dfitoimd: decoding Intel M2FM floppy flux images (was Re: Intel 432 floppy flux images for decoding)

Chuck Guzis cclist at sydex.com
Mon Aug 8 14:19:46 CDT 2016

On 08/08/2016 11:56 AM, Eric Smith wrote:

> If you're willing to share the code, I'd be interested in taking a
> look.

I'll see what I can do to come up with something.  It's going to be

> Is there any documentation about AES MMFM format online?

Not that I know of--heck, I can't find any documentation on the original
machine as it is.  I had to "brute force" that one; complicated a bit by
the bit order being backward (i.e. USART order, not floppy order).   To
date, I still don't know what the machine model is--just have the floppy
written by some journalist back in the 70s.

> Typo in the part number?  The WD9914 is WD's second source (or
> clone?) of the TMS9914 GPIB chip.
> I was able to find some info on the internals of the SMC FD9216 data 
> separator. WD second-sourced that as the WD9216.

Yeah, that one--brain fart on my part--I was looking at the WD data comm
products book, which looks just the same as the storage management
products book and picked out what I thought was the data separator.

Regardless, I'd like to see what the 9216 details are.  I suspect it's
nothing more than a counter-based data separator, but it's remarkable
for how well it works.  Shouldn't be hard to incorporate into an FPGA or
even a CPLD.




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