[Coco] Interesting thoughts on the HD6309

[jdaggett at gate.net]

The first patent that I found referencing this was back in 1969.  
RCA/Honeywell/IBM were active in developing computers and components for 
the Apollo and Gemini Space programs using core memory and LSI chps.  

This concept predates microprocesor chips by about four or five years. 

james

On 7 Feb 2007 at 12:30, Richard Atkinson wrote:

> I think the MOS Technology 6502 has this feature. Possibly Motorola
> themselves could have implemented it in the 6809, but decided against
> it for patent reasons?
> 
> Richard
> 
> 
> On 2/4/07, jdaggett at gate.net <jdaggett at gate.net> wrote:
> >
> > Interesting find.
> >
> > Again as I was searching the patents on the US Patent Database, I
> > cam across a Motorola Patent that also references other patents by
> > RCA and Honeywell. I think I better understand  the reason the
> > hidden feature of the 6309 when it does an instruction fetch while
> > executing a previous instruction remained unpublished. It seems that
> > Motorola did a patent on this feature but also there were 9 previous
> > patents on this same subject.
> >
> > Microprocessor having instruction fetch and execution overlap
> >
> > It more appears that Hitachi had implemented it in the 6309 and just
> > before release of the product  info, their lawyers determined that
> > any info about this mode would violate not just a Motorola patent
> > but maybe also ones by RCA and Honeywell also. It is easier to fight
> > one company in a patent infringement suit. To fight three or even
> > four companies is far to difficult and costly.
> >
> > It looks as if Hitachi could not find a way around the ten patents
> > and thus never deleted the feature. Instead they were silent about
> > it and hoped no one would find out about it. By the time the
> > community had found out about this feature,some of the original
> > patents had expired and Motorola's was also near expiration. Also no
> > one decided to persue infringement because Hitachi failed to
> > document this feature and not use it as a selling point or an
> > invention of their own.
> >
> > james
> >
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> > Coco at maltedmedia.com
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> >
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