SCSI Trade Association Envisions Future of Ultra

The SCSI Trade Association (STA, will announce its roadmap to increase current transfer rates four-fold on Tuesday. The latest Ultra 3 SCSI runs at 160 MBps, but new plans will double that within the next two years (Ultra 4) and push the rate to 640 MBps by 2003 (Ultra 5).

"We felt we needed to take some time to share our vision about where the technology was going," says Harry Mason, president of the STA. "At this point in time, we're not formalizing the features and functionality in Ultra 4 and Ultra 5 SCSI, but we believe the technology is meetable.

Asked if he felt Windows 2000 was having any effect on the use of SCSI, Mason says independent of the OS, SCSI has obtained a very robust position in the server space and that more users will gravitate to SCSI because of its "out-of-the-box" usability.

Several trends support the industry's need to enhance SCSI's capabilities. Higher processor and memory speeds demand higher data transfer rates from mass storage devices, requiring that SCSI continue to evolve to faster performance. For example, Gigabit Ethernet can require data transfer rates up to 200 MBps. Enhancements to the PCI bus to increase bus width to 64 bits and speed to 66 MHz, along with alternatives to the PCI bus, also will require increasing data movement.

Mason says there's a Moore's Law in the performance industry that data transfer rates double every 2.2 years. "Whether we can follow that curve remains to be seen but we need to be aware of it and support it," Mason says. Further driving the SCSI performance evolution is the exponential increase in data storage requirements for servers, a result of the widespread use of the Internet and of corporate databases that often incorporate multiple data types such as text, graphics, audio and video.

Last September, the same board approved features for the Ultra 160/m SCSI, based on the Ultra 3 interface. The "m" stood for manageability and it's those manageability features that are being implemented to improve speed. These features include Cyclic Redundancy Code (CRC) and domain validation. CRC protects data from being lost in the event of a poor connection during hot-plugging a new drive into a system. Domain validation provides a new method for ensuring compatibility and that data transfers happen at the highest possible rate. If this rate is not possible then the device can shift to a lower speed before data transfer begins, allowing SCSI to tune its performance to the highest performance the system will support.

Member companies also are developing manageability software to track errors and define how to make system adjustments to ensure maximum overall performance. New SCSI applications and configurations include static and dynamic switches, which allow multiple systems to be connected to multiple drive arrays. There are also expanders, hubs and bridges, which allow SCSI to be used for longer distances and reduce loading problems. -- Brian Ploskina, Assistant Editor

About the Author

Scott Bekker is editor in chief of Redmond Channel Partner magazine.

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