[Coco] 128K CoCo2

[Kip Koon]

Hi Joe,
I just looked at the article you mentioned below and my 128K upgrade is exactly what the article describes.  I tried the POKE statements and I get no garbage screens so I wonder if I have the wrong Coco 1 on my Computer Data Center table.  I'll have to check that out later though as I am preparing for the CoCoFEST trip.  I have to make sure all the SBCs I want to demo are in good working order!  :)  Let me know your progress on your software project.  An alternate version of NitrOS-9 L1 to take advantage of this 128K modification would be interesting to say the least!  

Kip Koon
computerdoc at sc.rr.com
http://www.cocopedia.com/wiki/index.php/Kip_Koon



> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Joe Grubbs
> Sent: Sunday, April 19, 2015 5:13 PM
> To: CoCoList for Color Computer Enthusiasts
> Subject: Re: [Coco] 128K CoCo2
> 
> Yeah I'd have to write my own code to take advantage of the extra 64K. Just curious if anyone here has actually performed the
> upgrade and if 128K is the practical limit before doing some massive surgery.
> 
> FWIW the article can be found on page 162 of:
> http://www.colorcomputerarchive.com/coco/Documents/Magazines/Rainbow,%20The%20%28Clearscan%29/The%20Rainbow%20V
> ol.%2004%20No.%2005%20-%20December%201984.pdf
> 
> 
> 
> > From: os9dude at gmail.com
> > Date: Sun, 19 Apr 2015 14:41:18 -0400
> > To: coco at maltedmedia.com
> > Subject: Re: [Coco] 128K CoCo2
> >
> > On Sun Apr 19 2015, Joe Grubbs wrote:
> >
> >
> > > While searching for the reverse video mod in old issues of Rainbow,
> > > I stumbled upon an article detailing a simple way to take a CoCo2 to 128K.
> > >
> > > Has anyone ever done this? And is 128K the upper limit *without*
> > > doing massive surgery? This circuit was nice because it retained the
> > > SAM, added a few logic ICs, and used a piggyback set of 4164s
> > >
> >
> > There were several options to go 128k on the CoCo 1/2 and all of them
> > - if I recall correctly - were straightforward 32k bank switching
> > schemes, there was no way for plain old Basic to access the extended
> > RAM for programs but only as a RAM disk or printer spooler.  Maybe OS9
> > could make better use of the extra RAM.
> >
> > Don't recall ever seeing any software marketed for 128k.
> >
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