syscall

Gentlemen, I am trying to understand the magic of syscalls. In C, everything is not very complicated. I tried to do this-fran ... Still after the call syscall the error code is located in the eax register. Tell me, please, what am I doing wrong? Thanks.

What does fflush do? Many people write that this function gives the OS a command to reset the contents of the buffer to disk. ... implemented by the program itself, and not by the OS? And when you call write, the data will be immediately written to disk?

Please help, I can not deal with syscall in any way. I know WinAPI functions because I have already worked with them (With mo ... ol for example RemoveDirectoryA, describe in more detail or suggest articles preferably in Russian, I will be very grateful.