USB 3 in 2008, 10 Times as Fast

psychicsword writes "Intel and others plan to release a new version of the ubiquitous Universal Serial Bus technology in the first half of 2008, a revamp the chipmaker said will make data transfer rates more than 10 times as fast by adding fiber-optic links alongside the traditional copper wires." "The current USB 2.0 version has a top data-transfer rate of 480 megabits per second, so a tenfold increase would be 4.8 gigabits per second." This should make USB hard drives easier and faster to use."

Comments

Re:I'm more concerned with latency.

[Laebshade]

I can't find the exact article, but you should read this one about the effective USB 2.0 speed. It states that the effective maximum speed is only about 40MB/sec, and that 60MB/sec can't be achieved due to overhead/software limitations; not sure if this is true now.

Re:I'm more concerned with latency.

[schwinn8]

Exactly... Firewire400 works well for video streaming from a DV cam because it has very little overhead. Even though USB2 supposedly does 480Mbps, it can't do DV because there's too much overhead. Bottom line is, unless USB3 gets rid of the CPU dependency and overhead issues, I won't like it. Sure, with a "ten times" the performance, this won't hinder DV, but that doesn't make it good. I hope they make it systemically-efficient, instead of just ramping clock rates to reach these speeds.

Re:Yeah, but..

[ggeens]

When I was working on my Master's thesis, I had to splice optical fiber a few times. Believe me, it's not easy.

Glass fiber is very flexible. You can bend it in any way you want, it won't break. You can cut it, but that takes considerable force. If you break the fiber, you'll break the copper wires as well.

Personally, I think the weakest point in such a cable will be the connectors. Getting the light from one fiber to another requires careful alignment. Any deviation might causes loss of signal. Getting dirt into the connector is probably fatal.

Honest Question

[martyb]

I've got a question that has been nagging at me for quite a while and was hoping someone here could phrase an answer in terms a mere mortal could understand.

Why are there so many serial specifications?

We've got, off the top of my head, SCSI, USB, Ethernet, FireWire, and SATA to name a few. I do understand there are different protocols (all the way up from the physical to the application layers). Different applications of these technologies permit some optimizations that might not be applicable in other situations. But, at some point, the underlying technology is fast enough

Still, I can't help but think there should be some common denominator that ALL these communications standards can agree on, and through economies of scale, become universal standard(s). It just seems like people keep re-inventing the wheel with an eye toward THEIR favorite.

I thought we were getting close when they released gigabit Ethernet over UTP (unshielded twisted pair).

• can handle distances up to 100 meters
• fast data rate (1000 Mbps)
• supports lower data rates (100/10 Mbps)
• development is underway for 10Gbps, too.

So, for the sake of argument, why not have all of our serial devices just support gigabit Ethernet? Sure, you'd need a hub or switch in your PC to talk to all of the devices, but you already need something similar for the other protocols (USB hub, SCSI controller, etc.). It's a well-known technology with many implementations and is widely available. I'd willingly pay a few more bucks for each device if I could ditch all of these incompatible formats and just standardize on one SET of ports and cables for hooking things to (and within) my PC. And in those cases where a different connector is desired (e.g. for small form-factor devices like a digital camera), let me just get an adapter cable/plug that I can plug into my Ethernet port.

Is there any good, technical reason that is keeping us from having truly UNIVERSAL serial communications?

Re:Honest Question

[mlBrianR]

I think the main problem is repeated insertion/removal vs. semi-permanent installation.

USB connectors are designed to be inserted and removed over and over. They're held in by pressure against the connector, so they can be removed without having to push a tab or twist the connector to remove it.

UTP cables are designed to be plugged in, and then generally left alone. The UTP cable in my computer bag is in terrible shape.. the RJ45 connector is coming loose, the plastic retaining tab is broken off (so the cable often pops out of the jack on its own), etc.

I have USB devices which I've removed and inserted hundreds of times, and the connectors still work reliably.

Re:Honest Question

[gillbates]

Is there any good, technical reason that is keeping us from having truly UNIVERSAL serial communications?

Yes.

Let me explain:

• USB, per standard (host side), must be able to source at least 500 mA. Even though there is a PoE (Power over Ethernet) standard, most choose not to implement it by default. Hence, ethernet can't power devices like flash drives and hard drives.
• USB uses four wires, ethernet twice as many. USB is a synchronous bus, meaning that there are (theoretically, at least) no collisions. A properly operating USB device will not stomp on someone else's data packet. Thus, for the given bitrate, a higher portion of the bandwidth is available to applications. Unlike ethernet, adding devices to the same physical connection will not degrade the overall bandwidth of the network. In practice, I've found 100 Mbit ethernet devices operating with a maximum throughput of about 35-40 Mbits/second because of collisions. And this was with *two* devices! To get a better throughput requires using routers (which minimize or eliminate collisions).
• RS232 is a pretty universal serial communication standard. However, it is also slow.
• There are tradeoffs between maximum cable length and the speed of the bus.
• There are tradeoffs between the number of signal lines and the cost of the device.
• There are tradeoffs between bitrate and the device cost.

So, the reason why we don't have a universal serial standard is because the different interfaces were designed with different goals in mind.

Re:I'm more concerned with latency.

[Barny]

Mod parent up, hammer meets nail in their post :)

Bonus points if you hook a 108mb/s wireless lan adapter via USB and throw some large data files over it, watch your data speeds closely, and monitor system performance even closer.

Firewire (1394, ilink, DV port, whatever) really was the shit, not only fast, low overheads AND its a peer-2-peer setup, in a pinch you could daisy chain PCs with it for an impromptu 400mb/s lan.

Why didn't they just hang USB out to dry and get power into the eSATA spec and use that? At least then no extra chips would be needed on a mobo, external HDD would hookup with no loss in performance and we might finally see thumb drives that work natively with ANY os as... drives.