Hard Drive & SSD
A hard drive is the disc inside the monitor which holds all of your files, music and internet in your computer. An SSD is the smaller, lighter, faster and newer version of the hard drive. The SSD is used in iPads Phones and smaller lighter computers whereas the hard drive is used in older computers. The HDD is slower, older, heavier and will break easier but it is alot less expensive and will hold more data.
A Samsung SSD
This one is lighter and faster but more expensive and will hold less data.
This one will hold more data but is heavier and slower.
SSD's are used in Macbook airs and other newer computer's.
The optical drive is the slot on the side of the computer which will hold any discs you put in like DVD's CD's and any type of disc. Any disc you put in will then come up on your screen. You can put games and blu ray discs in it. It will read the disc's dataand show it on the screen.
The monitor is the bit at the back of the computer that holds the HDD or the SSD. Without the monitor the computer would be nothing. The monitor also holds the optical drive, so the monitor is a necessity for the computer.