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."

Comments

USB needs to add more firewire like stuff

[Joe The Dragon]

like offloading work from the cpu as the older and slow fire wire 400 bus is faster then the usb 2 bus and it can be used to link 2 systems together with out a special cable.

Cable Spaghetti

[Anonymous Coward]

You know what we really need?
 
Wireless power supplies.

I sincerely hope powered USB fails

[Thagg]

I don't feel that computer designers should really have to think about some peripheral device sucking 50 watts out of a connection on the motherboard. If you want power, get a cord. If you want portable power, bring a battery. Just having one fewer cable on a desk is not a problem worth solving this way.

Laptops, for instance, are designed around very limited power budgets. If you plug a 1000 watt USB hair dryer into it, how long are the batteries going to last?

A solution I would be in favor of is building lower power peripherals. Building 500 GB flash hard-drive replacements than run on half-a-watt should be possible in a couple of years. Building very low power OLED displays should be possible. Building low-power devices is something that is a win in every possible way, and should be encouraged -- the USB power limitation is a great way to stimulate this!

That said, I'm really sorry I passed up the USB-powered heated typing gloves I saw in Shinjuku last fall...

Thad Beier

Re:I sincerely hope powered USB fails

[swillden]

I don't feel that computer designers should really have to think about some peripheral device sucking 50 watts out of a connection on the motherboard.

Why not? Sure it's another factor in motherboard design, but as long as the USB peripheral and the controller can negotiate the power demands, then it's easy enough to make sure it's not going to burn anything out. If a device would draw more power than the mobo would supply, the controller simply wouldn't power it. That would make USB-deliverable power another feature by which to compare mobos.

Just having one fewer cable on a desk is not a problem worth solving this way.

I disagree. 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). Worse, the six power cables require two power strips (because the wall warts cover more than one outlet on a typical power strip), so there are an additional two cables, for a total of 14 cables under my desk, for that one computer. Powered USB, if done right, could conceivably eliminate both power strips and all but one of the power cables, so instead of 14 cables, I'd have seven. Even better, the routing of the seven would be cleaner, since all of the peripheral cables connect to the computer and the compute is the only one that connects to the wall. That's well worth doing.

Laptops, for instance, are designed around very limited power budgets. If you plug a 1000 watt USB hair dryer into it, how long are the batteries going to last?

Not long, of course, but if I want to do that, and if the laptop can deliver the juice (unlikely in your example, but we could construct another that was more feasible), why shouldn't I be able to? They're my batteries and the power in them is mine to spend as I please.

A solution I would be in favor of is building lower power peripherals. Building 500 GB flash hard-drive replacements than run on half-a-watt should be possible in a couple of years. Building very low power OLED displays should be possible. Building low-power devices is something that is a win in every possible way, and should be encouraged -- the USB power limitation is a great way to stimulate this!

Given the increasing move to portables and the apparently-insurmountable limitations of batteries, I think that problem takes care of itself. Low-power USB-powered devices would have an inherent mobility advantage that would drive their sales over hungrier devices. They'd also be cooler and quieter, which also tends to please buyers. There's no reason to impose an artificial barrier which makes classes of devices that can't quite reach the 0.5A mark completely infeasible.

yes, but no

[nanosquid]

Powered USB sounds like a mess. But I wouldn't count those people out. Keep in mind that USB 1.0 looked like it was never going to make it compared to FireWire.

Furthermore, with wireless USB, the whole thing is up in the air: wireless data with wired power may well be a better way to go overall, and Powered USB may simply not be aimed at the consumer at all.

Incidentally, the set of FireWire-powered devices seems similar to the set of USB-powered devices, meaning that the higher power available from FireWire doesn't seem to be sufficient to enable a whole lot of new applications.

Re:yes, but no

[nanosquid]

What does it give you that Bluetooth or Wi-fi doesn't?

Foremost, USB driver compatibility. That alone would be sufficient.

Also, higher data rate, shorter range (yes, that's a plus), easier configuration, lower cost, easier management.

Re:Wireless

[swillden]

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.

Right, so you get rid of some cables at the expense of accepting a small, low-resolution screen with limited contrast and small, slow data storage. Not a good tradeoff for me, at least (as compared to the 23" 1920x1440 CRT and striped 320 GiB 3Gbps SATA drives on my desktop).

If a laptop can accomodate your computing needs and fits into your budget, then certainly it's a good way to eliminate (some) cables.

My printer and speakers are plugged into an AirPort Express across the room.

Which means you haven't gotten rid of any of those power cables (or the power strip, most likely), you've just moved them away from your desk. Not a bad thing, certainly, but not as good as eliminating them. Now imagine how clean it would be if the AirPort Express supported powered USB devices, and your external drive and printer ran from that.

Also, I should point out that my LAN is GigE for a reason. I move a lot of big files around and even 100BaseT is annoyingly slow (I can't saturate the GigE, but I get transfer rates about 3x as fast as 100BaseT could handle). I have an 802.11g WiFi network, but even my laptop is plugged into the GigE when I'm at my desk, because WiFi is just too slow when you need to move data.

I have a USB-powered Canon scanner, and I plug it in when I need to scan something (rare).

So there are two more cables on your desk, though one of them isn't typically attached to your computer. Again, powered USB would eliminate one of them.

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.

Certainly, if they work for you and if you don't mind paying for them. Also, I don't think they work for Linux, except for the music playing option (I'd like to be wrong here!). They don't, however, really remove the need for cables so much as allow you to spread the cables around a little more. That's not bad, but it's not as good as eliminating them.

Re:Why powered USB will fail

[CityZen]

Actually, DC to DC voltage conversion is cheap and small (and efficient) these days, thanks to IC switching PSU controllers. Only big part left is just the coil (which is still fairly small).

With regard to the article, it looks like the new Powered USB spec is a designed-by-committee mess, trying to do too many different things. I think they should just put a stake in ground for a single power output spec (and single plug) that supports most applications and not worry about the rest (high powered items). This will provide an incentive to invent lower-power designs for those currently high-powered gadgets. How many people need a USB-powered hairdryer anyway?

Re:I agree

[jelle]

USB always makes me struggle which way to put the connector in. Firewire is a little better, but still, you'd think that the people who make connectors would be able to come up with either a connector that makes it obvious which way it goes in, or one where it doesn't matter how it goes in.

We're still in the 'connector stone-age' if you ask me...