[Coco] "Reading" non-readable bytes with PEEK vs ZBUG

jdaggett at gate.net jdaggett at gate.net
Fri Jan 25 20:26:51 EST 2008

On 24 Jan 2008 at 22:05, Roger Taylor wrote:

> That's why I did the public test request for MMU PEEK to see what's
> happening.  If I could get 1,000+ confirmations instead of 20 or 30,
> I'd be more happy, but so far the odds of these people being spread
> around the U.S. and globe with not-identical CoCo 3's, I'm a lot more
> than 0% convinced that a 128k/512k CoCo 3 reads back a "01".  I agree
> that this is not a full guarantee, though.


IF it is a random process due ot floating inputs then repeated reads should over time garner 
some typ eof distribution between the four combinations. If it is not random, which I suspect, 
then the same form of corruption should repeat all the time. From the various test done so 
far, the mechanism for corruption tends to lead me to believe that it is not random and that 
the corruption is taking place in the GIME chip. It has to do with with a read of the register 
ad the read of the RAM. 


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