With continuous development of faster processors, memory and video cards, the functioning and speed of computer systems is rapidly improving.

One crucial component, which is often overlooked when looking the efficiency of a computer system is the hard disc. The manufacturers of hard drives have been continuously evolving the basic hard drive, which is used in modern computer systems for the last 25 years, and in the recent few years, some major developments have happened in this field, including faster spindle speeds, larger caches, enhanced reliability, and superior data transmission speeds.

Also known as IDE drives, ATA hard drives are primarily used in consumer grade computers. Originated in the year 1986, the ATA standard is based on a 16-bit parallel interface and has undergone many developments since its introduction to improve the speed and the size of drives, which it can support. The latest in this category is ATA 7 (first introduced in 2001 by the T13 Technical Committee, which is responsible for ATA standard) that supports supports data transfer rates up to 133MB/sec. ATA 7 is This is likely to be the last update in the journey of evolution for the parallel ATA standard.

During 2000, it was observed that the parallel ATA standard was reaching out its limits as to what it can handle. With data rates continuously hitting the 133 MB/sec mark on a parallel, several problems may arise because of the signal timing, EMI (electromagnetic interference), and various data integrity issues. Because of this various issues, industry leaders got together and developed a new standard, which was known as Serial ATA (SATA). SATA has been around for only a few years, but is destined to become the standard because of its various advantages over the ATA standard.

 

Basic Differences -

ATA	SATA
Originated in 1986	Originated in 2000
16 bit parallel interface	1 bit serial evolution of the parallel ATA physical storage interface.
ATA standard has undergone many evolutions over the years with latest version as ATA – 7.	Still in its yearly age and has not undergone much changes.

Basic Features & Connections
SATA drives can be easily distinguished from their ATA cousins because of the several data and power connections found on the back side of drives. Some of the differences between the features and connections of ATA and SATA drives are -

ATA

SATA

Standard ATA drives, such as a 200GB Western Digital model, are somewhat bulky with 2 inch wide ribbon cable and 40-pin data connections and get the 5V essential to power them from the 4-pin connection. The primary data cables for ATA have remain the same for years. With the introduction of ATA-5 model, a change was made to improve the signal quality by making use of an 80 wire cable on the 40-pin connector (these are generally known as the 40-pin/80-wire cables). To improve the flow of air within the computer system, some manufacturers designed it by literally folding over the ribbon cable and fixing it into that position. Another recent change in physical design came with the development of rounded cables. The functioning of the rounded cables have found to be equal to that of the flat ribbon, however many generally prefer it because of the improved system air flow, ease of wire management, and cooler appearance that come with them.

SATA drives, such as a 120GB Western Digital model, have a half inch wide, 7 blade and beam data connection that makes it a much thinner and easier to manage data cable. The cables of a SATA hard drive have a maximum length of 1 meter that is much greater than the advocated 18 inch cable for ATA drives. The reduced footprint of data connections in a SATA drive frees up space on the motherboards, thereby providing for more convenient layouts and room for more on board features. SATA drives receive the essential 250 mV to power them from a 15-pin power connection. 15-pins for a SATA device looks like it would require a much larger power cable than a 4-pin ATA device, however, in reality the two power connectors are just about of the same height. At present, many SATA drives are also coming with a 4-pin power connector for convenience.

Nowadays, many modern motherboards, are coming with SATA drive connections on board, and new power supplies that usually feature a few of the essential 15-pin power connections, which makes it easy to use these drives on new systems. Older computer systems can easily be upgraded to support SATA drives by use of adapters, such as a PCI slot SATA controller and a 4-pin to 15-pin SATA power adapter. Optical drives nowadays are also becoming more promptly available with SATA connections.

Performance
In addition to being more convenient to install and drawing less power, SATA drives also offer several performance benefits, which really set them apart from ATA drives.

An important performance feature of SATA drives is the maximum bandwidth possible. As we have seen, the technological evolutions of the ATA drives have resulted in the data transfer rates reaching its maximum at 133 MB/second, while the current SATA standard provides data transfers of up to 150 MB/second. The overall improvement in performance of SATA over ATA can presently be expected to be up to 5%, (according to hard drive manufacturers), however improvements in SATA technology will surely improve on that.

The future of SATA holds great things for those wanting even more speed, as drives with higher data transfer are expected to be developed over the next few years.

In addition, SATA drives have found to be more beneficial in their built-in hot-swap capacities. These drives can be brought on and offline without the need for shutting down the computer system, thereby providing a major advantage to those who cannot afford downtime, or people who want to move the drives in and out of operation quickly.