The maximum storage capacity of the hard disk, usually measured in bytes e.g. GB.
The rotational speed of a hard disk expressed in rotations per minute. The faster the better.
Interface ports to connect pieces of equipment. USB (Universal Serial Bus) has become the most popular wired interface to connect peripherals. USB 2.0 supports speeds up to 480 Mbit/s (USB 1: 12 Mbit/s). The interface FireWire is also known as the IEEE 1394 standard. Enhanced IDE (EIDE)is sometimes referred to as Fast ATA, Fast IDE or ATA-2.