help needed regarding ke*il...
It's not a "simple" question.
It's really a "great" one.
But it's hard to explain in several words.
I think u could refer to some open-source code for printf/sprintf. To understand how the arguments to be relayed, how they to be interpreted,
finally, the most complicated, how a character was transfered to a interface between hardware and software.
And more, if u want to know the hardware to deal with a "character", u need more knowledge about many hardware device. Behide "file system" there're a large amount hardwares, such as uart/usb/ata/sdram/ram/NandFlash... Aha... who knows how many : )