Christopher R. Bowman wrote:
> 
> On Wed, 8 Oct 1997, Colin Wood wrote:
> 
> > David G Taylor wrote:
> > > 
> > > Will an external cache card work in a Mac IIci ?
> > > 
> > > I have it enabled in MacOS, but I notice the generic 1.2.1 kernal has
> > > external cache disabled:
> > > options         DISABLE_EXT_CACHE # Don't use IIci external cache
> > > 
> > > ? Any experience here appreciated.
> > 
> > At the moment, no, it won't.  The problem is that I don't think there is
> > any code in locore.s to flush the cache when necessary (the only time it's
> > necessary actually, is during boot).  I think that the machine will hang
> > if you try to boot with the cache enabled.  However, I could be wrong,
> > it's been a while since I've played with turning one on.
> > 
> 
> Sorry, but I thnk your wrong, are you sure enough that I should open
> my machine to double check? 

Just in case I've confused people, I don't think that a IIci with an
external cache will boot on a kernel with the

options 	DISABLE_EXT_CACHE

line removed or commented out.  If you have compiled a custom kernel with
this line removed and/or commented out and it works for you, please let me
know.  I haven't tried to boot my machine with only a cache card in quite
a while, so I'm not 100% positive on this one.  Currently I use a Daystar
accelerator (not that it makes much of a difference w/o the cache :-), and
if I enable the cache on it, it will hang during boot around the copyright
message.  Although I have some code from Kevin Radke which I've hacked on
a little bit to enable the cache, it seemed to make my system somewhat
unstable on the whole.  I would think that the standard IIci cache would
have similar problems since both are a physically addresses
cache...however, I could easily be wrong.

Does this explain things?  Anyone with more of a clue than I, please clue
me in!

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.