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Data Storage Intel Software Upgrades Linux

Intel Developers Demo USB 3.0 Throughput On Linux 231

Posted by timothy
from the future-sweetness dept.
Sarah Sharp writes "Intel's Open Source Technology Center is working on USB 3.0 support for Linux. USB 3.0 has wire speeds of 5Gbps and promises to be 10 times faster than USB 2.0. A recent video demo shows speeds that are 3.5 times faster than USB 2.0. The USB 3.0 drivers will be submitted to the mainline kernel when the eXtensible host controller interface (xHCI) specification reaches a 1.0 release."
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Intel Developers Demo USB 3.0 Throughput On Linux

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  • by alain94040 (785132) * on Saturday December 13, 2008 @04:41PM (#26105909) Homepage

    USB 2.0 gave us high-speed and full-speed. Some marketing department had to work really hard on the USB 3.0 specs, to come up with... super-speed.

    Now let's talk about the obvious problem: at 5 Gbit/s, it's faster than the Ethernet in my house (1 Gbit/s). Am I the only one who didn't really notice a 10X speed improvement when moving from 100 Mbit Ethernet to gigabit Ethernet? Conventional hard drives are just too slow.

    Maybe SSD + USB 3.0 would be really cool. Imagine a Flash based HD camera talking to a Flash based hard drive. Is 2009 the year of the Flash?

    Which brings me back to my original point: for the next generation USB, I propose the name flash-speed :-)

    PS: thanks to Intel for helping Linux stay on the leading edge. It looks like Linux may even support this before Windows, thanks to the Windows 7 schedule... I just wish Intel's pre-conditions on contributing to the xHCI specs didn't start with stuff like:

    Step 1. Print and execute the xHCI Contributor agreement. Note: The agreement must be executed by a corporate officer.

    --
    http://fairsoftware.net/ [fairsoftware.net]

    • Re: (Score:3, Interesting)

      by Swizec (978239)
      What I'm wondering with the SSD computer + USB3 + Flash camera combo is ... does the computer even have enough processing power to complete the transaction while letting the user multitask somewhat normally?

      Or would the whole thing somehow circumvent the need to tell the OS what's going on with the file system?
      • by Microlith (54737) on Saturday December 13, 2008 @05:00PM (#26106045)

        This is why Intel is pushing USB: it is entirely CPU dependent.

        You won't notice it when you're running with X * 2 logical cores. It'll be shuffled off to some low utilization core.

        • Wha? (Score:5, Informative)

          by Weaselmancer (533834) on Saturday December 13, 2008 @05:12PM (#26106119)

          Could you please explain that a bit?

          It's my understanding that high throughput drivers usually use DMA. [mjmwired.net]

          In my experience polled mode drivers are pretty rare. Especially in high throughput.

          • Re:Wha? (Score:4, Insightful)

            by Lost Engineer (459920) on Saturday December 13, 2008 @05:30PM (#26106233)

            USB 2.0 requires the host to control all communication on the bus, and in practice uses more CPU time than something like 1394. I don't know if they changed this in USB3 or not.

            • Re: (Score:2, Informative)

              by Anonymous Coward

              The fact that USB is a polling protocol is a very low level decision. The CPU does not need to regularly ask each device for data. The USB controller does that.

              • Re:Wha? (Score:5, Informative)

                by Hal_Porter (817932) on Saturday December 13, 2008 @05:57PM (#26106405)

                Yup the host sets up a structure in memory which lists all the USB endpoints. When a driver wants to do some IO it asks the host controller driver which adds a request into the structure with a pointer to a buffer. The host controller hardware reads the structure with busmaster DMA and generates the USB packets. When the device answers the host controller DMAs the data into the the driver's buffer interrupts the CPU. Then the host controller can pass the buffer back to the driver. Polling is done by leaving the request in the structure, it doesn't require any CPU activity. Intel like USB because they invented it, not as some sort of conspiracy to load your CPU.

