Significance

• The CPU is also called the microprocessor or processor. It is actually an electronic component that can carry out specific instructions or computer programs. Most computations take place in the processor. Larger computers may have more than one processing chip. Typically, desktop and notebook computers contain only one microprocessor. The two most prominent inner parts of the CPU are the arithmetic logic unit (ALU) and the control unit (CU). There are also other components, such as register arrays and buses.
  
  

Control Unit

• The control unit (CU) is the inner part of the CPU that directs the actions of the microprocessor. The CU transmits pulses to other parts of the processor giving instructions on the next step. This process is referred to as the machine cycle. It involves the following activities: get the instruction from main memory, decipher the instructions, transfer the information and carry out the instructions. The control unit has its own set of internal components that helps it perform its responsibilities, such as the decoder, and clock and control logic circuit for producing signals.
  
  

ALU

• The arithmetic logic unit is the part of the microprocessor that performs mathematical calculations and logic operations. It works with different registers, such as the accumulator and flag registers. The ALU performs typical operations including addition, subtraction, multiplication and division. It also make logic analysis and make comparisons, such as "less than" and "equal to" functions.
  
  

Registers

• Another inner part of the CPU is the registers, which are small memory containers. The instruction register (IR) keeps the instructions the microprocessor is currently deciphering and processing. The information held in IR is maintained in order to keep the CPU from losing time by going to the memory position repeatedly. When instructions and information is taken from memory and other places, it is placed in the memory buffer register (MBR).
  
  

Bus

• The bus is the inner part of the CPU that provides a path for communication between some devices and the system's microprocessor. There are basically three types of buses: 1) data bus, 2) control bus and 3) address bus. The control bus oversees the different actions of the computer via signals transmitted from the CU that is located within the central processing unit. The data bus handles the movement of information back and forth, along different wires, connecting the microprocessor, RAM and other hardware. An address bus transmits signals, such as the particular address of the cell where the CPU must read or write data.