If you are building a computer from the ground up or upgrading an existing one, then you're likely to encounter different kinds of physical disk technology. The type of drive you have installed will determine its maximum transfer rate. A hard disk drives writes data to a series of disc-like objects called platters. These platters have thousands of subdivisions that can all accept an electrical charge. The actuator arm or read/write head is instructed by the CPU and motherboard to move over these sectors and record their corresponding charges as 1s or 0s.
Until 2000, mechanical hard disk drives were interfaced to the computer with a special parallel port called PATA (Parallel Advanced Technology Attachment). The bulky connector required a 40-pin or 80-pin cable, which limited the maximum transfer rate to 133 MB/sec. PATA drives were replaced by Serial ATA, or SATA, which operates at the same raw data rate of 1.5 GB/sec but allows each connected device to use all of this bandwidth without sharing it with any other devices, as was true of PATA.
SATA has also eliminated the need for the 40-pin or 80-wire ribbon cable by replacing it with a thinner, 7-wire version. This reduction in cable thickness eases cable routing and allows better air flow and cooling of the disk drives. SATA also uses a lower signaling voltage and pin density than PATA, which further increases data transfer rates. It also requires no external power supply, which saves space and money on the chassis. In addition, it uses SATA-specific power-saving features that can increase drive lifespan by up to 30%.
