C-map charts on SD card

[Norman_E]

I just received my chart covering all of the Mediterranean & the Black Sea. It is on a single SD card. At the price they are I worry about data loss, especially as the plotter is capable of writing to an SD card or even formatting it, or theft of the card from the plotter.

It is not possible to store just the bit of chart in current use within the plotter, so the card has to left in. Does anyone know if it is possible to copy just a portion of the chart data to a user card for use in the plotter, and then keep the expensive chart card safe elsewhere?

 

[prv]

Does anyone know if it is possible to copy just a portion of the chart data to a user card for use in the plotter, and then keep the expensive chart card safe elsewhere?

Why copy just a portion, why not copy (if it's possible) the whole thing?

Surely the best way to find out would be to just try it?

Pete

 

[Mistroma]

I've yet to find anything that can't be copied if it is worth the effort. However, that doesn't mean you will be able to copy it easily.

I have no idea what, if any, copy protection is used but no harm in trying to make an "image" of the card (as suggested in previous post). It seems reasonable that the C-Map files will be protected (otherwise you'd just be able to make multiple copies). However, I'd be surprised if the protection was as simple as writing some data to an area outside the actual file (I was using that method about 30 years ago, so not exactly cutting edge).

So not much real help as there are many ways of providing copy protection (such as the more modern methods like CPRM). Perhaps someone else has knowledge of a workaround.

 

[Mistroma]

I had a quick look for information on C-MAP on SD Cards when I got back home. I found a reference to CPRM for this data and that's bad news as far as copying. It must have been around 10 years ago when I found out that SD-Cards were being built with this as an integral part of the hardware. This means that the data is encrypted for that specific card and the key to read it won't work on another card. At least that's what I remember.

I haven't kept up with this area since retiring so don't know the latest position on cracking but you won't be able to get around this encryption.

I remember that the US authorities policed DRM so rigorously that people wouldn't even discuss how to crack it (even theoretically). Didn't work of course and it was possible to get around it after a few years and strip it out of videos. It wouldn't surprise me to find that CPRM can also be by-passed but I'm certain that it would involve some very specialised kit.