[Coco] high density floppy controller mods

[farna at att.net]

Joel, what puzzles me is why no one has ever attempted to use one of hte PC multi I/O chips to build a no halt controller. The chips with floppy, IDE, parallel, and serial ports built in. I recall the cards for ISA slot machines being rather small. I'm not sure you can get 8 bit MIO chips anymore, but surely a buffer arrangement for a 16 bit chip could be worked out. The only problem I can really see is that it may only work with OS9 and not DECB due to the limited room to modify the ROM code. If only the disk controller worked for DECB that would be an accomplishment though. No-halt operation is only good for OS-9 anyway. I'm sure these chips are available, some of the single board controller/computers use them. There are quite a few 16 bit single boards, not sure if any 8 bit are made anymore. 

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 -------------- Original message ----------------------
> 
> Message: 4
> Date: Sat, 05 Aug 2006 13:21:01 -0500
> From: Joel Ewy <jcewy at swbell.net>
> Subject: Re: [Color Computer] [Coco] high density floppy controller
> 	mods
 
> Mike Pepe wrote:
> > James Diffendaffer wrote:
> >> So is there a summary of these mods somewhere?
> >>
> >
> > here:
> >
> > http://www.doki-doki.net/~lamune/computers/coco/hd-floppy/
> >
> > -Mike
> >
> Very cool, Mike. 
> 
> My 3029 has the MB8877_ <-No 'A'.  Anybody have any idea if this is
> significant, speed-wise?
> I'm very tempted now to get out my Disto schematics and bash them
> together with yours to get a high-density controller with a sector
> buffer for no-halt operation, and a 28-pin EPROM socket or two.  If I
> did attempt to build such a thing, I would start over on a new PC board,
> just using the MB8877 chip and the data separator from the original
> controller.  I've got a homebrew CNC PCB drill press that's just waiting
> to punch holes in some copper-clad...
> 
> JCE
>