Tip of the Day
The Hard Drive Question: ATA vs. SATA
The performance of computer systems has been steadily increasing as faster processors, memory, and video cards are continuously being developed. The one key component that is often neglected when looking at improving the performance of a computer system is – the hard drive.
Hard drive manufacturers have been constantly evolving the basic hard drive used in modern computer systems for the last 25 years, and the last few years have seen some exciting developments from faster spindle speeds, larger caches, better reliability, and increased data transmission speeds. The drive type used most in consumer grade computers is the hardy ATA type drive (commonly called an IDE drive), but now there’s the new “kid on the block”, the SATA type drive. It seems everyone wants the newer technology, and sometimes newer doesn’t always translate as better. So let’s take a look at the two.
ATA (Advanced Technology Attachment)
The ATA standard dates back to 1986 and is based on a 16-bit parallel interface which has undergone many evolutions since its introduction to increase the speed and size of the drives that it can support.
Wherever an item is referred to as being an ATA device, it is commonly a Parallel ATA device. ATA devices are also commonly called IDE, EIDE, Ultra-ATA, Ultra-DMA, ATAPI, PATA, etc. (these acronyms refer to very specific items, but are commonly interchanged)
Standard ATA drives, have the bulky, two inch wide ribbon cable with 40-pin data connections and receive the 5V necessary to power them from the familiar 4-pin connection. The basic data cables for these drives have looked the same for years.
To improve airflow within the computer system some manufacturers resorted to literally folding over the ribbon cable and taping it into that position.
The latest standard is ATA-7 which supports data transfer rates up to 133MB/sec. This is expected to be the last update for the parallel ATA standard. As long ago as in 2000 it was seen that the parallel ATA standard was maxing out its limitations as to what it could handle. With data rates hitting the 133MB/sec mark on a parallel cable, you are inviting all sorts of problems because of signal timing, EMI (electromagnetic interference) and other data integrity issues; thus industry leaders got together and came up with a new standard known as Serial ATA (SATA).
SATA (Serial Advanced Technology Attachment)
A 1-bit serial evolution of the Parallel ATA physical storage interface. SATA drives are easy to distinguish from their ATA cousins by the different data and power connections found on the back of the drives.
SATA drives, have a half inch wide, 7 “blade and beam” data connection, which results in a much thinner and easier to manage data cable. These cables take the convenience of the ATA cables to the next level by being even narrower, more flexible and capable of being longer without fear of data loss. SATA cables have a maximum length of 1 meter (39.37 inches), which is much greater than the recommended 18 inch cable for ATA drives. The reduced footprint of SATA data connections frees up space on motherboards, potentially allowing for more convenient layouts and room for more onboard features!
In addition to being more convenient to install and drawing less power, SATA drives have performance benefits that really set them apart from ATA drives. The most interesting performance feature of SATA is the maximum bandwidth possible. As we have noted, the evolution of ATA drives has seen the data transfer rate reach its maximum at 133 MB/second, where the initial SATA standard provided data transfers starting at 150 MB/second. At the onset, the overall performance increase of SATA over ATA was up 5%, but improvements in SATA technology have surpassed even that with drives now at 300 MB/second (SATA II).
Another performance benefit found on SATA drives is their built-in hot-swap capabilities. SATA drives can be brought on and offline without shutting down the computer system, providing a serious benefit to those who can’t afford downtime, or who want to move drives in and out of operation quickly.
Final Thoughts
The future of SATA holds great things for those wanting even more speed, as drives with 300 MB/second transfer rates are already available now, and by 2008 speeds of up to 600 MB/second can be expected. Those speeds are incredible, and are hard to imagine at this point. The main thing ATA has going for it right now is history, as it has been the standard for so long that it will not likely disappear any time soon. The future of SATA will be even more interesting as speed increases will help hard drive development keep pace with other key system components.
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