Inside a computer

In the previous lesson, we learned what the basic parts in the computer are. In this topic we are going to see how the computer’s inside looks like and it’s main parts.

Motherboard

The motherboard is a circuit board. This act as the backbone of the system. All the other internal and external parts are connected to the motherboard directly or indirectly. It holds the Central Processing Unit (CPU), Memory, connectors for the hard disk drive and optical drives and two or more slots for expansion cards to control audio and video. In addition various connections to computer’s ports (such as USB ports, Ethernet port, FireWire ports...Etc.)

CPU/Processor

This is the brain of the computer. Central Processing Unit or Processor is located on the motherboard inside the computer case. It’s main duty is to execute commands. Whenever you press a key on the keyboard, click the mouse button, run an application, you are sending instruction to the CPU. Then the CPU passes the control instruction to other devices indicating things what they have to do.

The CPU is a 2x2 inches ceramic square with a silicon chip. This chip is approximately size of your thumb nail. And CPU is covered by a metal cube called heat sink which absorb the heat from the CPU.

A processor speed is measured in Hertz. Today’s processor’s speed are measured in GHz (Giga Hertz). Or billion instructions per second. Faster processor executes instructions more quickly. Processor speed is directly impact to the overall speed of the computer. However actual speed of the system will depend on the speed of many other components.

RAM (Random Access Memory)

This is the main memory of the system. RAM is a volatile memory which means data in the RAM will be disappeared or erased when the power is off. This short-term memory keeps data / information whenever computer perform calculations until it is needed.

When you are working on a spreadsheet, designing graphic, or typing a document, you must save them regularly to avoid losing those data. Saved data will be stored inside the Hard disk drive which is the main long term memory.

Size or capacity of the RAM is measured in megabyte (MB) or gigabyte (GB). If more RAM your computer have, more things your computer do at the same time. If the computer does not have sufficient memory capacity you can notice that your computer stuck while few application are running at the same time. However it is possible to upgrade the RAM capacity by adding extra RAM to the computer.

ROM (Read only memory)

This is a non-volatile permanent storage which keeps hard coded program that allows the computer to start up.

ROM can perform large input/output (I/O) tasks and protects program and software instructions. Data written in the ROM cannot be erased. Following are the some types of ROMs.            

• Ultraviolet-erasable ROM (UV-ROM) - ROM whose contents can be erased using ultraviolet light, and then reprogrammed.
• Erasable programmable ROM (EPROM) - A type of ROM that is programmed using high voltages and exposure to ultraviolet light for about 20 minutes.
• Electrically-erasable programmable ROM (EEPROM) - Often used in older computer chips and to control BIOS, EEPROM can be erased and reprogrammed several times while enabling the erase and writing of only one location at a time. Flash memory is an updated version of EEPROM that allows numerous memory locations to be changed at the same time.

Hard drive

This the place where your documents, audios and videos are stored. Hard disk drive is long term storage which means data in the hard disk will keep remains even the computer is power off. When you run a programs necessary data in the hard drive will be copied to the RAM. When save a file data in the RAM will be copied back to the hard drive. Faster hard drive can increase the efficiency of a computer.

Power supply unit

This is to convert power (coming through wall outlet) to the power needed by the computer. Power supply sends power through cables to the main circuit board and to other components.

Expansion cards

Most motherboard have two or more Expansion cards slots to connect different Expansion cards. Sometimes called PCI (peripheral component interconnect) cards. However you may never need PCI cards since most motherboards have built-in video, audio, network, and other capabilities.