The hard disk drive is the main, and usually largest, data storage device in a computer. The operating system, software titles and most other files are stored in the hard disk drive.
HDD (abbreviation), hard drive, hard disk, fixed drive, fixed disk, fixed disk drive
The hard drive is sometimes referred to as the "C: drive" due to the fact that Microsoft Windows designates the "C" drive letter to the primary partition on the primary hard drive in a computer by default. While this is not a very technically correct term to use, it is still common. For example, some computers have multiple drive letters (i.e. C, D, E) representing areas across one or more hard drives.
A hard drive is usually the size of a paperback book but much heavier.
The sides of the hard drive have pre drilled, threaded holes for easy mounting in the 3.5 inch drive bay in the computer case. Mounting is also possible in a larger 5.25 inch drive bay with an adapter available at computer supply stores. The hard drive is mounted so the end with the connections faces inside the computer.
The back end of the hard drive contains a port for a cable that connects to the motherboard. The type of cable used will depend on the type of drive but is almost always included with a hard drive purchase. Also here is a connection for power from the power supply.
Most hard drives also have jumper settings on the back end that define how the motherboard is to recognize the drive when more than one is present. These settings vary from drive to drive so check with your hard drive manufacturer for details.
