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Power Over eSATA could replace USB as the port of choice for external drives

Mobile computer users often find that ultra portable computer systems lack optical drives and use hard drives that are smaller than what might be ideal for the sake of portability and longer battery life. Often the best thing these types of users can do is use external optical drives and external HDDs that are connected via USB.

While the USB interface is practical, it isn’t always the fastest interface for transferring large amounts of data. The preferable connection type for moving large amounts of data is via SATA and eSATA ports. These ports are common on virtually all modern computer systems and SATA is used for both storage devices as well as optical drives.

The Serial ATA International Organization (SATA-IO) announced it plans to have a new specification ready this year called Power Over eSATA (PDF) that will provide power to external optical and storage drives via the eSATA connector. The goal of the specification is to not only provide power to a device over SATA, but to maintain the much faster 3GB/s data throughput. SATA-IO says that products using Power Over eSATA could be available on the market by the second half of 2008.

"Its [SATA's] fast transfer rate and efficient protocol makes eSATA the highest-performing external mainstream storage connection,” said Knut Grimsrud, SATA-IO president and Intel Fellow. “Enhancing eSATA with power delivery will provide a new level of convenience to the designer and the end user. By eliminating the need for a separate power connection, customers can more easily expand their storage, making Serial ATA an even more attractive solution for mainstream storage applications.”

With the additional bandwidth and power-over-bus, eSATA could easily replace USB in several applications outside of storage.

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USB 3.0
By TomZ on 1/16/2008 10:14:06 AM , Rating: 3
eSATA + Power will have to compete with USB 3.0 which is currently in development:

http://en.wikipedia.org/wiki/USB#USB_3.0

It has 10X the bandwidth of USB 2.0, backwards compatibility with previous versions of USB, and has power-conserving protocols.

The latter point addresses one of the minor design problems with SATA, which is that it consumes a relatively large amount of power.




RE: USB 3.0
By kelmon on 1/16/2008 10:47:27 AM , Rating: 2
I have to confess to favoring FireWire over USB for external storage devices since the real-world performance tends to be much better. USB's theoretical maximum throughput is definitely higher compared to what you actually get to the point that even basic FireWire 400 is faster than USB 2.0. It will be interesting to see what USB 3.0 really delivers but I'm skeptical for the moment as I don't honestly believe their numbers.


RE: USB 3.0
By noirsoft on 1/16/2008 11:14:44 AM , Rating: 2
The problem with Firewire is that most if not all PC manufacturers only put 4-pin firewire ports on laptops, which do not provide power. Not Firewire's fault, to be sure, but still a good reason why many prefer USB devices.


RE: USB 3.0
By kelmon on 1/17/2008 2:44:00 AM , Rating: 2
That I can understand and it's obviously the manufacturer's fault for being, well, cheap. Without using FireWire on a "normal" PC it is hard for me to comment further beyond to say that I can use my LaCie hard drive with my MacBook Pro with just the FireWire cable but my father, who bought a relatively generic PC, needs to use 2 USB ports to power the Maxtor OneTouch Mini that he acquired at Christmas. Both drives use a 2.5" hard drive so I was honestly shocked that Maxtor needed to use 2 USB ports to draw enough power (well, Maxtor calls the 2 plugs Data and Power). In retrospect we did not try to use the drive with only a single plug but then this isn't the sort of thing to experiment with if the drive is supposed to be containing backups of your important data.


RE: USB 3.0
By Visual on 1/16/2008 12:41:08 PM , Rating: 2
most pcs have just a single (if even that) firewire port though, and while there might be splitters or hubs available (i don't know) that is a bit inconvenient. usb ports on the other hand are already plenty.

either way, usb was meant for low-bandwidth applications, and something new like esata is really needed these days.


RE: USB 3.0
By TomZ on 1/16/2008 1:05:19 PM , Rating: 1
quote:
usb was meant for low-bandwidth applications

Incorrect - 480Mb/s (2.0) and 4.8Gb/s (3.0) is hardly "low-bandwidth." It just happens to be that SATA is currently faster, until USB 3.0 comes out.


