[Coco] 256k upgrade

David Hazelton davehazelton at comcast.net
Tue Feb 2 23:41:54 EST 2010


maybe this would help us remember, I have a J&R 512k on a CoCo 1 that 
has never seen Nitros9.


  [Coco] 256K J&R Banker and OS-9

*A Schober* afs762002 at yahoo.com 
<mailto:coco%40maltedmedia.com?Subject=Re:%20%5BCoco%5D%20256K%20J%26R%20Banker%20and%20OS-9&In-Reply-To=%3C20051228213829.25401.qmail%40web34212.mail.mud.yahoo.com%3E>
/Wed Dec 28 16:38:29 EST 2005/

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------------------------------------------------------------------------
After some rifling through boxes, I've found a
discussion of this product in Hot Coco, Sept 1985, pp.
28--31 (Schematic + test program). Maybe some
relevant info:

QUOTE

...you have either 4 banks of 64K or eight banks of
32K. You switch memory addresses using PEEK commands
to the following addresses:

ffc0-ffc7 64k bank select
ffc8-ffcf 32k bank select
ffd0-ffd7 vdg select
ffd8-ffdf reserved for future 512K upgrade

. . .

J&R's upgrade design is, as far as we know, compatible
with the stock 64K CoCo with one exception. A problem
arises if you program the SAM using the CLR command,
because a CLR command PEEKs and the POKEs 00s to
memory. You can fix this by replacing all offending
CLR commands with STA commands (e.g. STA $ffc0).

. . .

PEEKs needed to change the graphics memory page
accessed by the VDG:

peek vdg bank
ffd0 0
ffd1 1
etc...
ffd7 7
ffd8-ffdf reserved for future expansion

0000-7fff 8000-feff
peek lower bank upper bank
ffc0 0 0
ffc1 1 1
ffc2 2 2
etc...
ffc7 7 7
ffc8 0 1
ffc9 0 2
ffca 0 3
etc...
ffcf 0 7

END

Maybe this is helpful?

-Arnold Shober

--- Robert Gault <robert.gault at worldnet.att.net 
<http://five.pairlist.net/mailman/listinfo/coco>>
wrote:


 >/ At the very least, make the documentation available. /
 >/ New drivers could /
 >/ be written if needed. /
 >/ /
 >/ Bruce W. Calkins wrote: /
 >/ > Regrettably, Most of my CoCo's have been in /
 >/ storage since my move summer /
 >/ > '04. So I've done little with them. /
 >/ > /
 >/ > The J & R Banker requires a change in the boot /
 >/ sector of the OS-9 Level /
 >/ > One disk. The program is in RS-Basic, so someone /
 >/ with a understanding /
 >/ > of what's where on the OS-9 disk should be able to /
 >/ figure out what is /
 >/ > changed to accommodate the increased RAM. /
 >/ > /
 >/ > In Summary, the J & R Banker operates in 64k for /
 >/ OS-9 Level One, with /
 >/ > the availability of a RAM-Disk, and I expect it /
 >/ will do the same for /
 >/ > NITROS9 L1 for CoCo 1 machines. The lack of CoCo /
 >/ 3 specific hardware /
 >/ > will limit its use of the 9309 optimized code as /
 >/ used in the CoCo 3. /
 >/ > /
 >/ > Do you need the documentation and/or the software /
 >/ that goes with the /
 >/ > hardware? /
 >/ > /
 >/ > Bruce W. /
 >/ > /
 >/ > /
 >/ > Boisy Pitre wrote: /
 >/ > /
 >/ >> Bruce Calkins and I had some discussion about /
 >/ this, though I don't /
 >/ >> think I ever got any driver software from him. /
 >/ If you come across /
 >/ >> it, let me know and I'll put it in the NitrOS-9 /
 >/ Project repository. /
 >/ >> /
 >/ >> Boisy /
 >/ >> /
 >/ >> On Dec 28, 2005, at 7:59 AM, A Schober wrote: /
 >/ >> /
 >/ >>> I have come across a 256K J&R Banker in a CoCo I /
 >/ (with /
 >/ >>> 6309!). Is it possible to run OS9/L2 (or /
 >/ NitrOS9) /
 >/ >>> with such a memory switcher? /
 >/ >>> /
 >/ >>> Thoughts? /
 >/ >>> /
 >/ >>> -Arnold Shober /

On 2/2/2010 08:44 PM, Bruce W. Calkins wrote:
> ----- Original Message -----
> From: "Robert Gault"
>
>>> One Caveat; they provided support for OS-9 Level 1, but no one has yet
>>> figured out what needs correcting for NitrOS9 Level One. Quite simply,
>>> NitrOS9 will not boot.
>>>
>>
>> Bruce,
>> This is new to me. Are you saying that with this specific 256 
>> upgrade, NitrOS-9 Level I won't boot or that there is a more general 
>> problem with NitrOS-9 LI?
>>
>
>
>
> OS-9 needed a modification to run on the 256k equipped CoCo.  The disk 
> had a Basic script that modified a sector or two on an unmodified copy 
> of the boot disk after verifying that it was a unmodified boot disk.  
> You could then use the modified disk to create any further boot 
> disks.  So far, nobody has identified just what modifications were 
> made to what modules.  NitrOS9 will probably need similar 
> modifications made to run on the 256k banker modified CoCo.
>
>
>
> Bruce W.
>
>
> -- 
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco
>




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