The hard drives in laptops and desktop computers store data using electrical charges. These charges come from platters that spin inside the drive. Each platter has thousands of subdivisions called sectors. Each sector can accept an electric charge that corresponds to a binary number (1 or 0). The software in the CPU and motherboard tells the read/write head where to move on the platters. The drive reads the sectors and turns them into 1s or 0s that are used to store data. The storage devices in most laptop and desktop computers use an electromechanical technology called SATA, while more expensive servers use SCSI or fibre-channel drives with faster interfaces.
The Serial ATA International Organization (SATA-IO) oversees the technical specification for SATA. It succeeded parallel ATA (PATA) as the hardware interface for most new computer systems, but many also support SCSI and nonvolatile memory express (NVMe) technology.
SATA is a serial-attached storage technology that uses thinner, more flexible cables than PATA's ribbon cables. It supports hotplug, native command queuing and advanced features. The ATA command set allows the host to identify device capabilities and support hardware control features, including queued TRIM commands that reduce solid-state drive power consumption.
Pin 11 is sometimes used (usually by chassis or backplane hardware independent from the SATA host connector and its data connection) for staggered spinup, activity indication and emergency head parking. The feature can draw power, so it must be disabled in systems designed to operate at speeds of 1.5 Gbit/s or below. In those systems, a jumper-switch can be used to force the drive to operate at a speed of 1.5 Gbit/s negotiated by the system.