RE: USB 3.0
By Visual on 1/17/2008 6:27:18 AM , Rating: 2
3.0 doesn't exist yet, 2.0 is obviously lower than a hard drive so not enough for storage. also, on many implementations this figure is the total combined bandwidth for all ports on a controller, so individual devices get even less bandwidth.
and when i said what you quoted, i wasn't even referring to a specific figure - just the original purpose of the usb bus.
it was meant for your mouse, keyboard and joypad, a printer/scanner and low-res webcam, and definitely not for fast removable storage. it was intended to replace the lpt, com and game ports, not the ide controller on your mobo.
even though the second version made it somewhat more adequate for external storage, it is still not enough, and the original purpose of the bus is still more obvious.
as to version 3.0 - we'll see if it is as good as promised. i certainly hope so


RE: USB 3.0
By dcalfine on 1/17/2008 12:26:25 AM , Rating: 2
I'm going to go ahead and agree there. I don't want to launch a USB vs. FireWire war (especially in a thread devoted to eSATA) but the latter really has a great architecture. The next revision of the IEEE 1394 standard will reach 3.2Gbps and maintain bus power (which, currently, allows a much higher wattage than USB and allows for the daisy-chaining of devices.)

For some reason eSATA always seemed awkward to me. I made the jump from PATA to the recessed connectors of the Mac Pro. It seems flimsy and cheap, though I'm well aware of its technological advantages.

What about networking over eSATA?


RE: USB 3.0
By gramboh on 1/16/2008 11:18:25 AM , Rating: 2
I wonder what the overhead will be like with USB3. With USB2, although the theoretical max is 480mbit/s (60mbyte/s) I never see over 30-35mbyte/s using an external drive in a USB2 enclosure (7200rpm). Using eSATA on a similar drive I see the same transfer rates as using the drive in my PC (almost double). I assume this is because of interface overhead.


RE: USB 3.0
By Ray 69 on 1/16/2008 4:59:08 PM , Rating: 2
If I'm not mistaken, the theoretical max of 480 Mb/s is actually 48 MByte/s not 60 MByte/s. I know that a byte is 8 bits but USB is a serial connection so you would have to add 2 bits to your calculation, a start and stop bit (same applies to SATA connections). Still though you seldom see it near the max except for the rare burst spike.


RE: USB 3.0
By TomZ on 1/16/2008 5:42:08 PM , Rating: 2
For USB, the overhead is actually quite a bit more complicated than that. The 10-bit rule applies to 8b/10b encoding used for SATA, but USB doesn't use the same encoding. Instead, USB uses different size checksums (CRCs) on different fields within the packets.


RE: USB 3.0
By retrospooty on 1/16/2008 11:49:02 AM , Rating: 2
Not really. all eSATA I have seen have USB2 as well, no reason to think the next gen enclosures wont do the same with eSATA+power and USB3. Both will be around for a long time.


RE: USB 3.0
By Etern205 on 1/16/2008 3:29:56 PM , Rating: 2
What's the point of being faster if it cannot sustain it's transfer rate?

USB 2.0 is 480Mb/s while Firewire A is 400MB/s but
firewire has a better sustain transfer rate than USB which
is why most video editing users perfer firewire over USB.

For eSATA it's indeed faster, but for sustain transfer rate
how is it?


RE: USB 3.0
By saiga6360 on 1/16/2008 8:02:21 PM , Rating: 2
I'm guessing the same as an internal drive, which would be pretty normal.


RE: USB 3.0
By mikeyD95125 on 1/16/2008 10:04:47 PM , Rating: 2
The article says 3GB/s but isn't SATA 3 Gbps ? Hate to be a nitpicker but it is a pretty big difference.


RE: USB 3.0
By dcalfine on 1/17/2008 12:28:56 AM , Rating: 2
no, you're right
3GB/s would be an unprecedented feat.


RE: USB 3.0
By B166ER on 1/17/2008 2:19:51 AM , Rating: 2
Not at all nitpicking. The confusion between MB and mb is a huge deal in my book. Its unit of measure and can create a bit of war if not understood. Imagine your ISP selling 6MB/s cable, and you getting 6mb/s? Get what you pay for? To this day I still see hardware sellers, network companies, even the occasional "computer guy" screw this up to almighty hell. Funny thing is, when I comment on its incorrectness, I'm lamblasted for being picky. Go figure.


Question
By BansheeX on 1/16/2008 10:57:20 AM , Rating: 2
Can someone explain to me why we need two different formats for external devices and internal ones? Why not just have USB 3.0 for everything?




RE: Question
By masher2 (blog) on 1/16/2008 12:27:00 PM , Rating: 2
Probably for the same reason shoe stores sell more than one size. No one interface is good for the wide range of possible users and usages.


RE: Question
By TomZ on 1/16/2008 12:39:51 PM , Rating: 2
I disagree - the proposed USB 3.0 would meet most/all of today's known requirements for a serial interface. It would do anything that eSATA and FireWire can currently do, and be faster at the same time.

And I think having a single port standard benefits consumers because there is no splintering effect that causes designers to have to "waste" cost and space on additional connection types.

I do recognize, however, generally that competing standards are helping to keep these standards improving.


RE: Question
By BansheeX on 1/16/08, Rating: 0