Limited time: 4TB Seagate external hard drive, USB 3.0 for $139.99

Michael Santo's picture
Amazon.com

If you need a ton of external storage for your videos, images and more, Rakuten (formerly Buy.com) has a deal for you: a Seagate Expansion 4TB USB 3.0 External Hard Drive for only $139.99 after coupon code.

Once activated, the deal includes free shipping. However, Rakuten charges sales tax in many states: California, Connecticut, Illinois, Massachusetts, New York, Tennessee, and Washington. The coupon code for the deal which can be found here, is 515EA12. It expires on October 11. There is a limit of five per order.

In comparison, Amazon.com is selling the same drive for $149.99, or the same price as Rakuten without the coupon code being added.

It is nice to see a low-cost external drive with a USB 3.0 option attached to it. The prices of many external hard drives have dropped -- or been dropped via a deal -- but in most cases the drives have been USB 2.0 drives, the earlier -- and much slower -- standard.

Comparing the two standards,,USB 2.0 was released in April of 2000. Its maximum signaling rate of USB 2.0 is only 480 Mbit/s; which was speedy then, but is no longer, what with Apple's Thunderbolt I/O and USB 3.0, as well. USB 2.0's effective throughput is "up to" 35 MB/s or 280 Mbit/s. Once USB 3.0 was released, theUSB 2.0 standard became called "Hi-Speed."

USB 3.0 was released in November of 2008. It has received the new "SuperSpeed" mode labels and has a signalling rate of up to 5 Gbit/s. Its usable data rate of is "up to" 4 Gbit/s. It is backwards compatible with USB 2.0, as you would expect, but lags in speed behind Apple's Thunderbolt I/O, which more than doubles the that speed, with a 10Gbit/s Thunderbolt bandwidth per channel.

Like Firewire, an earlier standard that Apple embraced which fell to the monolithic USB standard, Thunderbolt allows for daisy-chaining of devices. It can also be used as a display interface.

To address that slower data rate, a January 2013 press release from the USB standards group revealed plans to update USB 3 to 10 Gbit/s to put it on par with Apple / Intel's Thunderbolt I/O port speed by mid-2013. It's unclear when USB 3.1 will reach the market, though.

The slow adoption of USB 3.0 -- evident by the proliferation of devices still being released with USB 2.0 capability -- will probably mean a similar slow adoption for USB 3.1, in any case.