eSATA External Hard Drives
I'm getting ready to buy an external hard drive for backups, but I'm confused by all the terminology when it comes to connecting the drive. Should I go for USB, Firewire, or eSATA? What are the pros and cons of each?
What is eSATA?
eSATA stands for External Serial Advanced Technology Attachment. It is a standard for a connector between a computer and an external device, such as a hard drive or CD/DVD drive. Similar standards include USB (Universal Serial Bus) and Firewire. The thing about eSATA is, it's faster than any other common external device connector.
An eSATA connection transfers data up to four times faster than USB 2.0 or Firewire 400. In the real world an external drive using a USB 2.0 interface will reach data transfer speeds of 20-30 MB/sec, versus up to 300 MB/sec for eSATA. Additionally, some features of SMART drives may not work over USB or Firewire, but they will on eSATA.
An eSATA port is not standard equipment on all computers. If your desktop computer does not have an eSATA port, you may be able to add one in the form of a card you plug into a peripheral control slot on the computer's motherboard. Laptop users can add eSATA ports with Cardbus or Expresscard cards.
The eSATA Power Problem
If eSATA is so much faster, then why don't we see eSATA on every computer and external device?
The main reason is that an eSATA link cannot supply power to an external device, as USB or Firewire can. Therefore any external device connected via eSATA needs its own power supply. That limits eSATA in competition with USB and Firewire when it comes to the size and portability of devices that can be used with it. You won't see an eSATA thumb drive, for example.
But for external CD/DVD drives, a power supply is necessary no matter what link to the computer is used. So an eSATA external drive makes sense if you want the fastest possible data transfer, as in backup/restore operations of copying large files for physical transport to another location.
You can use a cable up to six feet long with an eSATA connection. That's long enough for most purposes, but if you need a longer cable you will have to use USB or Firewire. When buying an eSATA cable, be aware that it is not configured the same as an internal SATA cable, and an internal SATA cable's plugs will not fit eSATA ports on your computer or external drive.
The Future of eSATA
Whether SATA will ever add the ability to supply power to an external device is unclear; it's on the agenda of the standards body that develops the SATA standard, but products that incorporate "power over eSATA" are slow coming to market.
In the future, eSATA ports will become more common on desktop and laptop computers as vendors add this feature to compete with one another. Also, the SATA standard, internal and external, will continue to improve in speed. The SATA 6Gb/sec standard will double the transfer speed of the current SATA-II spec. Look for eSATA devices based on this new standard to arrive in soon.
In 2010, expect to see a battle royale between supporters of eSATA and USB 3.0 technology. The emerging USB 3.0 products promise data transfer speeds rivaling that of the new SATA 6Gb/sec standard, without the need for external power. Toss in Firewire 3200, and we're likely to see continued confusion in the marketplace. The most likely scenario is that vendors will offer external drives that offer all three connectors.
Got something to say about eSATA drives? Post your comment or question below...
This article was posted by Bob Rankin on 3 Dec 2009
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Article information: AskBobRankin -- eSATA External Hard Drives (Posted: 3 Dec 2009)
Copyright © 2005 - Bob Rankin - All Rights Reserved