anden88 wrote:If I want to sell a product that containes Rasp Pi B+ then can I simply duplicate the SD card and put the duplicated SD cards with my program files and everything into new Rasp Pi B+ that i buy. And it will work?
Or will I have to reinstall Raspian on every new Rasp Pi B+ that I buy.
Another words, can a duplicated SD card directly work on any new Rasp Pi B+ if I just simply plug the SD card in.
in principle if you have a card that contains the latest version of the boot & "PI-bios" files then the combination of them will be compatible with any pi. any differences between PI's will be resolved by the equivalent off a "BIOS", that is part of the files loaded at boot, they take care of the possible differences, by detecting the model of PI they are running on, and then making suitable changes to correct those differences. For example there are PI's with different brands of SDRAM that need different operating parameters, the "PI-BIOS" takes care of that, also the B+ needs to generate a 25 MHz clock signal that on a B+ is used to clock the LAN/ETHERNET chip, earlier versions used a dedicated 25MHz crystal to do that.
Getting a SD-card replicated may sometimes be a problem, as no SD-card has exactly the same size, as lots of them have "bad flash sections", so every card has a different size, in fact some aftermarket (I mean "fake") cards simply increase card sizes by pretending that dodgy sections are "fine", and program the card's controller to use them and report the larger capacity.
it's enlightening to watch this: http://media.ccc.de/browse/congress/201 ... _xobs.html
The correct way to duplicate cards is to resize them so their size becomes smaller than the smallest expected size.
This can be done with a partition manager, which converts unused space into "free and empty space" by shrinking the partition.