[Open-graphics] A possible dataset file format for the PCI analyzer - version 2

[Dieter]

We could just take whatever binary format gets uploaded from the
OGD and put that into a file.  Handle demand paging by having
a file for each page, probably with the starting sample number
in the filename.

If the simple compression provided by the capture logic isn't as
compact as a more complex compression scheme can provide, use gzip
or bz2 or whatever.

If a single file is desired, make a tar archive or write a converter program.

If another file format is desired, write a converter program.