[Coco] Floppy disks

[Bruce W. Calkins]

> Unfortunately the basic I have only allows the 35 track single side
> formatting.  Though it is my understanding that NitrOS-9 Level 1

> can be configured to use the entire 80 tracks and both sides.



RS Basic can be patched to use both sides of a double sided disk.  On a CoCo 
1 or 2 this requires 64k on a temporary basis or a new ROM to be permanent. 
For the CoCo 3, in which the ROM is transferred to RAM on start up, a couple 
of POKEs could set the drive look-up table for accessing the back side of 
double sided drives.  In both cases, the maximum number of drive "sides" 
visible to the CoCo was 4.  OS-9 was limited to 3 physical drives by 
hardware issues.  There is also a way to hard code the double sided drives 
to act as two drives for RS Basic.



ALL Forms of OS-9 can be patched for the FULL use of double sided drives. 
Level One Release One was a little difficult, but doable.  There were such 
"minor" issues as having to boot from a single sided disk to get to the 
double sided environment.  Any version of OS-9 after that was just a matter 
of setting the number of sides in the device descriptor.



However; the hardware solution for RS Basic made it impossible to use the 
drives as double sided under OS-9.  Also OS-9 (Not that it mattered much.) 
could not read the "other" side of the alternate side of RS Basic disks.



Bruce W.