[Coco] micro drive configuration

[Frank Pittel]

Roger,

While I think I understand what it is that you're trying to do I
don't completely understand the need. These days CF and SD cards are
stupidly cheap and for a coco so large as to be a waste of space. Could
you really fill up a 1gig card with nitros software or data?

I'm not sure if it's worth rewriting coco disk basic and the nitros
drivers over.

the other Frank

On Tue, Oct 13, 2009 at 10:28:25PM -0500, Roger Taylor wrote:
> I have an idea here that I need some feedback on in case I'm missing  
> something that might sneak up on me too late.
>
> Take a 2 gig "memory card" of any kind that the CoCo is interfaced to  
> and can access raw sectors for the memory and treat it as a "drive" for 
> OS-9 or Disk BASIC.  Currently, there may be systems in use that use 
> partitions to mark off an OS-9 area and a Disk BASIC area, or possibly 
> other areas.  I'm guessing that they 256-byte sector controllers so that 
> 1/2 of the memory card isn't lost.  If the sectors are 512 bytes, then 
> the OS probably uses both halves of the sector which requires extra 
> overhead... which I'm about to talk about.
>
> What if the memory card and host controller only dealt with 512-byte  
> sectors.  Would it be absolutely silly to let OS-9/NitrOS-9 have the  
> first half of the sector from LSN to LSN(end) and Disk BASIC have the  
> 2nd half of the sector from LSN0 to LSN(end) ?  I realize that a  
> read/write is involved for every write to retain the other OS'es sector, 
> and that a certain amount of speed would be lost for the overhead.  The 
> benefit would be that a 128mb, 256mb, 1gig, or 2gig (just examples) 
> memory card can be dropped in without having to tell the CoCo "OS" 
> anything about partitions or areas to stay out of.  The idea is to use 
> the drive in a parallel fashion and in the simplest fashion, with no 
> BASIC config program having to be used to configure the "drives".  A 2 
> GIG card would yield 1 GIG for OS-9/NitrOS-9 and 1 GIG for Disk BASIC 
> virtual drives, but then only 256 drives are ideal so this is what I'm 
> trying to work around without wasting any "hard drive" space.
>
> Of course OS-9 and DIsk BASIC both would have to use only 256 byte sectors.
>
> -- 
> ~ Roger Taylor
>
>
>
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