Floppy disks or diskettes derive their name from the flexible surface used to store information. The disk can be removed from the disk drive, so stored information can be used on other personal computers. Floppy disks generally store 1.4Mb on 3.5 inch disks. Lower capacity disks tend to be older technology. Because 3.5 inch disks are the most recent and 5.25 inch has been phased out, you should purchase 3 inch disk drives unless you specifically need access to 5.25 inch disks, e.g. you already have information stored on 5.25 inch disks.
Hard disks derive their name from the fixed metal surface used to store information.
The disks have much larger capacities than floppy disks, typically from 1.2Gb to over 5Gb plus, and come in a sealed unit so they can not easily be moved from personal computer to personal computer. The size of the hard disk drive required is determined by the total size of all programs and data you wish to store, allowing for some room for growth. Monitors Personal computers use video monitors to display information back to the operator. Monitors can either be colour or monochrome. Colour monitors are much more common now, and should be used for any but the most rudimentary computer setup.