USB Gains Momentum

Mark A. KellnerSpecial to GCNJust as no man is an island, as poet John Donne wrote a couple of centuries ago, no computer stands alone. Along with modem or LAN connections, there's a whole raft of devices clamoring for attention and attachment.Scanners, printers and other peripherals want in, and more and newer devices are coming, almost daily. Can you say Pocket PC?One challenge, however, is that most PCs built before 1997 have a limited number of options for these connections. A PC may have one or two standard serial ports and one parallel port. But that's usually about it.Users have been able to add other serial and parallel ports on computers via add-in cards, but that practice leads to something many power users have come to know and hate: interrupt request, or IRQ, conflicts.PCs allow only 16 IRQ lines to signal the CPU chip that a peripheral event, or operation, has begun or ended. Two devices can't share the same IRQ line, and some IRQs are reserved for various system functions and devices, such as keyboards, floppy drives, parallel printer ports, hard drives and so on. Add too many peripherals, and you end up with conflicts. The PCI bus, first introduced in late 1993, allowed devices to share an interrupt, easing the bottleneck somewhat.But at the heart of the conflict remain the poor speeds that other ports offer. Traditional serial and parallel ports can be fast, but not as fast as either current or pending Universal Serial Bus connections.At a recent USB developers' conference, a Hewlett-Packard ScanJet scanner using a USB 2.0 device core from inSilicon Corp. of San Jose, Calif., transmitted a scanned image to a PC at bursts of 480 Mbps. That's 40 times faster than the current USB 1.1 specification, and far quicker than a serial- or parallel-port connection.During the last three years, USB has rapidly caught on among PC makers and users. It uses a one-size-fits-all plug and allows hot-swapping of peripherals and the connection'at least, theoretically'of up to 127 devices. And despite a few fits and starts, the high-speed, universal interface for printers, CD-ROM drives, digital still and video cameras, telephones and even personal digital assistant synchronization has grown into a successful, vital force in computing.Today, just about every new PC or Macintosh has a USB port. The connection is a staple on so-called legacy-lite and legacy-free PCs from Compaq Computer Corp., HP and IBM Corp., and it is one of the common elements new Apple Macintosh desktop and notebook PCs share with their PC counterparts.Just about every kind of computer peripheral is available with a USB connector. Cygnion Corp. of Irvine, Calif., and Nortel Networks Corp. of Brampton, Ontario, offer desktop telephones and software to interface with PCs via USB connections. And cameras from Casio Inc.use the USB port and software from Zing Networks Inc. of San Francisco to upload images directly to Web sites for business and private use.As the HP scanner demonstration indicates, the best uses for USB may be yet to come; products supporting the Version 2.0 standard are due later this year. According to the USB Implementers Forum, an industry trade group, the new standard will boost the speed of the peripheral-to-PC connection from the 12 Mbps of USB 1.1 to up to 480 Mbps. The higher bandwidth will support the most demanding PC user applications, such as digital image creation and Web publishing, in which multiple high-speed peripherals will run simultaneously.USB 2.0 is expected to gradually replace USB 1.1, which is already a ubiquitous connector on PCs for such peripherals as keyboards, mice, digital joysticks, floppy drives, digital speakers and low-end printers. The final USB 2.0 specification was released at the annual Windows Hardware Engineering Conference in New Orleans last April.According to Pat Gelsinger, desktop products group vice president at Intel Corp., the new standard came to market quickly. The USB 2.0 Promoter Group, consisting of Compaq, HP, Intel, Lucent Technologies Inc. of Murray Hill, N.J., Microsoft Corp., NEC Technologies Inc. of Itasca, Ill., and Philips Semiconductors N.V. of Amsterdam, developed the technology.The rapid development of the USB 2.0 specification can also be attributed to the evolutionary nature of the technology, Gelsinger said.'Since the high-speed mode has the same basic architecture of USB, migrating existing USB peripherals to USB 2.0 is a much easier task than transferring to a brand new technology,' he said. 'Also, because USB 2.0 will be fully forward- and backward-compatible with current USB systems and peripherals, working with existing cables and connectors, consumers have the benefit of using devices they already have.'The first USB 2.0-enabled systems and peripherals are expected in the marketplace late this year, according to the USB Promoter Group. Broad deployment is expected next year.USB 2.0 complements high-performance PCs and user applications, enabling them to be more productive. Scanners, for example, can create a high-resolution digital image in seconds with USB 2.0, rather than the minutes required with USB 1.1. The time needed to download a set of digital photos also will be slashed from minutes to seconds.Users will also be able to back up 1G of data from a PC hard drive in less than a minute with USB 2.0, a task that took about 30 minutes using USB 1.1, the trade group said.USB 2.0 will lead to the development of higher-performance peripherals that will bring new applications to the PC, Gelsinger said.As with many things in computing, however, USB developments do not take place in a vacuum: The IEEE 1394 standard is also a popular input/output standard. USB promoters claim the USB 2.0 standard and IEEE 1394, also known as FireWire, differ primarily in the device to which an application is attached. USB 2.0 supporters say it is the preferred connection for most PC peripherals, and IEEE 1394's primary target is audiovisual consumer electronic devices such as digital camcorders, VCRs, DVD players and TV sets.There's room for debate on that topic. According to a recent report from Cahners In-Stat Group, an industry researcher in Newton, Mass., FireWire is gaining popularity.In-Stat reported that shipments for devices with IEEE 1394 ports grew to over 12 million last year, from 3.5 million in 1998. The primary growth driver was IEEE 1394 adoption by PC makers. PC manufacturers that now support IEEE 1394 include Apple Computer Inc., Compaq, Dell Computer Corp., Fujitsu America Inc. of San Jose, Calif., Gateway Computer Corp., HP, NEC, Panasonic Personal Computer Co. of Secaucus, N.J., Sharp Electronics Corp. of Paramus, N.J., and Sony Corp. of America of Park Ridge, N.J.Mark Kirstein, In-Stat's vice president of research, said, 'As more peripherals become available, and the installed base of PCs with 1394 grows, applications will continue to expand' beyond FireWire's stronghold in digital media and despite the industry push for USB 2.0Users with performance needs such as multimedia Web site production will likely want both features on their systems. But many business PCs, such as HP's recently introduced eVectra or Compaq's iPaq desktop, have shunned FireWire in favor of USB.There's little doubt that USB connections are important for computer users and information technology managers.The connectivity for a variety of devices is here now; maturing systems for the new specification will be a challenge for the months ahead.