Sata Vs. Pata Hard Drive

Serial Advanced Technology Attachment and Parallel Advanced Technology Attachment are the names given to the two different types of hard drive interfaces. SATA and PATA hard drives transfer data at different speeds and have different capabilities. Since SATA devices were developed after PATA, SATA drives are both faster than PATA and have more features.

1. Revisions

   • SATA hard drives come in three different revisions: SATA 1.5 gigabytes per second, SATA 3Gbps, and SATA 6Gbps. Each revision offers a boost in transfer rates, although the speeds denoted in the names are the maximum theoretical throughputs and not the usual rates at which the drives will transfer data. PATA hard drives come in seven different revisions, with the last revision, Ultra ATA/133, transferring data at a maximum rate of 133 megabytes per second, as the name suggests.

   Features

   • SATA hard drives have certain features that PATA hard drives don't. If a SATA hard drive is configured to run in advanced host controller interface mode, the drive will support hot swapping and native command queuing. When a SATA hard drive is sent more than one read/write request, NCQ prioritizes the order of read/write requests to make completing the mechanical workload more efficient. On a PATA hard drive, each file is written to the hard drive in sequential order. Hot swapping enables you to switch out hard drives while the computer is on.

   Transfer Mode

   • As the names suggest, Serial ATA devices transfer data serially, or one bit at a time, whereas Parallel ATA devices transfer data in parallel -- two bits at a time. On a superficial level, parallel data transfer might seem superior to serial data transfer; it doesn't seem to make sense that transferring data one bit at a time would be faster than transferring data two bits at a time. Serial hard drives, however, run at a higher clock rate, or frequency, and can therefore send more data in the same amount of time.

   Form Factors

   • Both SATA and PATA hard drives come in 2.5-inch and 3.5-inch form factors. The former form factor is for notebooks and the latter for desktops. Although a desktop PATA hard drive can be replaced with a desktop SATA hard drive -- so long as the motherboard and power supply have the necessary connections -- a SATA notebook hard drive can't replace a PATA notebook hard drive, and visa-versa.