Parallel ATA (PATA)

What is PATA (Parallel ATA)?

PATA or Parallel ATA refers to the specific bus interface that connects secondary storage devices such as optical drives, hard disks and others to the motherboard of a computer.

Technically, it refers to the IDE standard for transferring data as well as the cables in line with it.

Understanding PATA (Parallel ATA)

What is PATA in Computer

PATA or Parallel ATA was at first known as Advanced Technology Attachment or ATA and everything changed as and when SATA was introduced and replaced it in 2003.

PATA, back in time, referred to simply the cable that was used for different purposes on the motherboard of a computer.

Ideally, it referred to the bus interface that was used to connect the computer with different types of secondary storage devices such as hard disks, optical drives and more.

The main function of the PATA technology is to transfer data to and from the computer.

It was introduced back in 1986 by Western Digital and Compaq.

Back then, it was primarily designed to be used as a standard interface for the IBM PC-compatible computers. It was compatible with:

Hard drives
Compact Disks or CDs
Floppy Disk Drives or FDDs and
DVD of Digital Versatile Disc drives.

Ideally, the standard of PATA was sustained by the X3/INCITS committee and typically uses an Advanced Technology Attachment as well as Advanced Technology Attachment Packet Interface or ATAPI standards.

Typically, the Parallel ATA standard is considered to have evolved due to the incremental development in technology which started with the development of an AT Attachment interface.

Since then, this interface has gone through different stages of development and changes itself and has become much more powerful in comparison to the Integrated Drive Electronics or IDE interface developed by Western Digital.

As a result, there were many similar synonyms used for the ATA or ATAPI along with its earlier incarnations such as Extended IDE or EIDE and Ultra ATA or UATA were still in use.

However, after the introduction of the SATA or Serial ATA standard in 2003, the original ATA was rechristened to Parallel ATA, or in short, PATA.

The Parallel ATA cables are short, which compels to use them as an internal interface for computer storage. However, these cables could transfer data at the rate of 16 bits at a time.

Though the round parallel ATA cables were available that were easier to handle and enhanced computer cooling, only ribbon cables were used for the ATA. (More on it in the later section)

Each of the Parallel ATA cables had two or three connectors and each of these connectors came with 39 physical pins.

All these pins were arranged in two rows with a key or a gap at pin 20.

One of the three connectors was used to plug the host computer interface with the rest of the computer.

The rest of them were plugged into the storage devices such as optical disk drives or hard disk drives.

Parallel ATA Interfaces

What is PATA

The Parallel ATA came with different interfaces and each of these was not only different in design and build but also in functionalities.

Here is a brief explanation of the interface and the different connectors or pins.

Pin 20 – In an ATA standard, the pin 20 is not used. This is considered as the mechanical key. The socket of this particular key in the female connector is usually blocked. This means that the pin 20 needed to be removed from the drive connector or the male cable. This made it impossible to plug the connector in the wrong way.
Pin 28 – This pin is located at the gray slave/middle connector of the 80 conductor cable. This is usually not connected to any conductor of the cable. Instead, this is attached on the black master drive end normally and the blue motherboard end connectors. This particular pin helps in selecting the appropriate functionality.
Pin 34 – This pin is connected to the ground located within the blue connector of the 80 conductor cable. However, this pin is not connected to any conductor of the cable once again. Instead, this is connected to the gray and black connectors. This helps in easy detection of the cable.

Talking about interfaces and pins, there are a couple of variants used as well in the Parallel ATA cables.

One of these is the 44 pin variant and the other one is the 80 conductor variant.

44 pin variant – This particular type of PATA connector is normally used in the 2.5 inch drives available in the laptop computers. The connector is smaller in size physically and the pins are close to each other in comparison to a 40 pin connector. There is an additional pin in it that carries power.
80 conductor variant – The 80 conductor variant came in later when the UDMA/66 mode was introduced. Till then the PATA cables used the 40 conductor module. All of the extra conductors in this new cable variant are grounds. This reduced the side effects of the capacitive coupling between the signal conductors nearly being interleaved with them. This, in turn, reduced crosstalk.

Talking about capacitive coupling, this creates a lot of issues while transferring data at a higher data transfer rate.

