CPU: The Computers' Brain

August 3, 2023

What makes a computer what it is?

Joseph Chisom Ofonagoro

Hardware Components of a computer

CPU: What is a CPU?

The CPU which in full is ‘Central Processing Unit’ also referred to as the main processor or simply processor is the part of every computer that performs the actual computation of instructions. For every action that is done on the computer to be complete, it must pass through the check of the CPU. Its vital function in the operation of a computer makes many computer experts to often refer to it as the ‘brain of the computer’ which it indeed is for there is no other part of a computer that does what it can do nor is capable of replacing or working without it. Its job is as simple as this: get input, process it, send output.

Brief History:

At first, when computers started to get a little bit advanced, CPUs were invented to help reduce the manual work done on computers. What need is a computer that requires more manual energy than it's meant to solve? The very first CPUs were made from vacuum tubes which are of course large and this consumed huge amounts of energy. Energy again? We can call these sets of CPUs ‘macro processors’ because they were large. As the need for mobility of computers grew, means had to be devised to make these processors smaller and that was how microprocessors came to be. These microprocessors were unlike their elder siblings, made of transistors which allowed many transistors to be on a very small chip.

What is it made up of?

The CPU is made up of two components – the Arithmetic Logic Unit and The Control Unit. Anyone who did basic computer studies in elementary school will be familiar with these terms.

Well, for the sake of those who aren't much familiar with it or have probably forgotten, the ALU controls all the logical and arithmetic operations sent as instruction to the computer. It simply handles the processing of operands and operators in a computer while the Control Unit coordinates operations of the memory & output and input.

Aside from the ALU and CU, the CPU can also be said to be made up of several other micro parts like the cache, buses and registers.

All of these parts can't be seen, they are just abstract separate entities which work as a team inside a silicon chip pinned to the Integrated circuit of a computer.

But, on the physical aspect, what are those tiny things on a CPU chip? They are called transistors, the number of transistors in a CPU determines to a large extent its efficiency. Today we have processors boasting up to 70 billion transistors, the iPhone 13, powered by the Apple A15 chip processor is said to have a whopping 15 billion transistors.

The Speed of a CPU: How is it measured?

Previously, efficiency of CPUs were measured in Hertz, but as these processors grew more advanced, a new form of speed measurement was adopted, The GigaHertz, this is why you see stuff like ‘2.0 GHz’ and the likes on your device's specification.


How Many CPUs Does a Computer Have?

Unlike us humans, computer devices are capable of having multiple CPUs or brains in a single main board.

Many contemporary devices have dual core processors, quad core processors, hexa core processors and octa core processors. Having more than a single processor allows the CPUs to share tasks among themselves making the device faster, however having a device with more processors doesn't guarantee that your device is going to be very fast, there are other factors to consider, some of them include the CPU type (this also determines the number of transistors in each core, the RAM and ROM.

So, when next you're getting a device, pay attention to both the CPU type and the number of processors.

Fun Fact: The first CPU was invented in the late 1970s at Intel, one of the largest producers of computer chip processors. As a matter of fact, the word ‘Intel’ has come to be so associated with processors that when you hear of Intel, it sounds like the name of a processor.

Now, check your device, what type of processor is there? What's the clock speed in GHz? How many cores does it have?