Parallel ATA (Parallel Advanced Technology Attachment or PATA) is a standard for connecting hard drives into computer systems. As its name implies, PATA is based on parallel signaling technology, unlike serial ATA (SATA) devices that use serial signaling technology. Parallel ATA dates back to the 1980s. Integrated Drive Electronics (IDE) drives operate according to this standard. Parallel ATA norms permit link lengths up to just 18 inches (46 centimeters). As a result of this length restrict the innovation ordinarily shows up as an interior PC stockpiling interface. For a long time ATA gave the most widely recognized and the slightest costly interface for this application
The connections for PATA devices were originally made using 40-conductor ribbon cables. These were later supplanted by 80-conductor cables in which every other conductor is grounded, minimizing mutual capacitance (and consequent crosstalk) between conductors. The maximum workable cable length is 46 centimeters (about 18 inches). This means that PATA cables are only practical for use with internal drives.
Parallel ATA was originally called Advanced Technology Attachment (ATA) until the year 2003 when SATA was introduced. The cable for a SATA connection has seven conductors. These cables are more flexible than PATA cables and can be much longer, allowing the designer more latitude in the physical layout of a system. Because there are fewer conductors, crosstalk is less likely to be troublesome in SATA than in PATA. The signal voltage is lower as well (250 mV for SATA as compared with 5 V for PATA).