                • Re:Wha? (Score:5, Interesting)

                  by lysergic.acid (845423) on Saturday December 13, 2008 @06:48PM (#26106759) Homepage

                  so why do FireWire 400 readers still consistently beat out USB 2 [scribd.com]:

                  While USB 2.0's theoretical 480Mbp/s (60MBp/s) throughput should be sufficient for UDMA 4 CompactFlash, realthroughput is significantly less. Top hard drive manufacturers typically cite USB 2.0's best speed at 33MB/s, or abouthalf the speed of UDMA 4 CompactFlash, or 25% of UDMA 6 CompactFlash. There are myriad reasons for USB 2.0's'real world' speeds including: CPU overhead from its master/slave arrangement, NRZI encoding, and inexpensivechipset implementations. The USB 2.0 UDMA reader used in the benchmarks above uses one of the latest USBchipsets from Genesys Logic. While a new generation of that chipset should soon be available, we don't foresee itproviding throughput close to half of that of FireWire.

                  heck, those benchmarks show that even using FireWire 400 to read a PIO CompactFlash card still beats USB 2.0 UDMA reading a UDMA-enabled CompactFlash card.

                  • Re:Wha? (Score:5, Informative)

                    by raynet (51803) on Saturday December 13, 2008 @07:10PM (#26106927) Homepage

                    Taken from wikipedia: "Although high-speed USB 2.0 nominally runs at a higher signaling rate (480 Mbit/s) than FireWire 400, typical USB PC-hosts rarely exceed sustained transfers of 280 Mbit/s, with 240 Mbit/s being more typical. This is likely due to USB's reliance on the host-processor to manage low-level USB protocol, whereas FireWire delegates the same tasks to the interface hardware. For example, the FireWire host interface supports memory-mapped devices, which allows high-level protocols to run without loading the host CPU with interrupts and buffer-copy operations."

                    • Answers my question perfectly - thank you.

                    • Re:Wha? (Score:5, Informative)

                      by mabhatter654 (561290) on Saturday December 13, 2008 @08:12PM (#26107387)

                      This is why you can't have USB-to-USB devices like you have Firewire-to-Firewire devices. It's why USB is very bad for time-sensitive data like music and video, because you're always waiting for the host controller to do something on the CPU, which might be busy.. have you ever seen DMA to memory ever work properly on consumer grade hardware anyway?

                      It's not so much a "scam" as it is designing to the market. Firewire devices have a non-trivial price premium because of the device-to-device controller... but that's why they can do things like daisy-chain or direct connect between computers with no special cables. On the other hand USB allows endpoint devices to be made very cheaply.. they have near-zero intelligence if you want. The USB host can be as "thick" or "thin" as the OEM wants... they can put all the host chip control in software drivers to keep chip cost down. They can also put all the control codes for devices in software... remember "wINKjets" that went obsolete with each new Windows version... they have almost no internal software at all.

                    • Re:Wha? (Score:5, Interesting)

                      by lysergic.acid (845423) on Saturday December 13, 2008 @10:07PM (#26108087) Homepage

                      good point. and to be honest, most people don't need FireWire 800/1600 just to transfer a few documents or spreadsheets--or even photos & mp3s--to their computer. the few seconds saved doesn't justify the added cost of FireWire over USB. nor do they need to use a high-speed data bus for their mouse, keyboard, webcam, printer, scanner, or what have you. so it makes sense that USB is more prevalent than FireWire.

                      however, FireWire is still extremely useful (and crucial) to certain professionals who regularly work with large files or have to move around large amounts of data, like hi-res/raw images, lossless audio, hi-def video, etc. that's why FireWire is still pretty standard in high-end music & video production equipment. so the idea that FireWire is dead (or can simply be replaced with USB 2.0/3.0) is just poorly informed.

                      even the military still uses FireWire for things like the the F-35's vehicle systems network [itwire.com]:

                      1394b is playing a pivotal role in the F-35 Lightning II program, providing guaranteed quality of service with predictable latencies in real-time control applications. More than 70 1394 devices are delivering information about mission details, communication systems, weapon systems, engine controls, and flight controls.

                      the IEEE-1394B data bus is similarly employed in the F-22 Raptor [aviationspectator.com] for which it was developed. and NASA also uses it [findarticles.com] to monitor debris during launches amongst other mission-critical applications [daptechnology.com].

