Decoding kryoflux stream for HP9895A

Eric Smith spacewar at
Sun Sep 25 03:32:34 CDT 2016

On Tue, Sep 20, 2016 at 7:42 AM, Denise de Vries
<denise.devries at> wrote:
> Does anyone know of documentation for the HP9895A format with its own M2FM encoding?
> I have a kryoflux preservation stream but so far can make no sense of it.

On Wed, Sep 21, 2016 at 12:59 AM, Christian Corti
<cc at> wrote:
> I've already written a decoder for the HP 9885/9895 format. Denise already
> sent me his image, but I haven't had the time to try decoding it yet...

Denise sent me the image as well.

dfitoimd has now been renamed to fluxtoimd, as it now supports both
DiscFerret and KryoFlux image input. I've partially added HP M2FM
format; it now correctly decodes the address fields, but I have a bit
more work to do on the data fields. I expect to have it completed

> - 0xD0: ECC data address mark

Any idea how they use that? Aside from that being included in the list
of address marks in the service manuals, it's not described at all.
Since the 7902/9885/9895 don't do ECC, perhaps it was reserved for
future use.

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