[rrd-users] RRD and Respironics Smart Card

Simon Hobson linux at thehobsons.co.uk
Tue Apr 22 20:06:41 CEST 2008

Chris wrote:

>Granted, there is the possibility that the .bin file is
>not using Tobias Oetiker's algorithms.
>But why would Respironics reinvent the wheel?

Why wouldn't they ? There are many reasons : having a proprietary 
format that isn't readable with other tools might be a design goal; 
not using anything 'tainted' with an open licence might also be a 
requirement; just plain "we know better" attitude; not knowing about 
rrdtool; not running a system suitable for running rrdtool - so 
there's a few options for you, the list is by no means complete.

>Respironics' smart card system is younger than RRDTool.

So ? rrdtool does not have a monopoly on fixed size circular buffer schemes.

>Others on my preferred list about cpap machines have suggested
>the likelihood that the file is some form of rrd.
>I suspect its encrypted and/or compressed.
>I'm looking for suggestions or pointers about how to unlock and
>dump such a file. Any help will be greatly appreciated.

Detective work is needed.

I'd be surprised if it was encrypted as this would make updates 
unneccessarily complex and processor intensive.

So, hexdump the file and take a peek - try and figure out what format 
it's in. You can do the same with an rrd file and compare - the 
difference being that you can make custom rrd files, and experiment 
with inserting known data into them (and I imagine that Tobi probably 
has a file spec somewhere).

That's probably as much help as anyone on this list can give you.

More information about the rrd-users mailing list