title: Using user-buffered I/O for File operations
body: <p>I am a newbie to system programming please mind me if my doubt is very vague.</p>
  
  <p><em>I read that inbuilt user-space buffers are used so that we can access block sized data through a system call via the kernel which takes a huge over head but in the user-space we can make minute access to small  sized data.I understood how this method is efficient but what i did not understand is,since these user-buffers are pertained to each single process that opens the file.</em></p>
  
  <p><strong>How will a process recognize the minute changes that are made to a file when both are simultaneously accessing the file.</strong></p>
  
  <p><strong>Does this not create a problem as processes will access the old data but not the data that is changed by some other process which is still in the user-space buffer.</strong></p>
  
  <p>Please mind me if any mistakes.</p>