[Coco] Four floppy drives?

[Mark J. Blair]

> On Aug 5, 2015, at 11:46 , David Gettle <david17361 at gmail.com> wrote:
> 
> You misunderstood me, under DECB the 4 drives were accessed as SSDD, the
> second side of the drives were not accessed. under OS-9 all 4 drives were
> accessed as DSDD due to the OS-9 software access method, the entire drive
> under OS-9 is accessible from 1 address line.


I'm not seeing how that is possible using a standard Radio Shack controller and normal Shugart-interface floppy drives. There aren't enough signals available on the interface to address four double-sided drives, as implemented by Tandy. The Shugart interface requires 5 signals to do that (1 side select + 4 drive selects), and the Tandy CoCo controllers only provide 4 signals.


-- 
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/