[Coco] COCO FPGA

[John Kent]

On 26/12/2011 8:21 PM, Mark McDougall wrote:
> On 26/12/2011 3:32 PM, Frank Pittel wrote:
>
>> I can get 2gig SD cards here for $4 so I don't mind wasting even a 
>> lot of
>> space but a 2gig card for 4 180K floppies is a bit to much waste!!
>
> I don't think anyone here would propose using an entire SD card for 4 
> floppy images. It would be almost as painful as using actual floppy 
> drives.
>
> I would propose that a FAT-formatted SD with floppy disk images, and a 
> mechanism for 'mounting' the images would be the most sensible 
> solution by far. Even using the HDBDOS 255-drive mechanism would be a 
> vast improvement (and as I mentioned, already implemented (read-only) 
> on my Coco).
>
> I'm sure Gary has something similar up his sleeve...
>
> Regards,
>

Yes, you'd need to pass some sort of file descriptor to what ever 
co-processor you are using to implement the FAT file system, to specify 
the disk image. Once you have the disk image mounted for the drive 
number the file system can simply translate the sector  in the FAT file 
system  to the sector or sector pair used by the CoCo.

I do have a FAT file system for the AVR Mega 32 but it required a bit of 
work translating the low level driver code which was written in some 
sort of assembler or low level BASIC. The File system was written in C.

John.

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