Parallel ATA (PATA)

Definition of PATA (Parallel ATA)

PATA, short for Parallel ATA, is an IDE standard for connecting storage devices like hard drives and optical drives to the motherboard.

PATA generally refers to the types of cables and connections that follow this standard.

It's important to note that the term Parallel ATA used to simply be called ATA. ATA was retroactively renamed to Parallel ATA when the newer Serial ATA (SATA) standard came into being.

PATA connections
Archimerged / Wikimedia Commons / Public Domain

Even though PATA and SATA are both IDE standards, PATA (formally ATA) cables and connectors are often referred to simply as IDE cables and connectors. It's not a correct usage but it's very popular nonetheless.

Physical Description of PATA Cables & Connectors

PATA cables are flat with 40-pin connectors (in a 20x2 matrix) on either side.

One end of the cable plugs into a port on the motherboard, usually labeled IDE, and the other into the back of a storage device like a hard drive.

Some cables have an additional PATA connector midway through the cable for connecting yet another device, like a PATA hard drive or an optical disk drive.

PATA cables come in 40-wire or 80-wire designs. Newer PATA storage devices require the use of the more capable 80-wire cable to meet certain speed requirements. Both types have 40-pins and look nearly identical, so telling them apart can be difficult. Although usually, the connectors on an 80-wire cable will be black, gray, and blue while 40-wire cable connectors will only be black.

More About PATA Cables & Connectors

ATA-4 drives, or UDMA-33 drives, can transfer data at a maximum rate of 33 MB/s. ATA-6 devices support up to 100 MB/s speeds and might be called PATA/100 drives.

The maximum allowable length of a PATA cable is 18 inches (457 mm).

Molex is the power connector for PATA hard drives. This connection is what extends out from the power supply for the PATA device to draw power.

Cable Adapters

You might need to use an older PATA device in a newer system that only has SATA cabling. Or, you might need to do the opposite and use a newer SATA device on an older computer that just supports PATA. Maybe you want to connect a PATA hard drive to a computer to run virus scans or back up files.

You need an adapter for those conversions:

PATA Pros and Cons Over SATA

Since PATA is an older technology, it only makes sense that most of the discussion about PATA and SATA will favor the newer SATA cabling and devices.

PATA cables are big compared to SATA cables. This makes it harder to tie up and manage the cabling when it's laying over other devices in the way. On a similar note, the large cable makes it harder for the computer components to cool down since airflow has to make its way around the bigger cable, something that isn't as much of a problem with slimmer SATA cables.

PATA cables are also more expensive than SATA cables because it costs more to manufacture one. This is true even though SATA cables are newer.

Another benefit of SATA over PATA is that SATA devices support hot-swapping, which means you don't have to shut down the device before you unplug it. If you need to remove a PATA drive, it's necessary to actually shut off the entire computer first.

One advantage that PATA cables have over SATA cables is that they can have two devices attached to the cable at one time. One is referred to as device 0 (primary) and the other device 1 (secondary). SATA hard drives just have two connection points—one for the device and the other for the motherboard.

One common misconception about using two devices on one cable is that they will both perform only as fast as the slowest device. However, modern ATA adapters support what's called independent device timing, which lets both devices transfer data at their best speed (of course, only up to the speed supported by the cable).

PATA devices are supported by really old operating systems like Windows 98 and 95, while SATA devices are not. Also, some SATA devices require a certain device driver in order to fully function.

eSATA devices are external SATA devices that can connect to the back of the computer with ease using a SATA cable. PATA cables, however, are only allowed to be 18 inches long, which makes it extremely difficult if not impossible to use a PATA device anywhere but inside the computer case.

It's for this reason that external PATA devices use a different technology like USB to bridge the distance.

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