Parts of the Computer CPU

By John Landers

Each of the parts of the computer CPU (central processing unit) has a specific function to perform. The components work in unison, and collectively, they formulate the "intelligence" behind the computer. The central processing unit reads instruction sets, interprets them, executes the instructions and sends out results. The CPU has the "brains" to perform computations and convey information from one area to another. It makes decisions, and determines the next step to take, based on the conclusions it makes.

Function

The central processing unit is called the CPU, processor or microprocessor. Modern processors are engineered on just one computer chip. The CPU is the device that receives various types of input and produces specific outputs. The majority of processors are capable of carrying out a single instruction at a time. However, the one instruction is executed at lighting speed. In fact, most personal computers have the capacity to perform directives in less than one-millionth of a second. Powerful supercomputers can execute commands in less than one-billionth of a second.

Control Unit

The various parts of the computer's CPU are directed by the control unit. The control unit can be described as the manager of the CPU. It is comprised of electronic circuits that utilize electrical pulses to transmit signals to other components of the computer. The control unit instructs them to perform, or keep application commands. Its sole purpose is to guide other mechanisms in the system to complete specific tasks. The CU talks with the ALU and memory.

ALU

The arithmetic logic unit (ALU) is one of the most important parts of the computer's CPU. It's comprised of electronic circuits that make it capable of executing arithmetic and logic operations. It works with different registers to store data or hold information about the latest action performed by the logic unit. The ALU has the ability to perform four types of arithmetic operations: addition, subtraction multiplication and division. The ALU also has the means to perform three kinds of logic comparisons: equal-to, less-than and greater-than. The ALU is capable of comparing letters, numbers or special characters. The personal computer then takes action based on the results of the comparison. An example of such a comparison would be the following "less-than" operation: If the average test score of a student is less than 70 percent, then the student receives a "fail" grade; otherwise, the grade is "pass."

Registers

Registers are temporary memory devices that are indispensable parts of the computer CPU. They are managed by the control unit. Registers are used as storage areas that contain data and other information that are often needed while a program is running. They are meant to be to be accessed very quickly. There are different types of registers, including instruction registers and test registers. The instruction register contains the instruction the CPU is currently executing. The test register is used to hold the results of calculations performed by the CPU.

Clock

Another component that is included in parts of the computer CPU is the clock. The clock is made of timing circuitry that measures the timing of tasks performed by the CPU in terms of clock cycles. The performance of processors is generally measured by the clock rate or clock speed of the CPU. In theory, a higher clock speed means that the CPU can execute instructions (cycles) faster. The clock speed is measured in "hertz." Hertz refers to the quantity of clock cycles per second. A CPU with a speed of 1 GHz would mean that it performs one billion clock cycles per second.