IMO, this depends on the type of data being collected. But I would say that for a single "chunk" somewhere around 256 mb would probably be a good starting place since your board only has 512 mb of memory for both the OS and your program.What should I use as the size of buffer to save the data from memory to a file on the USB drive?
You could start by simply piping the results of "df" (disk free) to your program or a file. And don't forget that you have a 4gb EEMC memory "card" built into the hardware.Is there a way to query the USB drive to get the size?
I doubt that the actual version will make much difference, and you should be able to upgrade the OS after you obtain the hardware.I am just starting and the Debian version is working on being updated; not sure if I will wait till after the upgrade or use the current version.