The newer FireWire version, known as FireWire 800 or 1 394b, has 9 pins. FireWire 800 can transfer information at a speed of up to 800 Mbps—twice as fast as FireWire 400—over a distance of up to 300 feet with special cabling. FireWire 800 is commonly used to connect fast external hard drives.

A Universal Serial Bus (USB) port is a high-speed port that can connect most types of devices, including a printer, mouse, joystick and MP3 player. USB can transfer information at a speed of up to 12 megabits per second (Mbps).

USB 2.0 ports, which look the same as USB ports but are much faster, are also available. USB 2.0 can transfer information at a speed of up to 480 Mbps—40 times as fast as the original USB. USB 2.0 ports can connect USB devices as well as faster USB 2.0 devices, such as an external hard drive and an MP3 jukebox.

Most internal hard drives connect to a computer through an ATA (Advanced Technology Attachment) connection, which is also known as EIDE (Enhanced Integrated Drive Electronics). ATA is available in various speeds, such as ATA/1 00 and ATAI1 33. The number indicates the number of megabytes per second (MB/s) of data the connection transfers.

A hard drive has a cache, which is an area of memory inside a hard drive where the computer temporarily stores data recently retrieved from the drive. A cache is also known as a buffer.

When a computer needs data from a hard drive, the computer first looks in the cache.

The cache can supply data thousands of times faster than the hard drive. The speed at which the platters in a hard drive spin is measured in Revolutions Per Minute (RPM). The higher the RPM, the faster the hard drive can retrieve and record data on the platters. Most hard drives have a speed of 7,200 RPM.