[Coco] Connect CoCo Floppy drive to Windows PC

[Bill Barnes]

IIRC, the PC Floppy controller is "sleeping" because when they designed it, they designed the supporting structure to reset the FDC chip every time the sector 0 sync hole came along. The CoCo didn't do that. Because of this there is an unused gap between the sync and chip "reset" recovery before it can write or read to the disk. It's in that gap, where the CoCo writes because it isn't clobbered over the head every sync to reset, that the PCs have a difficult time reading or writing to a CoCo disk that was formatted on a CoCo. Formatting a CoCo disk on the PC eliminates the unreadable time frame, as far as the PC is concerned, and the CoCo could care less that that gap exists.

-Later!   -WB-    -- BABIC Computer Consulting.


--- On Sun, 1/18/09, Torsten Dittel <Torsten at Dittel.info> wrote:

> From: Torsten Dittel <Torsten at Dittel.info>
> Subject: Re: [Coco] Connect CoCo Floppy drive to Windows PC
> To: coco at maltedmedia.com
> Date: Sunday, January 18, 2009, 9:06 AM
> Robert Gault schrieb:
> > Both omniflop.sys and fdrawcmd.sys can have problems
> reading disks formatted on a Coco. It is not the sector data
> or overall structure that is the problem but the low level
> format.
> 
> Actually the PC floppy controller is "sleeping"
> for a period of time after the index hole passes by. The
> track header of a CoCo formatted disk is quite short, so the
> floppy controller sometimes misses the sector header of
> sector 0. I could improve my results of reading CoCo
> formatted disks with a CoCo drive connected to the PC by
> playing around with the drive's speed while repeatedly
> reading sector 0 (in theory just slowing it down, although I
> darkly remember, I couldn't really proove that).
> 
> Regards,
> Torsten
> 
> 
> 
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco