The Next Step, Hi-Speed USB 2.0 — THG.RU

Introduction

The article first appeared in Tom’s Hard News Email Newsletter

The USB 2.0 standard still remains a mystery to many users, but this is not for lack of trying to get the message across as to what, exactly, USB 2.0 is. USB 2.0 is the next step in building a more forward-thinking version of the USB technology. When the first version of USB was released to the public, high-speed devices that need the kind of bandwidth that USB 2.0 provides were little more than a dream. At that time, most high bandwidth applications were left for IEEE-1394 (Fire Wire) and it looked like it would remain that way until the introduction of USB 2.0.

If you look at the back of your computer you will see a few different communication ports. You will see a parallel port (printer port), an RS-232 serial port or two, probably even a USB port. The communication speeds of these ports vary from port to port. The parallel port or printer port in «Centronics» mode has a forward direction transfer rate of 150KBps. The reverse direction data rate on the «Centronics» mode parallel port is one third of the forward rate, 50KBps. Today’s BIOS limits the RS-232 serial port to 38400bps. The USB ports on the back of most current systems have a maximum throughput of 12Mbps for full speed devices. None of these legacy ports are able to handle the high bandwidth peripherals of today.

Advantages of USB are that the USB controller takes one IRQ; none of the other devices require one. On USB devices, there are no jumpers to configure or hardware settings with which to fiddle. Configuration is very painless and simple. The utopia of plug-and-play operating systems will automatically (in most cases) install the device and drivers for you. USB uses conntector standards for all devices that leads to less confusion for the consumer. Think about all of the connections that are on the back of your typical PC. There is probably a PS2 mouse port, PS2 keyboard port, a nine-pin serial port (or two), a 25-pin printer port, and sound card ports (speaker out, line in, microphone in). That’s a lot of ports to contend with, but what if all the devices used the same connector? If all of those devices where USB devices, you would be that much closer to the Legacy-Free dream system that Intel has been telling us about for the last couple of years.

USB supports multiple devices on the same port. The USB port will technically support up to 127 devices attached to it at one time. Of course, you will have to use some sort of USB hub to connect all of these devices. The USB bandwidth is shared between all devices on the channel. So, if some of your devices reserve a specific amount of bandwidth from the USB port, the amount of devices you can connect will be reduced. To get more bandwidth from USB, you would have to add additional USB ports, usually in the form of a PCI card. USB devices consist of, among other things, keyboards, mice, game controllers, cameras, storage devices, and scanners. If there is a device that you want for your PC, it is likely that is available as a USB device. With all of the devices currently available, especially the ones that require some bandwidth, the standard USB 1.1 specification just doesn’t have the kind of «oomph» that it used to have.

Introduction, Continued

The companies that created the USB specification founded the non-profit organization entitled «USB Implementers Forum, Inc.» The USB-IF was formed to provide a support organization and forum for the advancement and adoption of Universal Serial Bus technology. The Forum facilitates the development of high-quality, compatible USB peripherals (devices), and promotes the benefits of USB and the quality of products that have passed compliance testing.

Just like any other standard (such as IEEE 1394, DTS, WiFi, Dolby, USB, or DVD), there is an official logo for USB 1.0, as well as for the new USB 2.0 standard. Manufacturers put these logos on their devices and packaging to show compliance with the established reference standard. These logos give you some assurance of compatibility and testing. The Hi-Speed USB 2.0 logo is used to show that the device will function correctly with other devices that carry the Hi-Speed USB 2.0 logo. If a device doesn’t have the logo but claims Hi-Speed support, there is no guarantee that it will function with a certified USB 2.0 device. For best compatibility, it is reccomended that you use only certified USB devices.

For a company’s device to bear the official Hi-Speed USB 2.0 logo, the company must be a paying ($2500/yr) member of USB-IF and the device must pass the compliance test procedures defined in the USB-IF Full and Low Speed Test Procedure. The purpose of these test procedures is to evaluate the full and low speed operation of USB silicon that has been incorporated in ready-to-ship products. The documented procedures address the compliance of the three groups listed by applying each group’s respective test procedures:

• Add-in cards, motherboards, and systems
  • Power Provider (Droop/Drop) testing
  • Downstream Signal Quality
  • Interoperability
• Full speed and low speed hubs (no high speed support)
  • Power Provider (Droop/Drop) testing
  • Down Signal Quality
  • Upstream Signal Quality
  • Device Framework Testing
  • Interoperability
  • Average Current Consumption
• Full speed or low speed peripherals
  • Upstream Signal Quality
  • Device Framework Testing
  • Interoperability
  • Average Current Consumption

With the higher speeds of USB 2.0 devices, designers must give attention to Device Packaging, Board Layout, Chassis Grounding, Trace Layout, EMI Remediation, and Data Signal Attenuation/ Jitter.

Hi-Speed USB delivers up to 40 times the bandwidth of a USB 1.1, with the new USB 2.0 delivering an incredible 480Mbps. Hi-Speed USB 2.0 is fully backward compatible with USB 1.1. In fact, you can intermix USB 2.0 and USB 1.1 devices. Of course, for the devices to work at USB 2.0 speed, they would have to be plugged into a USB 2.0 port. Similarly, if you plug a USB 1.1 device into USB 1.1 port, it will operate at USB 1.1 speeds. To achieve the incredible speed that USB 2.0 has to offer, you must have a USB 2.0 capible device plugged into a USB 2.0.

IOGEAR Supplied USB 2.0 Devices

IOGear has clearly become a leader in USB 2.0 solutions. In our report from Comdex (Cable Modem/DSL Router With VPN Support — IOgear), we looked at some of the directions in which IOGear was taking the new USB 2.0 standard. IOGear has been hard at work developing some innovative devices for USB 2.0, and we were lucky enough for them to allow us to put a few of them to the test.

To show the performance gains from USB 2.0, IOGear supplied us with the Impulse Hi-Speed USB 2.0 CDRW (GCD161040) and an IOGear ION 2.0 (GHE125U). The Impulse is an external USB 2.0 CDRW drive, and the ION is a USB 2.0 2.5″ hard drive cage.

While putting them to the test, we really wanted to find out how much true performance difference we would actually see between USB 1.1 and the new USB 2.0. Is USB 2.0 really able to match the speed and performance of IEEE-1394 (FireWire)? We asked this and many other questions during our tests of the Iogear products. In the process of taking this look at USB 2.0, we also were able to give these IOGear products the typical THG once-over, and see if they were worthy of possibily finding a home with your computer.

Impulse — GCD161040 USB 2.0 CDRW

Package contents of the IOGear Impulse USB 2.0 16/10/40 CDRW. It comes with everything you need to enjoy the benefits of USB 2.0. With the included USB 2.0 PCI card, installation and configuration are a snap.

The Impulse is an external USB 2.0 16x10x40 drive with a 2MB Buffer and Burn Proof Technology. In complying with the USB-IF standards, the Impulse is fully backward compatible with USB 1.1, as well. It is compliant with v2.2 of the PC Power Management standard. It is fully plug-n-play compatible and hot swappable.

The Impulse comes with one High Speed USB 2.0 PCI Card (GIC250U), which is sporting the IOGear label. The GIC250U USB 2.0 adapter uses the NEC USB 2.0 chipset. The GIC250U includes a total of five ports; four of them appear on the back of the card and one of them is internal to the card. The internal port is handy in case you want to mount devices in your PC that require USB connectivility, without having to run cables outside your PC. Of course, including the USB 2.0 PCI card in the package will raise the overall price, but, from what we can tell, it won’t up the cost that much.

The burning software that ships with the drive is Nero Burning ROM Version 5. It comes with the standard cables you would expect for an external USB device, one USB 2.0 compliant A to B cable, and a power adapter. The package also contains one blank CDRW, one blank CDR, one 20-CD carrying case, a manual and a standard warranty card.

The Technical Specifications For The Impulse

IOGear does not make the CDRW drive; they produce the IDE to USB 2.0 adapter and case. The Impulse we tested uses a standard ATAPI-E/IDE LITE-ON 16102B CDRW for the drive. This drive does feature firmware that has been modified by IOGear to provide better cross-platform compatibility with USB. The 16102B was a very good drive selection for USB2 capability.

For the CloneCD users out there, this drive’s capabilities are: Best Supported Write Mode — RAW-DAO 96; Best Supported Read Mode for Data — RAW+96; Best Supported Read Mode for Audio — RAW+96; Correct EFM Encoding of Regular Bit Patterns — yes. For people that are just looking for a drive to burn the occasional CD, this drive is more than capable.

The external case that houses the drive is heavy due to the on-board power supply. IOGear has clearly thought about this in advance, because they took the extra step of providing rubber feet on the bottom of the case to reduce movement. The look of the unit was nice, and we liked the choice of colors.

Overall, we found the package to be complete and upgradeable. (Upgradeable is something we didn’t expect, as you will find out later in the article!) For the street price of about $180, it does cost more than your normal internal IDE CDRW, but currently IOGear is offering a $30 rebate on your purchase of the drive, which should help. As far as external CDRW drives go, the GCD161040 was a very complete package, definetely worth looking at.

ION — GHE125U 2.5″ Notebook Hard Drive USB 2.0 External Enclosure

Package contents of the IOGear ION USB 2.0 2.5″ hard drive enclosure.

The ION is an external 2.5″ hard drive enclosure that functions as a USB 2.0 device. It is fully compatible with 2.5″ notebook hard drives in the 9.5mm form factor. The Ion supports the IDE ATA 100 specification. The ION manual indicates that it will support drives up to 30GB in size. After a discussion with Iogear we found out that they have tested the unit with 40GB 9.5mm drives, and the form factor is the limiting factor, not the size of the drive. So, it should be able to support any size drive as long as they are using the 9.5mm form factor. Just like the Impulse it is backwards compatible with USB 1.1 specs. It is fully plug-n-play compliant and hot swappable.

Unlike the Impulse, the ION doesn’t ship with a USB 2.0 PCI card, you have to get that separately. If you don’t have one or don’t want one, the ION will still function as a USB 1.1 device. Of course, IOGear does offer the GIC250U for separate purchase, so coming up with a USB 2.0 card should not be too hard.

In the ION box is the GHE125U hard drive case. It comes with a USB 2.0 A to B cable and a power cable. Of course, it comes with the standard manual, registration and warranty card, as well.

The Technical Specifications For The ION

Of course, as the Ion does not include a hard drive, your performance will vary depending on the hard drive you choose. In our testing, we used an IBM Travelstar model DARA-212000, which was the 4200 RPM 12GB drive.

The ION measures in at .875″ * 3.0″ * 5.5″: as you can see, it isn’t much bigger than your standard 2.5″ hard drive and will still fit in your shirt pocket. The power cable for the ION is a PS/2 pass-through cable. You just unplug your keyboard, plug the pass-through in, and plug you keyboard into it. By using the PS/2 port to power the drive, you don’t have to carry around an AC power adapter.

We found the ION to be a great portable backup device and a good way to move our large MP3 collection between computers. The device is also great for recycling those old notebook hard drives once you upgrade to a larger drive. After all, who wouldn’t like to take that old notebook hard drive and drop it in their pocket? It is nice and compact and sure beats the storage size of your typical flash card.

At the low price of about $70 it can be quite a good investment, but in order to enjoy the full speed that this device has to offer, you will need to select a fast hard drive and must have a USB 2.0 port into which you can plug it.

Test Configuration

To demonstrate the advantages of USB 2.0, we used Nero CD Speed 0.83 Beta and HDTach 2.61 to show the performance increase when switching from USB 1.1 to USB 2.0. As you can tell from the chart below, we didn’t use a top-of-the-line machine to do the testing. Heck, by today’s standards, we didn’t even use a middle-of-the-road machine. We decided to build a low-end machine to show that you don’t have to have the latest P4 2.4G Frag Master to enjoy the benefits of USB 2.0.

Test Results 1

Results — Test 1

In the first test we used Nero CD Speed to test Digital Audio Extraction performance. Nero CD Speed gives you the option to build a DAE test disc under: «Extra;» «Advanced DAE Quality Test;» «Create Test CD.» The CD Speed created disc is what we used during the DAE tests. In stage one of the test, we connected the drive to the motherboard’s onboard USB 1.1 port. In stage two, we attached the drive to the IOGear GIC250U USB 2.0 PCI card. These tests were run to show the performance difference between USB 1.1 and USB 2.0, they were not run to show how the drive stacks up against other drives.

As you can see, the results of the Impulse on a USB 1.1 port are less than stellar. With an average speed of 5.41x, this 40x speedster has its legs chopped out from under it by USB 1.1. This is due to the fact that USB 1.1 has a max throughput of 12Mbps. Due to the limits of USB 1.1, the drive switched to CLV, or Constant Linear Velocity, mode. CLV is when the drive’s RPM changes to maintain a constant data rate.

Results — Test 1, Stage 2

Test 1, Stage 2 — Results of the Digital Audio Extraction test with the Impulse attached to a USB 2.0 port.

After attaching the drive to the USB 2.0 port, you can immediately see a performance increase. The increase in performance is roughly 359% to the better. Due to the increase in bandwidth, the drive switches from CLV mode to CAV mode. CAV, or Constant Angular Velocity, is when the drive’s RPM stays constant and the transfer rate is variable.

Results — Test 1, Stage 3

To really see if USB 2.0 is all it is cracked up to be, and because the Impulse uses a standard IDE drive, we decided to remove the LITE-ON drive from the Impulse cage so we could see how USB 2.0 compares to an IDE device.

Test 1, Stage 2 — Results of the Digital Audio Extraction test with the LITE-ON drive removed from the Impulse and attached to an IDE channel.

As you can tell, we didn’t get the results that one would expect from a 40x IDE drive. The problem appears to lie in the firmware of the drive. According to the LITE-ON web site, the 16102B is full DMA capable, but when we looked at the Secondary IDE Channel properties, we saw that the drive was running in PIO mode. We believe that IOGear made this firmware change to help improve the performance of the drive in a USB enviorment.

With the LITE-ON drive attached to the secondary IDE channel, we see that the drive doesn’t support DMA mode.

Also, the drive isn’t running a standard firmware that is listed on LITE-ON’s website. The other thing is that it is running in P-CAV mode, or Partial Constant Angular Velocity. Partial Constant Angular Velocity is when the drive’s transfer rate increases until it reaches its maximum speed. After maximum speed is obtained, it will slow down to maintain a constant transfer rate.

The drive should have been in CAV mode and the graph should have looked more like the Stage 2 graph.

This isn’t a downfall of the drive; the drive does exactly what IOGear says it will do. It functions perfectly as a USB 2.0 device. Its Digital Audio Extraction scores are very good, and they are comparable to most IDE drives.

Results — Test 1b

Upgrade attempt… We replaced the LITE-ON drive in the Impulse with a Plextor 2410A.

Since we already had the LITE-ON drive out of the Impulse enclosure, we decided to install a Plextor 2410A CDRW into the enclosure to see what would happen. Of course, breaking the warranty seal on the Impulse and installing another drive will void the warranty of your Impulse and IOGear will provide no additional support if you choose to do this.

Test 1b, Stage 1 — Results of the Digital Audio Extraction test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 1.1 port.

As you can see, it worked. The USB 1.1 performance is exactly the same as it was for the LITE-ON drive. Let’s take a look at its USB 2.0 performance.

Results — Test 1b, Stage 2

Test 1b, Stage 2 — Results of the Digital Audio Extraction test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 2.0 port.

Just like with the LITE-ON, the difference in average speed is significant, roughly a 663% increase. Remember, this is not a drive comparison; this is only to show the difference between USB 1.1 and USB 2.0. Next we put the Plextor back in the computer and attached it to the Secondary IDE Channel.

Results — Test 1b, Stage 3

Test 1b, Stage 3 — Results of the Digital Audio Extraction test with a Plextor 2410A attached to an IDE channel.

The numbers from the Plextor on the IDE channel are almost identical to the USB 2.0 numbers. This is what we expected to see from the LITE-ON drive, but, as we said, we think that is a firmware issue with the drive.

Test Results 2

Results — Test 2

In the second test, we used Nero CD Speed 2000 to show the differences between USB 1.1, USB 2.0 and IDE in CD writing performance.

Test 2a, Stage 1 — Results of the CD burning test with the Impulse attached to a USB 1.1 port.

As with the USB 1.1 Digital Audio Extraction test, we see that USB 1.1 will not let the drive do what it is capable of doing. This drive is a 16x writer; with an average write speed of 3.03x, we are seriously considering taking on a quest for a motherboard with onboard USB 2.0.

Results — Test 2, Stage 2

Test 2a, Stage 2 — Results of the CD burning test with the Impulse attached to a USB 2.0 port.

15.96x is close enough to 16x to call it 16x. It was nice to see that the drive is doing what it is capable of doing. Let’s hope that we don’t see any firmware related issues when we drop it on the IDE channel.

Results — Test 2, Stage 3

Test 2a, Stage 3 — Results of the CD burning test with the LITE-ON drive removed from the Impulse and attached to an IDE channel.

Once again the LITE-ON drive is connected to the secondary IDE channel. Unlike the Digital Audio Extraction test, at .06%, the drive’s average speed IDE write numbers are only slightly better than the average speed USB 2.0 write number.

The LITE-ON drive performed very well in the write tests. We saw almost a 427% increase in performance compared to USB 1.1. In comparing the USB 2.0 to IDE, we saw less than 1% to the advantage of the IDE controller.

Results — Test 2b

Just like we did with the DAE test, we put the Plextor 2410A in the Impulse enclosure to try and give you a better understanding of the differences between USB 1.1 and USB 2.0.

Test 2a, Stage 1 — Results of the CD burning test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 1.1 port.

By looking at the three previous USB 1.1 tests, we should know what to expect when we attach the Plextor. With an average write speed of 5.50x, there would be no need to have anything better than a 6x writer. But, just as in the other tests, this is no fault of the drives, the maximum throughput of USB 1.1 is to blame.

Results — Test 2b, Stage 2

Test 2a, Stage 2 — Results of the CD burning test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 2.0 port.

True to form, the Plextor kicked out its max transfer speed of 24x. You may wonder why the graph is a stair step and not a diagonal line as seen in the DAE tests. CD speed reported that the drive was running in P-CAV mode. The graph does represent P-CAV results; P-CAV results would look more like the results from Test 1, Stage 3. The stair step results look more like Z-CAV mode. Z-CAV, or Zoned Constant Linear Velocity, is when the drive transfers at a certain rate depending on the location of the laser on the disc. The results show that, for the first 2 minutes, the drive is burning at 16x, and then it starts to ramp up to 20x. From the six-minute mark to the twelve-minute mark, the drive writes at 20x. At about the twelve-minute mark, the drive ramps up to full write speed. At sixteen minutes into the disc, the drive is burning at 24x.

Results — Test 2b, Stage 3

Test 2a, Stage 3 — Results of the CD burning test with a Plextor 2410A attached to an IDE channel.

On this test, USB 2.0 beat out the IDE controller by 0.5%. Being less than 1%, the difference isn’t much to talk about, but it shows that USB 2.0 is a real product and it has the bandwidth to back it up.

Test Results 3

Results — Test 3

In test 3, we ran HDtach with the ION drive attached to both the USB 1.1 and the USB 2.0 ports. We then removed the IBM drive from the ION enclosure and attached it to the secondary IDE channel of our test machine via a 2.5″ to 3.5″ adapter.

Test 2a, Stage 1 — Results of the CD burning test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 1.1 port.

From just looking at the graph, you may think that the ION kicked butt on the USB 1.1 port. What you are really seeing is that the drive transferred near max throughput for the USB 1.1 port. With an average read speed of 889.1 kbps and a CPU utilization of 8.0%, you really wouldn’t want to the drive for more than backup operations.

Results — Test 3, Stage 2

Test 2a, Stage 1 — Results of the CD burning test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 1.1 port.

With the ION attached to the USB 2.0 port we get much better performance out of the drive. An average read speed of 10652.5 kbps is 1098% better than the 889.1 turnout from the USB 1.1 port. The CPU utilization was also lower than USB 1.1, at 3.9%. With these transfer rates you can use the drive for whatever you want. Whatever you can do with an IDE drive, you can do with the ION on a USB 2.0 port, you won’t be limited by the USB controller.

Results — Test 3, Stage 3

Test 2a, Stage 1 — Results of the CD burning test with a Plextor 2410A mounted in the Impulse cage and attached to a USB 1.1 port.

With the IBM drive removed from the ION enclosure and attached to the secondary IDE channel, we saw an average transfer rate of 10726.9 kbps. The CPU utilization fell to 3.6%. As you can see, the numbers are very similar to those of the USB 2.0 port.

Conclusion

Overall, the Impulse is a good product; the included USB 2.0 card is a very nice and needed addition. Though it did not fair well on the USB 1.1 port and the IDE channel, the Impulse did function perfectly as a USB 2.0 device. The LITE-ON drive that is in the Impulse should fill the needs for just about every user. We did show that, in its current production version, the Impulse is upgradeable, as demonstrated when we installed the Plextor in the Impulse enclosure. The ability to upgrade the drive will give new life to the Impulse when you start thinking about putting it on the shelf and going with a faster drive. Of course, upgrading your Impulse drive will void the warranty.

The ION enclosure is a nice product; the only problem is that very few of today’s PCs have USB 2.0 ports. The ability to take your data in a 2.5″ hard drive is very appealing, but the lack of a USB 2.0 port on your computer will limit full utilization of the drive. Until USB 2.0 is more readily available, the ION enclosure wouldn’t give you much more than a backup drive for your laptop.

The results show that USB 2.0 has more (a lot more) bandwidth than USB 1.1. There are a lot more possibilities with USB 2.0 than USB 1.1. You are no longer limited to keyboards, mice, printers, scanners, or low frame rate web cams. Just like with FireWire or IEEE 1394 (400Mbps), digital video is now very much an option for good old USB. USB 2.0 has the advantage over FireWire. We are curious to see if the USB designers can keep up when IEEE 1394b devices are released. With 1394b, you will see the maximum transfer rate of 400Mbps jump to 3.2Gbps by the end of 2003.