Chapter 6
Alan Turing
British Logician, mathematician Turing Award very prestigous Homosexual
UTM
Can have input of abstract turing machine Functionally equivalent if M1 halts for some input and M2 also halts for same input
Three components of a digital computer and draw it
Control -> gates/flags ->databse -> memory bus -> memory
Digital Computers
Discrete State Machines Manipulate Letter Strings
Uncomputable Functions
Halt Check, all computable functions are turing-computable
Input of UTM two parts
Software (Description of the machine table for the TM being simulated) Data: input for the TM being simulated
Two Key Ideas of UTM
Stored programs in a formal langauge Simulation
Von Neumann Machines
TM has one register VNM has many TM has linear access memory NVM has addressable memory Modern cpu has many instruction increment, add, jump
Enigma Machine
World War 2 Third Reich Electro-mechanical rotor machine FSM
Bombe Machine
codebreaking for enigma machines