An internal hard drive is a hard drive that resides inside the computer. Most computers come with a single internal hard drive, which includes the operating system and pre-installed applications. While laptop computers only have room for one internal hard drive, some desktop computers have multiple hard drive bays, which allows for multiple internal hard drives.
Internal hard drives have two main connections – one for data and another for power. The data port may have an ATA or a SATA interface. This interface connects to the computer's hard drive controller, which enables the drive to communicate with the motherboard. The power connector attaches to an electrical cable, which provides power from the computer's main power supply.
The internal hard drive is a key component of a computer since it stores the user's software and personal files. While the rest of a computer's components can be easily replaced, if a hard drive fails, the data may not be able to be recovered. Therefore, it is wise to regularly back up the data stored on an internal hard drive using an external hard drive or an online backup service.