Re: Questions on Disk ][ error checking

[Toinet <antoine.vignau@laposte.net>]

On 11 nov, 22:15, dog_...@macgui.com (D Finnigan) wrote:
> I have a question about the error-checking mechanism used on the Disk ][.
>
> As I understand it, checksums are used to verify that the data read from the
> disk are valid and error-free. However, would there be a way to skip these
> checks? Is there any software that does so?
>
> I ask because I have more than one disk which has some data and programs
> which can be read successfully, and some data which cannot. These disks are
> not copy-protected. Would it be worth my time to make a disk image of a disk
> with only partially good data? Is this even possible?
>
> Also, would there ever be a circumstance where the disk has become damaged
> in an area such that the Disk ][ cannot tell whether a bit is 1 or 0 and
> thus refuses to read that disk?

If you have a DOS 3.3 RWTS disk, B942:18 is your friend ;-)

Go to brutal-deluxe.fr / Products / Apple II / Disk Copiers, download
the image, use Advanced Demuffin 1.4 which does the job of copying
disk even with read errors (ensure that addres B942 is correctly set
to 18)

Or use Ron's technique...

antoine