                    • Re:Wha? (Score:4, Informative)

                      by afidel (530433) on Saturday December 13, 2008 @11:26PM (#26108435)
                      have you ever seen DMA to memory ever work properly on consumer grade hardware anyway?
                      Yeah, every day. PIO mode HDD's suck terribly, DMA is necessary to achieve decent performance.
                    • Re: (Score:3, Insightful)

                      by dgatwood (11270)

                      What I don't get is why anybody cares about USB 3.0. For disks, its performance will suck compared with eSATA for lots of reasons (lack of true DMA, slower bus, more protocol overhead etc.). For any serious audio/video tasks, FireWire works a lot better and is already generally fast enough for 99.9% of users (and PCIe is a great alternative for that .1%). For all other devices, USB 2.0 is fast enough (and for that matter, USB 1.1 was usually fast enough). What's the intended market for this technology?

                    • Re: (Score:3, Informative)

                      by eh2o (471262)

                      That isn't correct--USB also has an isochronous transport mode that guarantees timely access and bandwidth to a streaming device.

                      Also there is USB On-The-Go (OTG) which is for ad-hoc point-to-point communication between devices without a host controller. That was released as a 2.0 spec supplemental and is commonly found in ... printers that you can plug your camera into, for example.

                • Re:Wha? (Score:5, Insightful)

                  by yoyhed (651244) on Saturday December 13, 2008 @07:46PM (#26107211)

                  Yup the host sets up a structure in memory which lists all the USB endpoints. When a driver wants to do some IO it asks the host controller driver which adds a request into the structure with a pointer to a buffer. The host controller hardware reads the structure with busmaster DMA and generates the USB packets. When the device answers the host controller DMAs the data into the the driver's buffer interrupts the CPU. Then the host controller can pass the buffer back to the driver. Polling is done by leaving the request in the structure, it doesn't require any CPU activity. Intel like USB because they invented it, not as some sort of conspiracy to load your CPU.

                  I know it's off-topic, but I thought I'd point out why I love Slashdot by comparing it to Digg. If this story were on Digg, the comments would be something like "I BET THIS BE ON NEXT MACBOOK PRO LOL". Here, we get something like your comment in the first thread. <3 /.

                • by billcopc (196330)

                  That's all fine in theory, except practically every USB chipset in use today does not take advantage of that architecture, i.e. they offload the difficult stuff to the CPU, because software is cheaper than hardware.

                • by Hatta (162192)

                  Someone could make a pile of cash selling USB cards with hardware accelerators.

          • by Gazzonyx (982402) on Saturday December 13, 2008 @06:27PM (#26106639)
            Well, I get high throughput with my NIC drivers that poll (I can't remember the kernel compile option for this ATM), but this is at the cost of a higher latency. The trade off is that I've got 5 NICs on this box and it turns out that without polling I get close to having an interrupt storm and spend all my time switching context to execute the drivers bottom half of the interrupt. With polling, the interrupt gets masked and I don't have to worry about servicing every interrupt coming down the line. My latency is higher, but I get more throughput for every time I service the bus as it has more packets to process. This also means I'm trading off space for time (I need larger ring buffers to queue packets) such that I have less memory for the system, but processes get more time on the processor between interrupts.

            While not having to do with USB, the driver architect and concepts are likely very much the same.
    • Re: (Score:2, Funny)

      by Anonymous Coward

      Look, we both know that there will be a "USB ludicrous speed". Marketing has no say in it.

      • Re: (Score:2, Funny)

        by Anonymous Coward

        We've gone plaid.

    • Re: (Score:3, Informative)

      by Microlith (54737)

      Imagine a Flash based HD camera talking to a Flash based hard drive.

      Maybe if said HD camera has a USB host controller, like that USB-2-GO stuff.

      Otherwise, I suspect USB 3.0 is as braindead as USB 1.0 and will still require a computer to do all the actual work.

      • Like Firewire has been able to do since day 1?

        • Re: (Score:2, Informative)

          by billcopc (196330)

          Yes, but the difference is a USB device or controller costs about 2 yen, while a Firewire endpoint costs about $20, half of that in licensing alone!

          Firewire is by far a superior interlink in terms of performance, but it is overpriced (you can thank Steve Jobs for that one).

          • by 0100010001010011 (652467) on Saturday December 13, 2008 @09:00PM (#26107705)

            The agreement essentially brings patents held by these companies into a single portfolio that can then be licensed by manufacturers for a single fee. That fee is US$.25 per system that includes FireWire ports, regardless of the number of patents used or the number of FireWire ports implemented. This is a dramatic decrease from the US$1 per port per device (see "Apple To Charge 'Per-Port' Licensing On FireWire") that Apple originally announced it would charge for its own patents.

