Week 2-Session 2-Motherboard,CPU & Main Memory

The System Unit

The system unit is the carrier case of the electronic components. This is the black box of the computer which include processor, memory, expansion cards and most storage devices. It’s just like our head which carries our brain which is protected by a skull.

What’s inside the system unit?

• Processor
• Memory module
• Expansion cards

-Sound Card

-Modem Card

-Video Card

-Network interface card

• Ports and connectors

Motherboard

Motherboard is let’s say something like the kidneys of the computer.It is the main circuit board of the system unit. It contains chips, integrated circuits and transistors. A motherboard can also be known as the system board of the computer.

Processor

The processor is the most important part of the computer. Just like our brain. It processes the data and controls the computer. It’s normal to have one processor in each PC. But powerful computers used as servers have more than one processor. The data transfer between the processor and memory is done through the system bus. Each part of the memory has its own memory address and the processor determines where processed data is stored by sending an address signal along an address bus and data along a data bus.

Central Processing Unit

CPU is the processor + memory. Sometimes, the processor is called the CPU. It takes all major decisions, makes all sorts of calculations and directs all parts of the computer functions by activating and controlling the operations. Megahertz (MHz) is a measure of a CPU’s processing speed or clock cycle in millions per second.

The main functions of the CPU includes;

• Converting data into information
• Acting as the control center for the computer
• Executing stored program instructions

The central processing unit is divided into two as;

• Control unit (CU): This part of the CPU communicates with other parts of the hardware. It directs the computer system to execute stored program instructions.
• Arithmetic & Logic unit (ALU): Performs arithmetic operations and performs logical and relational/comparison operations.

Main memory

There are two types of memory. RAM (random access memory) and ROM (read only memory)

• RAM: It holds the program instructions and the data that is being used by the processor. RAM is volatile which means it looses its contents when power is turned off.
• ROM: This holds the program instructions and settings required to set up the computer. ROM is non-volatile which means that it does not loose its contents when power is turned off.

So these are the basic ingredients for a computer to perform its basic tasks. No other hardware component can take the place of any of these three components because the functions performed by these three components are unimaginable. And if you purchase a computer that weighs around 1000 kilos, you pay half of the price for the little CPU which weighs only around 50 grams.