Get set for arrival of new serial interface

Get set for arrival of new serial interface – Ieee 1394

Grant Buckler

Multimedia will probably be the driving force behind a new serial interface that has just begun edging into the computer market. Officially, the new interface is prosaically named IEEE (Institute of Electrical and Electronics Engineers) 1394. Apple Computer Inc. has given it a name with a little more pizzazz: FireWire.

Work on the project began more than five years ago, according to Jonathan Zar, business manager for FireWire at Apple in Cupertino, Calif. However, it will only hit the market in earnest some time later this year.

One reason 1394 is interesting is speed. Initially it will run at up to 200 megabits-per-second. A second generation will double that speed to 400 megabits per second, according to Robin Selden, director of product marketing in the personal input/output business unit of Adaptec, Inc., in Milpitas, Calif.

What makes the interface interesting for multimedia, though, is the fact that it is isochronous. That word seems to crop up a lot lately in connection with PC communications. It means equal in time.

An isochronous interface delivers chunks of data of a fixed size at fixed intervals.

This is in contrast to asynchronous interfaces, whose throughput varies. Zar likens the problem to a circulatory disorder in the human body.

Like blood dots, bottlenecks in networks cause data to back up. “There’s clotting throughout the system” in today’s computers, he says. Why is that suddenly important? Because of multimedia, which involves video and audio signals that make delays very noticeable. An isochronous interface means you don’t get jerky motion or awkward pauses in a video clip while your computer waits for more data to arrive.

So, those involved with the 1394 effort today expect it will catch on first in multimedia applications and in devices such as digital video cameras, video capture cards and so on.

Zar says desktop publishing is another likely application. The reasons for that are the speed and convenience of the interface and the fact that it will allow peer-to-peer data movement.

For instance, images from a document scanner could be spooled directly to a computer’s disk, creating a sort of “digital photocopier,” he says. Selden also expects 1394 to catch on fairly early in document imaging.

Use of 1394 for multimedia and desktop publishing will probably create a demand for mass storage peripherals that support it, Zar adds.

Eventually, Selden maintains, it should replace the Small Computer Systems Interface (SCSI) and Integrated Drive Electronics (IDE) interface standards.

Another use for the interface might be in portable and handheld devices. Because it is not only fast but compact, FireWire might be a good interface for linking notebook computers to docking stations, for example.

And Zar says it will also have uses in niches such as test and measurement.

Another point about 1394 is ease of installation. Like SCSI, it allows multiple devices to be daisy-chained. When you add another device to the chain, the interface will automatically detect the change and re-initialize itself.

The IEEE 1394 standard is virtually complete. Though there has already been some activity – Sony Corp. has launched a video camera that supports the 1394 interface – Gary Hoffman, founder of 1394 developer Skipstone, Inc., in Austin, Tex., expects the technology to get moving in earnest this fall, with a flurry of product announcements at the Comdex/Fall computer show in Las Vegas.

Grant Buckler is a Kingston, Ont.-based freelance writer. He can be reached at the following address:

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