title: the only overhead incurred by fork is page table duplication and process id creation
body: <p>The only overhead incurred by fork() is the duplication of the parent’s page tables
  and the creation of a unique process descriptor for the child. 
  In Linux, fork() is implemented
  through the use of copy-on-write pages. Copy-on-write (or COW) is a technique
  to delay or altogether prevent copying of the data.</p>
  
  <p>so why is there a need to copy page tables . as long as the processes share the pages in read only mode or until they write something there is no need that the page tables need to be copied because the translation is the same for both the parent and child??</p>
  
  <p>can someone please explain..</p>
  
  <p>thanks in advance</p>