. warm startup?
> > 
> > Well, there's a longword called WarmStart (located at low-memory global
> > location 0x0CFC) that is looked at by (at least) the Slot Manager.  From
> > my admittedly low level of understanding of this code, WarmStart contains
> > a value of 0x574C5343 (or, 'WLSC' in ASCII) to signal a restart.  I
> > haven't a clue as to what the MacOS does differently between the Warm and
> > Cold starts.
> 
> 	I imagine that the main difference is a RAM test. Warm start
> would be shorter because it may not need to test every byte in your
> (up to) 128MB system RAM, and (up to) 2MB graphics RAM.

For me, if I've run NetBSD prior to the current MacOS boot (warm or cold),
it takes noticeably longer to boot (like 30 seconds to a minute or more).

Later.

-- 
Colin Wood                                 cwood@ichips.intel.com
Component Design Engineer - MD6                 Intel Corporation
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I speak only on my own behalf, not for my employer.