Re: My laser 128

[Antoine Vignau <antoine.vignau@laposte.net>]

On 10 jan, 20:52, Michael J. Mahon <mjma...@aol.com> wrote:
> D Finnigan <dog_...@macgui.com> wrote:
> > Bill Hicks wrote:
> >> On Jan 10, 1:07�am, Michael J. Mahon <mjma...@aol.com> wrote:
>
> >>> Exactly. There was a short window when "single sided" disks were actually
> >>> single sided.
>
> >>> And Apple's method of formatting is more tolerant of isolated surface
> >>> imperfections than others.
>
> >>> -michael - NadaNet 3.1 and AppleCrate II:http://home.comcast.net/~mjmahon
>
> >> When you init a disk does dos do any verification?
>
> > From reading some documentation on ProDOS, I got the impression that the
> > ProDOS Filer utility does make an attempt at marking out bad blocks so that
> > they won't be used to store data.
>
> Nope. A disk either formats or it doesn't--there is no mechanism for
> altering the track capacity.
>

Correct for track capacity.
But what prevents Filer from reading blocks after a format and mark
out bad blocks? That means that Filer won't stop on I/O while
formatting though.

> When formatting track 0, if it does not read back correctly, the track will
> be reformatted in a different rotational phase, which can bypass isolated
> media faults if they fall in sync areas.
>
> After a certain number of retries, it gives up.
>

For my knowledge, from where did you get that information, Michael?

> -michael - NadaNet 3.1 and AppleCrate II:http://home.comcast.net/~mjmahon

Thank you,
antoine