This is the main unit of computer, which is responsible to perform all the operations. The CPU of the IAS computer consists of a data processing unit and a program control unit.
The data processing unit contains a high speed registers intended for temporary storage of instructions, memory addresses and data. The main action specified by instructions are performed by the arithmatic-logic circuits of the data processing unit.
The control circuits in the program control unit are responsible for fetching instructions, decoding opcodes, controlling the information movements correctly through the system, and providing proper control signals for all CPU actions.