Re: EDD Plus Card

["Michael J. Mahon" <mjmahon@aol.com>]

On Nov 20, 8:39 am, "Payton Byrd" <pay...@paytonNOSPAMbyrd.com> wrote:
> "vladitx" <vlad...@nucleusys.com> wrote in message
>
> 19db0a76-e5ea-4515-ad6b-68c41cd2a2dd@d61g2000hsa.googlegroups.com">news:19db0a76-e5ea-4515-ad6b-68c41cd2a2dd@d61g2000hsa.googlegroups.com...
>
>
>
>
>
> > On Nov 19, 11:40 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
>
> >> Capturing (even fractional) tracks from a protected floppy is only
> >> part of the problem of recovering its data.  There was a *long*
> >> thread regarding the representation of protected floppies over a
> >> year ago, IIRC.
>
> > Sooner maybe.
>
> > Yes, capturing by sampling is easy. The real problem is analyzing the
> > data. Somewhere in the middle is the choice of representation that
> > will be both simple yet effective (and just enough). My definition of
> > simple/effective ratio covers pure software implementations (e.g.
> > emulators on PC), pure hardware (emulators on FPGAs and the likes) and
> > mixed (e.g. emulators of diskettes done with MCUs and some helper
> > circuitry).
>
> >> Although I still favor the .FDI format, I don't think that the current
> >> size and "vigor" of the Apple II community would support establishing
> >> a new "standard" image format for protected disks, and the emulators
> >> and utilities to make them useful.
>
> > Recently I am spending some time on the problem and so far have setup
> > of a simple board with MCU that controls directly the Disk ][ drive
> > and samples the data for many rotations. Sampled stream is sent via
> > USB to PC. Capturing DSK-style images is done already as a trivial
> > task, but some analysis is being worked on. Final goal is making
> > images (like Disk2FDI) but tuned specially and only to the Apple2.
>
> Have you guys looked at mnib and the G64 format for archiving Commodore 1541
> floppies?  These guys have managed to capture entire disks at the GCR level
> and store that raw data along with the logical file system in the G64
> format.  You can use a G64 to write back an exact copy of the original disk
> on a 1541, including all of the subtle errors and inconsistent behavior that
> a lot of copy protection was based on.- Hide quoted text -
>
> - Show quoted text -

Does the C64 allow real-time fractional track stepping while reading?

The variability of the completely software-formatted Apple II 5.25"
floppy
is, IMHO, greater than any other comparable drive permits.

-michael