            $10 is not in licensing fees.

          • 100% Bull Shiat. Google for the Firewire licensing fees.

          • by tonywong (96839)

            Why is the parent post modded informative when the reply shows that this is obviously wrong?

            Even the parent's response to the reply is modded up when it is wrong again.

    • Re: (Score:3, Interesting)

      by Mad Merlin (837387)

      The thing is that USB is bursty, in practice you'll probably still get much better speed out of Gigabit ethernet than you will with USB 3.0.

      As for Gigabit ethernet, it's a massive upgrade from 100 megabit ethernet, at least in my usage. It only takes 2 modern drives in RAID 0 to saturate Gigabit ethernet, or just 1 fast SSD.

      • 'bursty' ... is that sort of like 'minty'? ;)

        in practice you'll probably still get much better speed out of Gigabit ethernet than you will with USB 3.0.

        Seriously though, [citation needed].

        • by Mad Merlin (837387) on Saturday December 13, 2008 @05:31PM (#26106237) Homepage

          'bursty' ... is that sort of like 'minty'? ;)

          No, it's that max speeds for USB 2.0 refer to the max burst speeds, not the maximum sustainable speed. A single 7200 RPM drive attached via USB 2.0 will be substantially slower than if you attached it via SATA or IDE, even though 60 MB/s (= 480 Mbit/s) should be enough for most drives.

          • by More_Cowbell (957742) * on Saturday December 13, 2008 @07:05PM (#26106871) Journal
            I appreciate the answer, but you replied to the bit where I was trying (poorly) for humor. I know what burst speed vs sustainable speed is all about. What I wanted you to explain is what makes you think a medium that has a burst speed of 4.8 Gbit/s will not be able to sustain > 1 Gbit/s (like your ethernet). I have read a bit, and not seen any info either way...
            • What I wanted you to explain is what makes you think a medium that has a burst speed of 4.8 Gbit/s will not be able to sustain > 1 Gbit/s (like your ethernet). I have read a bit, and not seen any info either way...

              Pessimism based on USB's poor performance (as far as high speed devices go, anyways) in the past and general pessimism. I actually consistently see sustained speeds of ~115 MB/s over Gigabit ethernet, which is extremely close to the theoretical speed (minus TCP overhead), but I've never seen anything close to 60 MB/s over USB 2.0. Only time will tell for sure though.

    • by John Allsup (987) <<moc.liamg> <ta> <euqsilahc.s>> on Saturday December 13, 2008 @05:11PM (#26106111) Homepage Journal

      I guess for hard drives, the question is how close to eSATA it gets.
      Also, does USB3 still have the CPU overhead and latency of earlier USB compared to FW?

      • by afidel (530433)
        Hmm, a crappy host based implementation at 5Gbps or a storage targeted, low everhead one at 3Gbps (possibly going to 6Gbps if the next gen spec gets extended to eSATA), I know which one I will use =)
        • Re: (Score:3, Informative)

          by saharabeara (1430929)

          Hmm, a crappy host based implementation at 5Gbps or a storage targeted, low everhead one at 3Gbps (possibly going to 6Gbps if the next gen spec gets extended to eSATA), I know which one I will use =)

          Actually, USB 3.0 was targeted for mass storage devices. They added the concept of Bulk Streams to support "out-of-order data transfers required for mass storage device command queuing." (USB 3.0 spec, section 4.4.6.4) Basically, the host can queue up to 65K SCSI commands, and the device can choose which command it wants to service first.

          The host doesn't have to poll the device to see when commands are done because they added device notifications to USB 3.0. So the host fires off 65K of SCSI requests and

    • PS: thanks to Intel for helping Linux stay on the leading edge. It looks like Linux may even support this before Windows, thanks to the Windows 7 schedule... I just wish Intel's pre-conditions on contributing to the xHCI specs didn't start with stuff like:

      Honestly, Intel didn't have much choice, the NT kernel can't exactly be obtained, modified and distributed for free, OS X is too hardware-oriented, and there isn't really anything else (minus BSD and other *Nix variants)

      • Re: (Score:2, Interesting)

        by Hal_Porter (817932)

        Honestly, Intel didn't have much choice, the NT kernel can't exactly be obtained, modified and distributed for free

        At the moment Windows supports three host controller drivers. OHCI and UHCI for USB 1.0 and EHCI for USB 2.0. There's nothing special about host controller drivers, anyone can write one. If they wanted they could write a host controller driver for xHCI and then Windows would support USB 3.0.

