Alan Turning Machine or Model

What is Turing Model or Turing Machine in Computer Science? A Complete Definition…

Hey guys, I am again back with a new post that is on Turing model. Have you heard it the first time? Yes? Oh, that why you are here dude. Let me brief it to you as easy as I can…

Firstly, its just an idea, an idea of making a universal device or machine to perform all the computational works. This idea is firstly presented by Alan Turing in 1937. When this machine took its space or get invented, then it is named as Turing Machine or Turing Model.

Basically, Turing loves to or we can say he is more interested in giving philosophical definitions of computation than building such a computational machine. His idea of making such a machine, changed our world drastically, no doubt.

Before getting more deeply into the Turing model, let me tell you about data processors, I mean to say, computer as a data processor. Using the definition of Turing model, the computer acts as a black box, that accepts the data as input data (I/p data) -> Process the data as a processor -> finally creates the results as an output data (O/p data). It will be more clear after the following diagram.

Turning Model - Single Purpose Computing Machine

The problem in the above model is that it doesn’t specify the type of processing. Means, how many processes can be processed in the model at one time. Is it a specific or general-purpose machine.

I would like to tell you that it’s only a specific purpose model. And this is designed to do a single job. Confused? e.g. Controlling some readings like temperature, fuel, etc. But nowadays the computer works on a general-purpose machine.


A Turing Machine is a mathematical model. Turing Machine or Model consists of an infinite length tape. This infinite tape is further divided into cells on which input is given. It consists of a head which reads the input tape and state register stores the state of the Turing machine.

When the head read an input symbol then it is replaced with another symbol which results to its internal state change, and then it moves from one cell to the other (Rightward or leftward direction). If the Turing Machine reaches the final state, the input string is accepted else it will be rejected.

A Turing Machine can be described as seven tuples (Q, X, ∑, δ, q0, B, F) which represents −

  • Q as a finite set of states
  • X as tape alphabet
  • as input alphabet
  • δ as transition function; δ : Q × X → Q × X × {Left_shift, Right_shift}.
  • q0 as an initial state
  • B as a blank symbol
  • F as a set of final states

More updates coming soon…

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