Therefore, such a change was necessary so that it enabled transferring data at a speed of 66 Megabytes per second.

This will make the faster UDMA5 and UDMA6 modes work more reliably.

In the 80 conductor cables, though the number of conductors or wires doubled, the number of pins remained the same as 40 conductor cables.

However, due to the larger number of ground conductors connected to the ground pins it functioned much differently and better in comparison to the 40 conductor cables which typically had a one to one ratio of ground connectors and ground pins.

The controller in the PATA standard also helped significantly in uplifting its performance.

This is because the data split between the lanes that typically travel in parallel between the connected storage device in the master/slave configuration and the PATA controller.

The maximum speed the PATA drives could provide was up to 133 MB/s.

Sometimes, you may need to use an older PATA device in a new system that only comes with SATA cables.

In that case you should not fret because you will not have to change the entire system.

Even if it is the other way around, that is, use a newer SATA device on an old computer that supports only Parallel ATA, you can do the same as mentioned hereunder.

You will simply need an adapter to make such conversions, even if you want to connect a Parallel ATA hard drive to your computer in order to backup your files or run a virus scan.

Simply use a SATA to Molex power connector adapter so that you can connect your old computer or PATA device with the power supply.

Just make sure it uses a 15-pin cable connection.

You may also use a Molex to SATA adapter and hook it up with a SATA device with the old power supply or computer that supports only PATA devices.

Once again, in this case, make sure that it comes with a 4-pin power connection.

Or else, you can also use an IDE to USB adapter. Simply connect it to the hard drive of the computer through the USB or Universal Serial Bus.

Therefore, as you can see there is no need to panic even if you have an old computer that supports only Parallel ATA connection.

You just have to know the right way.

What Are the Features of PATA?

Now, take a look at the characteristic features of the Parallel ATA standard to gain some additional knowledge about it.

Here they are:

PATA is usually a 40 pin connector. Out of them, 20 pins are located on the upper side and the other half on the lower side. These pins face parallel to each other.
You will be able to connect up to two devices maximum with a single PATA cable.
It uses master/slave arrangement and comes with jumper settings for drive 0 and drive 1.
Only 2 bytes or 16 bits of data can be transferred through the Parallel ATA.
Operating systems of the older versions only support the PATA.

Advantages

The PATA standard offers some significant benefits to the users. Some of the major ones are:

The PATA standard is a much better choice to use with the older versions of operating systems such as Windows 95 and Windows 98, because they tend to work relatively slower as compared to the newer versions of operating systems you get these days.
Parallel ATA was the first cable connector introduced with a comparatively high speed offered in those days and therefore was in high demand among the computer users.
You can also use two devices at the same time by using only one PATA cable due to its features. One of these devices is considered to be the primary device or Drive 0 and the other one as secondary device or Drive 1.

With such benefits offered, there is no doubt that the Parallel ATA was so widely used in earlier days.

Disadvantages

On the other hand, the disadvantages of PATA are also quite significant and include:

The higher cost that made it pretty unaffordable for the average users to use it
The higher consumption of power during operation
The lack of hot swapping that did not allow replacing or changing devices without switching of the whole system when it got heated up
The shorter length of cable that did not allow a Parallel ATA device to use anywhere but within the computer casing and
The fatter cables prevented better and more convenient cable management and also reduced the airflow inside the casing of the computer which increased the temperature inside.

Typically, all these reasons along with the fact that Parallel ATA is an older technology resulted in a decline in its demand gradually and eventually being replaced by the more advanced Serial ATA or SATA standard in 2003.

What is a PATA Power Cable?

The PATA cables come with a maximum workable length of about 18 inches or 46 centimeters and are practically meant to be used with the internal drives.

The PATA cables need a power of 5 volts to operate.

Usually, the PATA cables come with a 20 by 20 matrix distribution of 40 pin connectors on either side and have a flat design.

There are two ends of these cables.

One of the ends of these cables is usually marked as IDE and is connected to the motherboard of the computer by plugging it onto a specific port.

The other end of the cable is connected to the back of the storage device just like it is done in the case of a hard drive.

There are a few specific Parallel ATA cables that also come with an extra PATA connector in the middle of it.

This is used for connecting a second device such as an optical disk drive or a Parallel ATA hard drive through the same cable.

