title: Is a Turing machine a real device or an imaginary concept?
body: <p>When I am studying about Turing machines and PDAs, I was thinking that the first computing device was the Turing machine.</p>
  
  <p>Hence, I thought that there existed a practical machine called the Turing machine and its states could be represented by some special devices (say like flip-flops) and it could accept magnetic tapes as inputs. </p>
  
  <p>Hence I asked <a href="https://stackoverflow.com/questions/7366085/how-input-string-is-represented-in-magnetic-tapes">how input strings are represented in magnetic tapes</a>, but by the answer and by the details given in my book, I came to know that a Turing machine is somewhat hypothetical.</p>
  
  <p>My question is, how would a Turing machine be implemented practically?  For example, how it is used to check spelling errors in our current processors.</p>
  
  <p>Are Turing machines outdated?  Or are they still being used?</p>