Re: Backing up Pascal Disks...

[Rubywand <rubywand@swbell.net>]

"John B. Matthews" writes ...
> 
>  Rubywand <rubywand@swbell.net> wrote:
 ....

> >      One possible snag with using ADT is that, transferring to PC,
> > you end up with a .dsk file. A .dsk file usually
> > has DOS 3.3 sector ordering; but, it can be in DOS 3.3 
> > or ProDOS order. The emu is supposed to figure out which.
> > That could be a problem with a Pascal disk.
> 
> Don't ProDSOS and Pascal disks have the same logical block order?
> 
 ....

     Pretty sure they do use the same ordering on 5.25" disks.

     The problem could be with order used for encoding/decoding of the disk
image. ADT is always going to use DOS 3.3 sector ordering to arrange the data
in a disk image it creates. To come up with a correct read of the disk image,
the emulator needs to use DOS 3.3 ordering.

     A ".dsk" disk image does not specify ordering. The emu has to decide-- for
instance, it could check the contents of a few sectors and make a pretty good
guess about ordering if it figures it's dealing with a standard DOS 3.3 or
ProDOS disk.

     If the emu does not include Pascal in its checking, it might decide the
.dsk is garbage and reject it. Or, it might somehow default to ProDOS ordering.

     Changing the disk image suffix to ".do" tells the emu: "This image uses
DOS 3.3 ordering". That should avoid any confusion about reading a Pascal disk
image created by ADT.



Rubywand