and bios9.bin : ARM7 and ARM9 processor instructions. firmware.bin : The boot instructions for the hardware.
In the context of melonDS, nand.bin is a complete dump of a Nintendo DSi's internal flash memory. It typically contains: The DSi Home Menu and system settings.
It isn't an apple, it isn't a pear, It’s the Nandbin Melonds, exceedingly rare. They look like a pumpkin but shine like a coin, With a smell that is spicy, like pepper and join.
For DSi enthusiasts, melonDS is clearly the top choice, especially regarding NAND-based features and active development.
Installed DSiWare and system applications (like the DSi Camera or Shop).
Virtual eMMC flash storage containing the system menu and titles.