Serial bus gets serious with USB 2.0: FireWire says: what? Me worry? - Connectivity

Computer Technology Review,  March, 2002  by Joshua Piven

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You may have sensed it late last year, and really felt something in the air in January. By now, you should be well aware that 2002 is not going to be just any old year. In fact, it is the "Year of USB 2.0." Well, at least according to the USB Implementers Forum (USB-IF), the trade group that develops Universal Serial Bus standards.

Okay, so maybe it isn't the Winter Olympics. But the long-awaited, much-anticipated arrival of USB version 2.0 is upon us, and some observers are already talking about the death of FireWire (IEEE 1394) as the interface of choice for bandwidth-hungry peripherals. But while the throughput improvement for USB is substantial, FireWire is not exactly standing still. And the USB-IF has another new technology in development: this time, Bluetooth may be in the cross hairs.

USB: Ultra Slow Bandwidth?

USB 2.0 is the first major overhaul of the Universal Serial Bus specification since it was introduced seven years ago. At that time, the interface was tasked primarily with supplanting the decade-old serial port, as well as ports like the PS/2 which are primarily used for pointing devices. It was thought that, with 12Mbps throughput, USB would offer plenty of speed for add-ons such as speakers, mice, joy-sticks, CD-ROM drives, and printers. The SCSI-like ability to connect multiple devices to a smart interface--using a USB hub--was revolutionary at a time when most PCs were equipped with just two or three serial ports and a parallel port.

Further, the logic went, the PC would never make it as a home appliance aimed at the non-technical user until the dreaded "case-crack" (the opening of the system to add cards) was eliminated. Sure, the power user and the professional would still tinker with the innards of a system, but USB would enable a whole range of new devices to be purchased and enjoyed by even the casual computer user.

But like most good technologies, USB 1.0 became a victim of its own success. While it took several years before the interface was added to the OS and motherboards, once it was, a landslide of peripherals hit the market: scanners, printers, digital cameras, floppy replacement drives, and PDAs all could now be attached in seconds, with nary a manual in sight. But soon, as users began to transfer huge image and audio files, 12Mbps was just too slow (ever try transferring a few hundred megabytes across a USB connection?)

USB 2.0 is an enormous speed increase over the earlier version of the specification. 2.0 offers throughput of as much as 480Mbps, or 40 times faster than USB 1.1. This means that USB is now appropriate for demanding peripherals such as CD-R, CD-RW, and DVD-R drives, as well as add-on hard drives.

Late last year vendors began shipping USB 2.0-compliant devices. However, tuned USB 2.0 drivers (and systems) have just begun to hit the market, and Microsoft added OS support for Windows XP via a Windows Update download in late January. (At press time, support of USB 2.0 in Windows 2000 was scheduled to be available by late March. Windows 9.x and NT 4.0 will not support version 2.0.)

While some PC OEMs have begun adding USB 2.0 support to systems, the faster interface is expected to truly take off when Intel adds integrated USB 2.0 support to its next core logic chipset, expected by mid-year. Intel has already begun to add 2.0 support to system boards. At CES in January, the company announced two P4 desktop boards (D850MVSE and D845BGSE) that each support up to five USB 2.0 ports.

Lighting The Fire Under FireWire

While version 2.0 of USB was developed to increase the versatility of the original interface, as usual there was also a solid business reason to speed things up. Apple Computer Corp. owns many of the 1394 patents: the interface was developed by Apple engineers in the 1980s and only later submitted to the IEEE for adoption as a standard. The term "FireWire" is, in fact, trademarked by Apple and the company charges a licensing fee of 25 cents for each implementation of the technology. (1394 technology is also known as i-Link, which is trademarked by Sony.) And while USB 2.0 is slightly faster than the original 1394 specification (480Mbps and 400Mbps, respectively), IEEE 1394b (as the newest version is known) will offer a blistering 3.2Gbps of throughput over fiber cable, which puts even USB 2.0 to shame.

"Without USB 2.0, I think you would have seen the printer and camera guys switch to FireWire," says Michael Johas Teener, who was the chief architect of Apple Computer's FireWire development effort in the 1980s. Teener is the originator of the 1394b gigabit effort and is currently Chief Technology Officer at Zayante Inc., a maker of 1394 silicon and software tools.

Unlike USB 2.0, Windows XP supports 1394b out of the box, so no point upgrades are necessary to enjoy it, It should be noted, however, that 1394b-based devices are not expected to hit 3.2Gbps for at least 18 months. Texas Instruments and Agere have demonstrated 1394b-based devices running at 800Mbps; realistically, we can expect to see commercially available products operating at about 800Mbps over copper this year, with a doubling to 1.6Gbps in early 2003 and then another doubling sometime later that year.