Hard drive This is hiding inside your computer and is where all your data is stored when you save it. You may never see it unless you open up your computer to fix a problem. The picture below shows a 40 gigabyte (the size or capacity) hard drive, 7200RPM (the speed or revs per minute).
Cd rom Drive This is where you put a cd rom disk in. It could be a drive that can also read and write on cds or DVD disks.
Floppy drive This is the smaller drive that takes those little plastic square shaped disks. They are rarely used now as they are no longer needed for a boot disk if you have a cd rom.