There are actually two different types of Parallel ATA cables.

Both of these types of cables look pretty similar but are quite different in design and functionality.

Typically, these are referred to as IDE as well.

These are:

PATA 40 conductor cable – This type of cable with 40-wire design was used first to connect different PATA devices that had a data transfer speed of 33 MB/s or Megabytes per second. These cables did not allow the users to connect two devices through a single cable and was replaced later on by the PATA 80 conductor cable.
PATA 80 conductor cable – This particular type of PATA cable with 80-wire design had the ability to connect IDE devices that typically came with a data transfer speed of 133 Megabytes per second. These cables were much wider as compared to the PATA 40 conductor cables.

However, the 80 conductor cables are more efficient and capable to meet higher data transfer speed requirements and are therefore preferred more for the newer PATA storage devices.

The primary intention to increase the wire design from 40 to 80 in the PATA cables was to break through the restriction of data transfer before it hits the ceiling.

Therefore, the 40-wire design that is also known as ATA/33 was changed into the 80-wire iteration for the first time and was known as ATA/66.

This typically helped in reaching the theoretical maximum speed of data transfer of 66.6 Megabytes per second, which is double that of ATA/33.

As said earlier, both these types of Parallel ATA cables look similar due to the equal number of pins they come with which makes it quite difficult for an average user to tell them apart.

Is PATA Still Used?

Sadly, no, the PATA standard is no more in use. This is mainly because it was based on older technology and supported on the older versions of operating systems.

Moreover, with the advancement in technology, the computers systems and motherboards became more sophisticated along with the ports that used sleeker technology.

In keeping with these changes, the manufacturers looked for better solutions that are faster and more capable.

They also wanted it to match with the new technology and meet the user demands.

So, in came the Serial Advanced Technology Attachment, or Serial ATA, or simply SATA standard, and it replaced the older PATA standard successfully by the end of 2003.

In fact, today, almost all devices manufactured are designed to conform to the new Serial ATA standard.

Is PATA Same As IDE?

IDE and PATA are two different terms but people often get confused over them simply because these two terms are typically used to refer to the hard drives that are pretty much the same.

Therefore, from the perspective of hard drives, there is in fact no difference between these two terms.

The original IDE or the Integrated Drive Electronics technology used a parallel data channel to transfer data from the hard disk to the motherboard of a computer.

However, the PATA term is typically used to refer to the parallel drives.

After Serial ATA drives came into existence, though these drives use the Integrated Drive Electronics as well, they are usually not considered to be IDE drives.

Moreover, ATA or Advanced Technology Attachment is actually the official name for the IDE drive interface.

This usually means that ATA, PATA, IDE, and even EIDE or Enhanced IDE are synonymous.

Further, IDE usually refers to the PATA drives of the first generation.

In modern times however, IDE and PATA, typically refers to the similar types of hard drives that use flat ribbon-type cables.

The confusion regarding IDE and PATA seems to be due to the evolution of technology.

The IDEs are pretty different from the old hard drives because these have a more simplified and intuitive interfacing between them and the processor of the computer.

And, a part of this IDE specs refers to the interface which is called the ATA or AT Attachment and the additional letter ‘P’ refers to the parallel signaling technology.

This letter was added later on to the specs so that the users find it easier to differentiate between the newer SATA drives or technology from the older PATA drives or technology.

Moreover, the PATA interface later on has been modified to use flash cards, for example Compact Flash Cards, to keep things simple.

Though this needs a larger power source and is not very suitable for using the flash cards due to its standard form, such modifications made to the hardware of the drives reduces the physical connection.

Apart from that, such modifications also provide a separate power source to it which resolves the problem at hand.

The confusion between the IDE and PATA also exists irrespective of the fact that IDEs are now long obsolete and the PATA standard is also on its way.

Still, the PATA technology is even used today even if the SATA standard has replaced it long before.

This is because the older computers still use this drive since they are not compatible with using the SATA drives.

Conclusion

So, now you know what PATA or Parallel ATA is and also know that this hard drive type is hardly used nowadays.

These are similar to Integrated Drive Electronics and Enhanced Integrated Drive Electronics and are the first hard drive that connects the hard drives to the computer through a PATA interface.