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Why Powered USB Is Going to Fail
An anonymous reader writes "Patrick McFarland, famous Free Software Magazine author, has written a two part article about why Powered USB is not taking off at home. (part 2 is also available) He includes a lengthy history on why USB took off in the first place, and then continues on to explain what we gain by allowing Powered USB to power all our devices."
Agreed.I've never been a big fan of USB. The concept is fantastic, a unified connector that links just about any device to any other and can charge them is a great idea. However I am still bitter the Firewire lost out. It has more bandwidth, has sturdier connectors, and can deliver far more power. Being able to just plug one cable to power and link a hard drive would be great, I have one of those external IDE enclosures, and having *another* power brick is just silly.
Being able to charge high draw devices through Firewire would rock. Powering my laptop from my PC would be great, especially if it will be syncing files at the same time, allowing me to leave the power brick in my laptop case and not have to get it out after getting home.
In my eagerness to get this post in first, I didn't read the article before I started typing. He says it all the same way I would. So to all of you who haven't RTFA'd, do it to find out the rest of this comment's points. Now lets see if I can still get this in first...
I hate printers.
I love the idea of those USB power strips. Imagine being able to power your notebook off of one! That could end the different power brick for every notebook mess.
On USB 2.0 vs. FireWire400/800: I know that this subject as been beat to death, but anyway... Higher speed are always nice, but I am not often limited by the bus speed. What I LOVE about USB is that the specification is open. Anyone can download it. You can build your own USB gizmos in your basement; no large investment is required. There are plenty of chips that support USB available in small quantities (like 1 or 2). You can even make USB look just like a serial port, making said gizmos compatable with LABView with no driver fuss. Try that with FireWire! Now if I could make all my little lab gizmos powered off the USB bus as well, heck, I might never go home.
I know FireWire is popular for video transfer, but isn't that what DVI is for? For data transfer, you don't have to run DVI in real time, and you can run 3.9 Gbits/sec over DVI today.
... to succeed: For the same reason there is are NO standards for external power bricks for laptops/printers/scanners/hubs etc. Because there is a high margin add-on market from manufacturers to replace proprietary power devices (when lost) with expensive branded units which are probably about 5x to 10x the cost of what generic units would if there was a some common defined types (V/ma/connector-types) which would be universal. A move to efficent USB power would undercut this business in the same way, so the only standard that will be agreed upon will be an unworkable one. Firewire never replaced USB because it had licence encumberences (cost more to use), alas.
If you'd have bothered to read the article carefully, you'd see that "Powered USB" is a different standard then USB 2.0 (which is what your Sansa uses), with different cables and higher power output. "Regular USB" is fine for powering small devices, like your Sansa. Powered USB is meant to power big devices, like printers, scanners, external hard drive enclosures and optical drives. (Sure, the minority of external hard drive enclosures are powered by USB 2.0, but it isn't recommended, which is why most enclosures have external power supplies).
This guy is proposing that ALL peripherals, big and small, should be powered by Powered USB, thus eliminating the multitude of power cords and bricks that go with all your computer peripherals.
Where do compatibility problems come into play? The Powered USB spec has three kinds of plugs, depending on the voltage supplied (5, 12 or 24).
You know, you are a genius, yes you are!
So obvious a design fault, leading to hard to detect intermittent errors, leading to lot of technical superstition, yet none undertook the task to make it a standard requirement to ensure that all system components let the system know their power requirements and that power supply let the system know its power capacity and that system can power-down each component separately as needed... I mean, it was in depicted in Sci-Fi for decades ("power from shields to cannons" and v-v)! Besides, it is even more critical parameter then temperature (and elevated temperature is only a consequence of power expenditure) which is religiously monitored everywhere.
"Perhaps I would agree if it were only one cable, but it's not. It's often four or five cables. My desktop, for example, has two printers, a scanner, speakers and a monitor, plus the CPU, so that's six power cables and six data cables (including the network)"
So? Work smarter. I have a 17" Apple MacBook Pro on my desk and it has exactly ONE cable connected to it: the MagSafe power connector.
