If you've been in the computer business for a while, you can painfully remember when serial RS-232 ports could barely handle 28Kbps (kilobytes per second). The RS-232 serial port standard was loose enough that you could have “compatible” devices that you could never, ever physically connect with each other. How things have changed! Now, USB 3.0 can wheel and deal up to 625 Mbps. So, why is it so hard to find USB 3.0 ports and devices?
You already know that Universal Serial Bus (USB) is now the universal interface for computer peripherals, whether that’s a local printer or a USB-powered jellyfish mood lamp. Many devices only have USB ports.
The USB technology has come a long way since 1995, when USB 1.0 could only transfer 12 Megabits per second, and Windows NT lacked support for the new “standard.” It was only when USB 2.0 showed up in 2000, with its 480Mbps data transfer, that the days were numbered for other interfaces, including PS/2, serial, parallel, and even FireWire. Today, USB 3.0, also known as SuperSpeed USB, with its 5 Gigabits per second (Gbps), is finally catching on.
The improvement isn’t only in the standard’s version number. USB 3.0’s “SuperSpeed” 5Gbps is more than ten times faster than USB 2.0’s top theoretical speed of 480 Mbps. USB 3.0 supports asynchronous data transfers, which means that (unlike USB 2.0) it doesn't need to wait to poll a USB device every time it ships data one way or the other.
In addition, USB 3.0 includes a new transfer method called bulk streams, which lets USB support multiple data stream transfers. The net effect is that the protocol does much better with huge data transfers. Such as, say, if you’re viewing an high-definition movie that resides on an external hard drive.
USB 3.0 has more than just pure speed going for it. USB 3.0, like the other USB standards before it, lets you power up devices. USB 3.0, however, takes external power management to a whole new level.
First, USB 3.0 supplies 50% more power to devices. With this you can power not just thumb drives but also external drives like hard and CD/DVD drives. As lightweight laptops drop optical drives, that last advantage may become increasingly important.
Second, the USB 3.0 standard uses interrupts now instead of polling when a device is plugged in. With polling, when you plug in a USB device, your PC keeps constantly checking to see if needs anything, like a sometimes over-friendly waitress. Polling can keep the computer from going into low power states and can quickly drain a battery. Even a plain-old USB mouse can do this. That's bad news on a laptop. By using interrupts, USB 3.0 doesn't waste time or energy on an idle device. This can really save you some battery life.
So why aren't you using USB 3.0 yet? There are several reasons.
USB 1.0 and 2.0 cables and ports were interchangeable. Though, of course, the connection would only go as fast as USB 1.0's 12Mbps.
But with USB 3.0, even though the plug and PC connections look the same at a casual glance, they're not as compatible as the older models. Instead of the earlier version’s four wires, the USB 3.0 cable has eight wires. One is power, one is for the ground, two are for USB 2.0 data, and the remaining four wires are for “SuperSpeed” data. If you take a closer look, you'll see that one edge of the plug is colored blue. The end that plugs into your USB 3.0 device — drive, scanner, printer, camera, whatever — is incompatible with a USB 2.0 device. So, while you can plug a USB 2.0 device with a USB 2.0 cable into a USB 3.0 port or a USB 3.0 device with a USB 3.0 cable into a USB 2.0 port, you can't use a USB 3.0 cable to connect a USB 2.0 device. Got that? The bottom line is you can't mindlessly switch USB cables the way you used to.
Then there’s the matter of manufacturer support. Like the replacement of BIOS with UEFI, you only get hardware features when someone else builds it in. For USB 3.0, the critical problem is that Windows 7, even with SP1, still doesn't natively support USB 3.0. You can use USB 3.0 ports and devices with the right device drivers, but in 2011, what Windows user worries about device driver compatibility? Mac users have the same problem. Even Lion doesn't have built-in USB 3.0 support. Curiously enough, Linux is the only mainstream operating system with USB 3.0 support baked in.
It also hasn't helped any that it was only this year that Intel finally committed to supporting USB 3.0 on an actual product line. Intel will ship the “new” USB on its Ivy Bridge chipset, but Ivy Bridge isn't due to appear until March 2012. In part, Intel's been slow to move on USB 3.0 because the silicon giant is supporting its own, even newer, high-speed interface, Thunderbolt.
Thunderbolt is Intel specific, while USB 3.0 is an industry standard. In the short run, you're going to see a lot more USB 3.0 ports and devices than Thunderbolt ones.
For example, HP has been shipping laptops with USB 3.0 since early 2010. HP, like other major PC vendors, supplies drivers for own its USB 3.0 ports so you won't need to worry with devices working with your laptop or PC. HP also supplies USB 3.0 drivers for Windows 7 and well as for Windows XP; or you can add on a USB 3.0 card to your existing PC such as the HP SuperSpeed USB 3.0 PCIe card.
In short, USB 3.0 may have taken its own sweet time in getting here, but the PCs, the cards, and the devices are all here now. And, between its speed and power-support, when it comes time to buy a new PC, you should make sure it has USB 3.0 inside before buying it. You'll be glad you did.
