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From: kjws@eagle.ukc.ac.uk (K.J.W.Smithers)
Newsgroups: comp.sys.amiga
Subject: Re: Still More 68020 Questions
Message-ID: <4131@eagle.ukc.ac.uk>
Date: 9 Jan 88 18:11:58 GMT
References: <8801081459.AA16543@decwrl.dec.com>
Reply-To: kjws@ukc.ac.uk (K.J.W.Smithers)
Organization: Computing Lab, University of Kent at Canterbury, UK.
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In article <8801081459.AA16543@decwrl.dec.com> plouff@nac.dec.com (08-Jan-1988 0946) writes:
>[]
>
>1.  When the operating system recognizes a 68020, what exactly does it 
>do?  Is the '020 instruction cache turned on by ROM Kernel routines (or 
>elsewhere in the OS), or must the user run a separate program?
>
>
>Wes Plouff
	The system recognises the 68020 and turns on the cache. CSA provide
routines to turn the cache on and off. It makes about 30% difference in the
speed of the 68020 for programs like fastman (mandelbrot). I haven't found
a single incompatible program which worked when  i turned off the cache but
i haven't tried very hard. 
	I still can't get my 68020 to work with my A2090 board this may be
a consideration if you are looking at such a system. Also CSA provides a
modification required for b2000 rev 4.0 4.2, 4.1 doesn't work at all! (correct?)
this has to be done to the main board and requires one wire link and one cut 
track.
	Hope this is of use. 
		Kit Smithers
    kjws@ukc.UUCP
or  !mcvax!ukc!kjws