title: What is the performance overhead for fseek?
body: <p>Is there any performance overhead of <code>fseek</code>? E.g., does a <code>fseek</code> call actually asks the kernel to move disk head?</p>
  
  <p>Also, does <code>fseek</code> performance cost have anything to do with how "far" it seeks? E.g., fseek(1byte) v.s. fseek(100Mb) v.s. fseek(end-of-file).</p>