The mouse I use (when I use one) is Bluetooth. My printer and speakers are plugged into an AirPort Express across the room. A 500GB hard drive and the big HP color laser are plugged into an Extreme in the next room, which is where the DSL line comes in and besides, it's quieter that way. Backups to the HD, while slower, are scheduled and occur in the background, so who cares how fast they happen? The network is obviously wireless, and 802.11n due to the Extreme.
I have a USB-powered Canon scanner, and I plug it in when I need to scan something (rare).
The Apple AirPort Extreme and Express are great options, and work on Macs and PCs. I think Belkin also has a wireless USB hub for PCs.
In short, if you have too many wires, then get rid of them.
Any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so.
Looking at the design of the port, it appears to add four more pins exclusively for power. So why the "one voltage" limitation? Even if you reserve one pin for a redundant ground -- the USB data cable and power cable may be connected to two different circuits on the device end -- you should still have enough connection ability to run three voltages in addition to the 5V in the USB data cable.
+12V seems like a no-brainer since the world is overrun with devices designed to operate at 12V. -12V also seems useful, especially if a circuit can use both to get a 24V rail-to-rail effect. Current PC power supplies are not designed to drive a whole lot on the -12V line, but at least the foundation is there.
The question would be what the best third choice would be. Would it cause interference issues to run, say, 90VAC at 400 Hz down the line? Devices that currently use inverters (such as scanners) would be able to drop them, while devices with high voltage demands would be able to use postage-stamp-size circuits to generate an arbitrary AC voltage. Power supplies already use intermediate stages on the way to the final +12, -12, +5, -5, +3.3 array we all know and love, maybe they can just be tapped directly at the intermediate stage.
I can understand the concerns about providing relatively high voltage AC over an easily accessible connector, but if it's properly designed it would be no more dangerous than wall outlets -- and there is generally one of those close to every stationary computer. Obviously laptops running on battery power would be ill-equipped to provide 90VAC, but mostly due to the high draw that would go along with it. When plugged in, their power bricks should be up to the task.
Whatever options are chosen, they should be be based on readily available commodity hardware. This keeps costs down, allowing the spec to attain wide acceptance. Asking current computer owners to spring $20 for a stand-alone power supply looks reasonable if it knocks $10 off the price of every device they attach to it. With just two devices -- printer and scanner for example -- they break even. If they can run other devices off it that do not use USB for data transfer (like monitors), hitting the two-device break-even point would be easily achieved. Then when they move on to the next computer, it will allow them to get rid of the extra box, but still use the peripherals they already have. Nobody would be compelled to buy the "retrofit kit" unless/until they also bought a device that requires it.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
I've got a 2.5" external drive case that uses two USB wires. One goes to a standard USB plug on the case, and the other goes to a connector that's just a power socket. Standard USB supports a given amount of power per connector, so this is getting around the limitation by doubling that. (Obviously you need a powered USB hub or direct connection from a computer, not a non-powered hub, and calling the new version "Powered USB" seems like an unfortunate naming collision.)
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
There are some other reasons why USB was adopted so widely. First off, it was hotplug. All the other ports like PS/2, Serial and Paralell required you to restart your computer if you wanted to change what was plugged in. USB finally allowed you to change devices while the computer was on. Imagine iPods or thumb drives if USB was not hotplug!
The other advantage of USB was that the plug is simple. It's just a rectangle that goes in a rectangular hole. You can't put it in backwards. There are no screws to hold it in. It's very approachable. Unlike serial, paralell or game ports, which look like they belong in the back of the computer and not the front, USBs are safe to put on the front of just about anything. The design of the port itself invites people to use it, rather than scare them away.
These are the other reasons USB is awesome, and also yet more reasons why Powered USB will not work. Adding any sort of extra plug will just make USB scary again. The only way I see powered USB working is if you find a way to transmit that power with a connector that is identical to the existing USB port.
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