Re: ADTgs issues

[Linards Ticmanis <ticmanis@gmx.de>]

Alex Freed wrote:

>> Michael, I always wondered if DOS3.3 and ProDOS disks were essentially
>> formatted in the same way.
> 
> Yes at some level: the physical format of the sectors is mostly the same
> (apart from interleaving). However
> ProDOS treats pairs of sectors as 512 byte blocks.

No, the interleaving is the same (namely none) on the physical sector
level. The sector numbers in the sector headers on the disk increase in
steps of one on every track.

The two systems both renumber the physical sectors into logical sectors
in two different ways, and ProDOS additionally treats pairs of sectors
as logical blocks, but all that has nothing to do with the low-level format.

Only DOS 3.1 / 3.2, i.e. 13-sector disks, use physical sector level
interleaving; on the other hand, they don't do any logical renumbering
of sectors.

The only difference in 5.25 inch low-level format between DOS 3.3 and
ProDOS disks is that DOS 3.3 disks are usually formatted with a volume
number of 254 (but this is changeable), while ProDOS uses volume number
1 (not easily changeable).

-- 
Linards Ticmanis