Program logic controllers are used to control the operation of most systems.

Snarled program logic is unstructured logic, also known as "spaghetti" logic. Compiled machine code is the ultimate example of snarled program logic. Although spaghetti code is more compact and efficient than structured code, it is extremely difficult to both comprehend and maintain. Hence we use structured programming languages to provide a high level of abstraction between the logic of the programmer and the snarled logic of the machine-dependant code.

An error in the logic of a program means that the output of the program is faulty (eg the program tell you 2+2=5). An error in semantics in a program means that the program statements are not constructed properly and the usual result of this is that the program will not compile.

Snarled program logic is unstructured logic, also known as "spaghetti" logic. Compiled machine code is the ultimate example of snarled program logic. Although spaghetti code is more compact and efficient than structured code, it is extremely difficult to both comprehend and maintain. Hence we use structured programming languages to provide a high level of abstraction between the logic of the programmer and the snarled logic of the machine-dependant code.

Apple Logic Studio is a commercial program, so you will have to buy it, or get a job at Apple.