Turing Machine - Hardware
The Turing machine can be imagined as something like a typewriter, but having the additional quality of being able to read, or scan, other symbols, and to erase them if necessary. Turing settled on the idea of a tape of infinate length, divided into squares, with each square carrying a single symbol. The machine would then move the tape one square at a time, read the symbol, and then either remain at the same state, or move to a new state , depending on what it read. In each case its response would be purely automatic, and determined by the contruction of the machine. The machine would either leave the symbol alone , or erase it and type another, then move the tape by one square and continue. Essentially the Turing machine is simply a device for transforming one string of symbols into another string according to a predetermined set of rules.