[Coco] The perfect mas storage for the coco

[Gene Heskett]

On Wednesday 26 June 2013 12:33:48 T. Franklin did opine:

> A little further investigation... These are all over E-Bay. They run
> from $30 to $80 US. Do a search for Floppy Emulator. Most come out of
> China. They all look different but have a common theme and from what I
> can tell, the same PCB inside. The one I bouth looks to have the same
> (or close to) PCB as the IPCas one which Steve state sells for $300+. I
> found one selling in the US and bought it just for kicks. I does
> require special format software (free download).
> 
> Perhaps someone can tell me how to configure the CoCo to run a 1.4K
> floppy with 512 byte/sec floppy? If it can be done.
> 
It hasn't been done primarily because rbf.mn is so well married to the 
concept of a sector being 1 byte (256 bytes) sized.  There are some 
workaround hidden in some of the drivers for hard drives by buffering the 
whole 512 bytes, then handing os9 the first, or last half of that buffer 
for data depending on the odd/even status of the address being used.

It has not to my knowledge ever been moved to the floppy drivers as it adds 
quite a bit of essentially duplicated code, and in any event the WD17X3 FDC 
chip cannot run at the higher baud rates required, its stuck at 256 
kilobaud maximum.

That leaves the same choice that the Amiga's faced with an FDC chip unable 
to run at the higher baud rates, slow the drive down in order to pack more 
bits per inch of track in.  In the 3.5" drives, the fact that the drive and 
disk are mechanically synchronized by the pin drive in the disc hub is the 
only thing that made it even worth trying because the only drive ever made 
to run that slow by Chinon could be seen to be visibly 'cogging' as it 
turned, which if applied to the non locked 5.25" format would have had the 
data rate wobbling by an octave or more in the worst case non synched 
condition.  I don't care how much thrust you use, that pig isn't going to 
fly in terms of error rates.

If WD had ever applied the shrinks to get the WD1773 up to a magabaud data 
rate, we would not be having this discussion.  The end result today of 
course is either 1 or more hard drives, or drivewire 4, or both.  Paranoid, 
I have 2 HD's and drivewire.
 
> In any event, I actually bought it for work as some of our legacy
> machines still use floppies and I'm on my last working floppy drive.
> 
> 
> -----Original Message-----
> From: billg999 at cs.uofs.edu [mailto:billg999 at cs.uofs.edu]
> Sent: Wednesday, June 26, 2013 07:22 AM
> To: 'CoCoList for Color Computer Enthusiasts'
> Subject: Re: [Coco] The perfect mas storage for the coco
> 
> > On 6/25/2013 5:19 PM, Rick Taylor wrote:>> There seem to be a lot to
> > choose from out there. Such as (I have no>> affiliation):
> > http://www.ipcas.com/blog/tag/usb-floppy-emulator/>>>> Has anyone
> > used one of these or similar? What's your experience like?>> Any>>
> > pitfalls?>>> I see one big pitfall: The $325.37 price tag. (EUR 249)I
> > hadn't seen that, but it does confirm my suspicions. :-)bill--Coco
> > mailing
> > listCoco at maltedmedia.comhttp://five.pairlist.net/mailman/listinfo/coc
> > o
> 
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> Coco at maltedmedia.com
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Cheers, Gene
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