Are direct system call functions the fastest way to read/write data on Linux?

[TasostGreat]

I'm trying to write a program which reads a file really small size with two number and a character and ouput another file which can have up to 120.000.000 characters. is unistd equal to direct system call function? and if yes is it the fastest way to read/write data on Linux.

[TasostGreat]

do these direct system call functions exist and if yes what are those. I haven't found anything but i am sure i have read something about that.
please help thanx in advance

[Salem]

Did you learn anything from your previous thread?
http://www.daniweb.com/forums/thread168362.html

Or are you going to show us what you've tried?

Or are you just going to keep repeating the same refrain until you get bored, or we magically stumble on an answer which you like the look of, even if it's wrong?

[TasostGreat]

if you have noticed i am not making the same question there is a difference

do these direct system call functions exist and if yes what are those.

in the previous thread i added a last question which is not replied

Originally Posted by Narue View Post

My educated guess is that as far as the vanilla solutions go, iostreams will be the slowest, followed by stdio, then unistd

ok i see
is unistd equal to direct system call function? i am sure i've read something about that and it's beeing faster but i am not sure. i've made a search but it has been fruitless

all around is to make the question more clear

i don't intend to bother you with the same questions
again thanks for your replies