        • by hairyfeet (841228)

          Not to mention someone with the money and industry clout of Intel would have no problem calling up MSFT and saying "We have this great new gadget we are about to release but we will require your source to complete it." and faster than you can say NDA I have no doubt that Intel would be looking at the Win7 source code, along with the source to anything else they wanted.

          I personally am just glad this is from Intel and not MSFT, otherwise it could have ended up a Win7 only feature just like DX10 for Vista.

      • by Valdrax (32670)

        Honestly, Intel didn't have much choice, the NT kernel can't exactly be obtained, modified and distributed for free ...

        What does that have to do with the price of tea in China?

        You think nobody writes userspace drivers in the Windows world?

    • Re: (Score:3, Funny)

      Is 2009 the year of the Flash?

      Indeed. On the desktop!!

    • by metalhed77 (250273) <<andrewvc> <at> <gmail.com>> on Saturday December 13, 2008 @05:39PM (#26106287) Homepage

      That USED to be true. It's not the hard drive, all the layers that get put in between when you access a disk over the network. Modern hard drives can easily do 60MB/s sustained.

      For instance, I have a couple raid6 arrays which clock in at about 250 MB/s and 150MB/s natively. If I hook that machine up directly to another machine's ethernet port I only get about 30MB/s sharing the device w/ iSCSI. SMB and NFS yield similar results. This is true even though I can get over 900Mbps using iperf.

      Sharing disks over gig-e sucks when you actually need throughput. It's great for when you just need to expand a SAN and speed is secondary. I've heard that bonding two Gig-e cards doesn't realize much of an improvement FWIW, so I assume latency is part of the reason it's slower.

      • by Mr Z (6791) on Saturday December 13, 2008 @09:56PM (#26108005) Homepage Journal

        Protocol latency is a big deal. If you have a large per-transaction overhead, then the overall throughput of a given medium will be very sensitive to the number of transactions it creates on the media, as opposed to the total number of bytes it needs to move.

        That's part of the reason the HTTP sprouted request pipelining [mozilla.org], since the round-trip-time between the endpoints of the connection figured largely in the startup latency of each connection.

        It sounds like the typical PC implementation of USB relies heavily on the CPU to handle all but the lowest levels of the protocol. (I'm relying on hearsay here.) If this is indeed the case, then it'll be hard for USB to reach the max sustained speeds for storage devices, unless there's a mechanism for requesting large blocks of data (or large numbers of small blocks) in a single transaction.

        For us old-school types, it's similar to the reason XMODEM didn't get much faster with faster modems over a certain speed. XMODEM didn't pipeline anything. It'd send a block, and then wait for an ACK. Since the latency of fancier modems was higher than the simple FSK 300 baud modems, the handshake turnaround time of the ACK swamped the gains made while sending the blocks. (Also, the tiny block size didn't help.) Thus, pipelined protocols like ZMODEM and large-block non-pipelined protocols (XMODEM-1K) came about to address this.

    • Re: (Score:3, Informative)

      by gad_zuki! (70830)

      >Am I the only one who didn't really notice a 10X speed improvement when moving from 100 Mbit Ethernet to gigabit Ethernet?

      Well, youre probably not getting 10x. Depending on a slew of factors (your switch, cable length, etc) youre getting anywhere between 100 to 800 mbps. Have you tried any speed tests? With gigabit I can copy to my nas at 25 megabytes per second. At 100 I was getting under 12. So that's twice the speed for me, which is most likely limited by the CPU on my nas and not ethernet.

      >Conve

      • by gbjbaanb (229885)

        With gigabit I can copy to my nas at 25 megabytes per second. At 100 I was getting under 12. So that's twice the speed for me, which is most likely limited by the CPU on my nas and not ethernet.

        When the networks stops being the bottleneck, you usually find it shifts somewhere else - I think now your bottleneck is the HDDs write performance. My NAS copies at 25MBps but before I reformatted it from its default RAID5 on its useless raid card, I was getting 6MBps (its now JBOD with software RAID), the CPU isn't

    • Linux actually has much better USB2 support than Windows... as in much better throughput. Each device gets to use more bandwidth.

