[Coco] COCO FPGA

Mark Marlette mmarlette at frontiernet.net
Mon Dec 26 10:13:03 EST 2011


Currently have a dev station loaded doing some benchmarking for this approach. 

Currently can mount the FAT file structure is 30mS. 

Passing the FD and having the AVR do the sector translation is trivial in the compiler I am using. 

Different libraries supporting the FAT, so I am writing some benchmarking software to determine which performs best for our application. 

Fun stuff!!!! Trying to get the dev station to develop more FREE time!!! Haven't got that one perfected yet.... :) 

Mark 
http://www.cloud9tech.com 



----- Original Message ----- 
From: "John Kent" <jekent at optusnet.com.au> 
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com> 
Sent: Monday, December 26, 2011 3:41:37 AM 
Subject: Re: [Coco] COCO FPGA 



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. 

-- 
http://www.johnkent.com.au 
http://members.optusnet.com.au/jekent 



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