[Coco] Read coco disks on a PC

[Darren A]

On Thu, Mar 15, 2012 at 9:18 PM, John E. Malmberg wrote:
>
> As I stated before:
>
> The buffers are fixed in memory for Disk Basic.
>
> The DISK IO routines will read all 512 bytes first into the disk buffer and
> then overrun into the verify buffer.
>
> But when the ROM routines try to use the data, they will only read the first
> 256 bytes from the disk buffer.
>

Not all operations in disk basic go through the primary buffer at $0600.

Open data files have their own separate buffers and operations like
COPY and BACKUP use free memory to load in multiple sectors.
Overrunning in these cases could corrupt the disk management
structures, the basic program or the stack.

Darren