    • Re: (Score:3, Informative)

      by LoRdTAW (99712)

      Gigabit Ethernet is a vast improvement over 100Mbit. Two windows boxes with fast SATA drives I see no less than 20 megabytes/second transfer speeds on a Vista64 XP64. Top speeds exceed 30 MB/sec (~300+Mbps)! My home server runs Linux but for some reason SAMBA is dog slow no matter how much I tweak the damn conf file. 10-12MB/sec tops for Linux Windows (without tweaks it was 3-4MB/sec!).

      I have a four disk 1.5TB raid 5 array using SATA disks on a pciX controller and mdadm. Copying from the array to an **old

    • by sjames (1099)

      For a single device, you probably won't really notice 5Gbps. However, let's say you have 3 USB drives that can sustain 1Gbps each. If you hang them off of a decent USB hub, you'll be glad the bus can do 5Gbps.

    • Re: (Score:2, Funny)

      by averagegeek (1431079)

      PS: thanks to Intel for helping Linux stay on the leading edge. It looks like Linux may even support this before Windows, thanks to the Windows 7 schedule

      The real question is...will Tux get fat with all the new code?

    • by Belial6 (794905)
      It might not matter if your house has one hard drive in it. In my house, we have over a dozen drives. 5 Gbit/s might outrun a single attached drive, but USB was supposed to handle 256 devices attached at once. The only reason that we need 6 USB controllers on a PC is because it is just too slow. USB 2.0 was a bottle neck. I suspect that it still will be, but if it isn't the bottle neck, then don't complain about USB 3.0, complain about whatever has become the new bottle neck.
    • "Step 1. Print and execute the xHCI Contributor agreement. Note: The agreement must be executed by a corporate officer."

      Those corporate officers have all the fun, executing this, executing that.

  • Replace HDMI?
    HD-resolution cameras, etc?
    The next, even more expensive, version of the USRP?

  • CPU usage (Score:2, Redundant)

    by PhrostyMcByte (589271)
    Like any good slashdotter, I'm not reading the article until after I post. Is 3.0 still going to be heavy on the CPU? Really, the best thing they could do is take the good stuff from firewire and slap a USB logo on it. All the cheap stuff can continue to use 2.0, while the bandwidth intensive stuff in 3.0 can have their own controllers.
  • yeah yeah, i read the comments about gigabit ethernet being faster, thats not the point, usb 3 is still better than usb 2, enjoy the weekend...
  • Motherboards (Score:3, Interesting)

    by Enderandrew (866215) <.enderandrew. .at. .gmail.com.> on Saturday December 13, 2008 @05:24PM (#26106189) Homepage Journal

    When can I buy my first motherboard that is USB 3.0 compliant? I want to build a rig in the spring. I'd consider holding off until the summer to get USB 3 so it is more future proof, but I won't wait another year.

    • by eebra82 (907996)
      The question is, what do you really need it for? You would need peripherals with USB3 to benefit from it and most USB items don't even need such raw speed. Keyboards, mice, printers and many other things do just fine.

      Don't wait for USB3. When you really need USB3, just get a PCI card with two or three ports and voila. These things hardly cost more than 20 to 30 bucks.
      • Video capture is the first thing that springs to mind, as well as external HDDs, flash storage, etc. Right now, copying gigs of data to external storage is slow with USB 2. Also, video capture is problematic. If the data isn't moving fast enough, I drop frames of video.

        • Video capture is the first thing that springs to mind, as well as external HDDs, flash storage, etc. Right now, copying gigs of data to external storage is slow with USB 2. Also, video capture is problematic. If the data isn't moving fast enough, I drop frames of video.

          Firewire for the video capture and eSATA for the external hard drives will solve both problems. Even eSATA flash drives are showing up on the market now.

    • Re: (Score:3, Insightful)

      by kklein (900361)

      Please don't say "rig."

  • latency badness (Score:5, Interesting)

    by r00t (33219) on Saturday December 13, 2008 @06:07PM (#26106477) Journal

    USB suffers from 1 ms time quantization and thus latency. I see nothing about fixing this.

    Example badness:

    When running MIDI over USB, timing is forced onto 1 ms slots. Normally when playing a chord, the keys don't all hit at exactly the same moment. You can't really tell, except that this makes the music sound natural. With the 1 ms problem, the keys happen at exactly the same moment (bad) or spread out into two separate events (worse).

