[Coco] Disk Basic and 512 byte block floppies.

[Arthur Flexser]

On Fri, 16 Jan 2004, (tim lindner) wrote:


> <snip>

> 

> Interesting experiement.

> 

> The size of each sector is written to the disk. Disk BASIC expects all

> the sectors to be 256 bytes, it doesn't check. It create 256 byte blocks

> of RAM to read to and from these sectors.

> 

> If the sector is larger, then the RAM buffer will overflow. On a read

> sector command you will overwrite whatever is past the sector buffer in

> RAM. The could be dangerous.

> 

> On a write sector command you will write whatever data is after the

> buffer to the larger sector.

> 


Weird sized sectors (along with weird sector numbers, etc.) have been a
popular device used in CoCo copy protection schemes.  Basic's BACKUP
command won't work properly with such disks.  

Art