"Peter" wrote in message
...

so that the PC software can write to it in a simple manner. I don't
know what is involved but can tell you that if you plug one of these
into a normal reader and invoke the windoze API call for reading
physical sectors, all you see is rubbish; mostly zeroes. It looks like
they are using some odd property of the flash chips, but that would
lead to rapid obsolescence.

No odd property of the flash chip at all. Just a low level data structure
that makes no sense to the Windows drivers trying to interpret it as a
device that supports a filesystem.

It is entirely feasible to write a Windows driver for a Jepp datacard. You
would bypass all of the Windows drivers and be writing a very low level
device interface.

I'm just glad they still support data updates at all. Pay the $150 and enjoy
the updated data in your GX55.

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Travis
Lake N3094P
PWK