    • Is firewire a good alternative without that problem?
      • Re: (Score:3, Informative)

        by setagllib (753300)

        Sampling and encoding the events before they hit the limited USB connection is. That requires extra equipment, however.

  • Compared to USB 1... (Score:5, Interesting)

    by MonoSynth (323007) on Saturday December 13, 2008 @06:07PM (#26106479) Homepage

    This shows where Linux is nowadays. It took literally years before USB1 was even supported and now Intel uses Linux to prove USB3's performance!

  • by IHC Navistar (967161) on Saturday December 13, 2008 @06:10PM (#26106511)

    USB 1.1: Low-Speed and Full-Speed

    USB 2.0: High-Speed

    USB 3.0: Super-Speed

    USB 4.0: Mega-Speed

    USB 5.0: Ultra-Speed

    USB 6.0: ???-Speed

  • by Anonymous Coward on Saturday December 13, 2008 @06:11PM (#26106517)

    Whenever a story about USB3 is written, the following caveats should be mandated by law if necessary:

    1. Speed claims are theoretical, and do not reflect real-world results by a long shot. Lots of overhead, CPU dependence, etc.

    USB2 promised 480Mbps and never delivered it. You get 250Mbps on a good day. Now we have marketing claims that USB3 will be "10x faster," yet a video demo shows it's 3.5x faster. That's 1.5Gbps, not 5Gbps.

    2. Firewire 3200 is approved and on the way. It will be faster than USB3, backward-compatible with FW800 (same cables and ports) and should begin appearing on Macs in January. Firewire isn't dead; Firewire 400 is being eased out in favour of faster versions.

    If FW 3200 performs like its predecessors, it should be (in real-world usage) routinely about 2x faster than USB3.

    Moral of the story: don't settle for mediocre.

  • Security (Score:3, Informative)

    by MSG (12810) on Saturday December 13, 2008 @07:04PM (#26106855)

    An awful lot of people are looking down their noses at USB 3 because it's not Firewire. Has everyone forgotten that Firewire grants devices DMA access to physical memory? Any physically connected device can be used to bypass the system's security. I'm grateful that USB isn't more like Firewire.

    • by pizzach (1011925)

      An awful lot of people are looking down their noses at USB 3 because it's not Firewire. Has everyone forgotten that Firewire grants devices DMA access to physical memory? Any physically connected device can be used to bypass the system's security. I'm grateful that USB isn't more like Firewire.

      The people on slashdot maybe. Lay people still think USB2 is faster than the original Firewire. Even if you are not going to have to deal with the direct DMA access through Firewire, eSATA will be appearing soon on cheap computers near you to replace Firewire 1...

  • by wikinerd (809585) on Saturday December 13, 2008 @08:27PM (#26107473) Journal
    Wake me up when Firewire over UTP [wikipedia.org] gets popular. THAT would be interesting.
  • by billcopc (196330) <vrillco@yahoo.com> on Saturday December 13, 2008 @08:51PM (#26107639) Homepage

    Why are they wasting everyone's time with USB 3.0, when the rest of the universe is shifting toward Ethernet as a common interconnect ? Note I didn't say IP, just Ethernet - good old CAT-5.

    Frig, if the audio folks have already started that transition, then what the hell is Intel doing ? The audio industry is probably the most retarded in the world (according to my failed expectations), and even they see that Ethernet is a cost-effective and braindead simple replacement for all these proprietary cables we've had to contend with over the years.

  • by mmcuh (1088773) on Sunday December 14, 2008 @02:55AM (#26109225)
    One thing that is at least as important for free software systems as speed increases is class compliance. Take audio and MIDI devices for example. Almost all USB 1.0 audio and MIDI devices are class compliant, and thus work reasonably well with the standard kernel module snd-usb-audio. But with USB 2.0 that changed for some reason - now many more devices require special drivers that often do not exist for Linux. It would be nice if Intel and friends could somehow push for more class compliant USB devices.
    • Re: (Score:3, Informative)

      by eh2o (471262)

      USB hasn't changed the approach towards class compliance, and they continue to improve those related specifications. If you want to point fingers, look at the hardware and software vendors. FTDI, for example, makes a nearly ubiquitous USB-serial chip that is not class compliance in spite of the fact that every major OS supports the serial device class.

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