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From: Chris.Gehlker@p12.f56.n114.z1.fidonet.org (Chris Gehlker)
Newsgroups: comp.sys.mac.programmer
Subject: Re: ROM in RAM
Message-ID: <29486.27342F47@stjhmc.fidonet.org>
Date: 4 Nov 90 14:53:36 GMT
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> In article <1990Oct31.084937.28930@world.std.com> boris@world.std.com (Boris
 
> Levitin) writes:
> >kr1@bushido (kahlil rowter) writes:
> >
> >>I have been using MacMeter for a while now. I've noticed that my SE/30 
> >>typically spends 50-70% of the time on ROM accesses (no surprise here
> >>right?). So I thought of the ability of 386 (DOS) machines to load its
> >>ROM in RAM thereby cutting down access time and improving overall thruput.
 
> >>Now comes the hard question: Has there been attempts to load the Mac ROM
> >>onto RAM? If not, why?
> >
> >The posession of accesible Mac ROMs or a software copy of them (i.e. 
loadable
> >into RAM) is all that stands between someone with a non-Mac
> 68000-series-based >machine and Mac emulation.

Wait a minute! I've been told by the EEs at work that the Mac has custom
masked ROMS with about 80ns access speed while it's not uncommon for
the typical clone to have 200ns or slower ROM BIOS.  The reason that
no one does ROM shadowing on the Mac is that it's pointless.  This discussion
seems to be treating it as if it were a legal issue.

 

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