Original URL: http://www.theregister.co.uk/2009/03/20/usb3_esata/
eSATA: A doomed stopgap?
The kiss of USB 3.0 death
Comment The external SATA (eSATA) interconnect is merely an interim idea and the coming of USB 3.0 will kill it off, according to Verbatim's EMEA business development manager Hans Christoph Kaiser.
The background is that eSATA, running at 3Gbit/s (around 300MB/sec), is meant to connect external disk drives to PCs using the SATA protocol. Currently most external drives are connected by USB 2.0 running at a pedestrian 480Mbit/s. USB, the universal serial bus, is a general external device interconnect for PCs and notebooks, encompassing thumb drives, digital cameras, web cams and external hard drives.
Since USB was first mooted and made available, the capacities of external disk drives have rocketed and transferring multi-GB files between a PC and a 1TB SATA drive can take a long, long time. Speeding this up was the obvious eSATA benefit. It was first conceived of at SATA 1 speed, 1.5Gbit/s, and then developed to eSATA 2 running at SATA 2's 3.0Gbit/s.
In January 2008 the SATA-IO  group said it would extend the specification to have the connecting Power Over eSATA cable deliver power to the external device as well as carry data. Such a POeSATA standard is still not here, meaning eSATA devices continue to need a separate power cable.
Seagate and AMD have just demonstrated a working 6Gbit/s SATA 3 interconnect, but there is no news yet of any corresponding eSATA 3 specification. Seagate sources suggest we won't see SATA 3 devices in much use before 2011, so that gives plenty of time for the SATA-IO group to react.
There's no question that eSATA is very much faster than USB 2.0. However, most PCs and laptops don't come with a built-in eSATA port and the internal electronics to connect it to the PC's bus. It costs money to do this, and keeping the cost of goods down in the cutthroat PC/notebook markets is crucial for supplier profitability.
High-end products, like Dell's Adamo, do boast an eSATA port. Solid State Drive suppliers like Transcend and Buffalo have added eSATA ports to some of their SSD products. Still, none of these are bread-and-butter products.
You can have a DIY eSATA setup by installing a special card in your PC which provides an eSATA port, such as the Promise SATA300 TX4302 . Then you buy your external drive with an eSATA port, such as a Seagate FreeAgent Extreme, purchase an eSATA cable and away you go. It's just not convenient.
So along comes USB 3.0, rated at around 4.7Gbit/s, say 470MB/s, which will leapfrog SATA 2's speed and be backwards-compatible with current USB 2.0 and 1 devices. We can expect stand-alone USB 3.0 controllers by the end of the year and the first USB 3.0 products in 2010. It seems inevitable that product manufacturers will switch USB ports on their products to USB 3.0 very quickly.
Kaiser said that manufacturers switched from USB 1 to USB 2.0 virtually instantly, and Verbatim intends to switch to USB 3.0 with its own external hard drive products as soon as it's available.
By the end of 2010 there will be hundreds of products using the USB 3.0 interconnect as standard and very few using eSATA as standard. Isn't it likely that, to save component costs, manufacturers will ditch eSATA ports and rely just on USB 3.0?
FireWire's spread was severely cramped by USB 2.0, with Apple focusing on USB interconnects instead of FireWire. I think we can foresee a repeat of this pattern with USB 3.0 and eSATA taking FireWire's role. When USB 3.0 arrives who will need eSATA and how will its expense be justified? Ditto S3200 FireWire. That's a coming 3.2Gbit/s FireWire format due later this year. It's a niche play surely.
It looks as if Kaiser is right - eSATA is strictly an interim standard that will be blown away by USB 3.0. FireWire is a niche interconnect and eSATA is an interim one with both failing to achieve USB's universality because they don't have its widespread manufacturer and customer adoption, and have never achieved a sustainable competitive advantage. USB 3.0 will give both of them a lip-smacking kiss of death. ®