PROCESSOR

The central processing unit [CPU] is also called a processor. The speed of the processor is measurd in megahertz [MHz] or gigahertz [GHz]. We cannot see the CPU as it is placed inside a CPU box. A CPU is normally a 2 inch ceramic square with a very small silicon chip.

Main Memory (Primary)

RAM (Random Access Memory) is also called main memory.  RAM is used to store data and instructions that are currently being processed by a computer’s CPU. Data is temporarily stored in the RAM till it is saved to the hard disk. RAM is measured in megabytes (MB) or gigabytes (GB)

Secondary memory (Hard disk and removable storage)

Secondary storage is the memory where the information is stored permanently, till it is explicitly deleted. On power off of a computer, data on hard disk and other secondary storage devices are not erased. .The hard disk drive is the data center of the computer. .CD/DVD and pen drive are removable storage devices. 

These can be used to backup.

Input devices

An input device converts data and instructions entered using the device into a pattern of electrical signals. A user inputs data and instructions (example: using a keyboard), initiates a task (example: using a mouse), transfers images (example: using a web camera), using the input devices.

Output devices 

 An output device reverses the process, translating the binary code into a form intelligible to the user. The computer displays processed information (example: a print out of the information or audio, video) through the output devices.

Connection ports

 A port is a connection interface between the computer and other computers or peripheral devices.Some types of ports are:-

1.PS/2 Port: Used to connect the mouse and keyboard. 

2.Audio In/Audio Out: Connect various audio devices, including speakers, microphones, headsets, etc.

3.VGA Port: Monitor is connected to this port. 

4.Fan