Configuration:
The "total state" of the Turing machine: tape contents, tape head position,
and state.
Initial
Configuration:
The
initial tape contents are the input.
The tape head
position - e.g. on the leftmost non-blank (or anywhere if the tape is
all blank).
Initial
state.
Choosing
an Instruction: At each step, any instruction that matches the current
state and currently read symbol can be executed. Executing an instruction
leads to a new configuration.
Halting:
If no instruction applies, then the Turing machine halts.
Output:
The contents of the tape in the halting configuration
