Mixed reviews greet Ultra160/m SCSI

Posted on December 01, 1998

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Mixed reviews greet Ultra160/m SCSI

By Zachary Shess

Three months after announcing and leading the cause for Ultra160/m SCSI, Quantum and Fujitsu appear to be the only hard-disk-drive manufacturers backing the interface, which is based on the Ultra3 SCSI standard.

Among the leading disk-drive vendors, IBM and Seagate plan to ship Ultra3 SCSI products in late 1999. Western Digital will support Ultra3, but would not say when. Maxtor declined comment. While officials with these companies stopped short of rejecting Ultra160/m SCSI, all say they will deliver products based on the needs of their large OEM customers.

One top-tier OEM, Compaq, plans to use Ultra3. "Compaq will deliver Ultra3-based solutions only when it is proven to provide significant benefit to our customers and has stabilized to the point that it can support the reliability and functionality we demand for our systems," says Jeff Jenkins, a marketing manager in Compaq`s storage products division.

In mid-September, a group of vendors including Quantum, Fujitsu, Hewlett-Packard, Adaptec, and Mylex defined Ultra160/m SCSI as a set of "common denominator" features that include double transition clocking, cyclic redundancy check, and domain validation. Proponents maintain that Ultra160/m SCSI answers industry needs for additional speed (160MBps vs. Ultra2 SCSI`s 80MBps), manageability, and backward compatibility. While detractors acknowledge that Ultra160/m will improve on Ultra2 SCSI, the omitted packetization and quick arbitration/select features could prevent the 160MBps data rates from occurring.

"Ultra160/m is really a half-step between Ultra2 and Ultra3, because in order to be assured of sustained 160MBps data rates across the parallel bus, you must have the other two missing attributes--data packetization and quick arbitration and select," says Shawn Hook, a product marketing manager with Seagate Technology. "Otherwise, there is too much overhead on the bus and you can`t service the drives fast enough to sustain the data rates."

Jim Porter, president of Disk/Trend Inc., a market research firm in Mountain View, CA, says Quantum`s announcement of 160/m SCSI drives in October is an attempt to be first to market with next-generation SCSI product. "They were also anxious to get it out there because they could say it`s faster than Fibre Channel. But there is no immediate big push in the industry to go to 160MBps SCSI," says Porter.

With the next generation of SCSI up for debate, does this make Fibre Channel the ultimate winner? "Unless you have a crystal ball, it`s very difficult to predict when Fibre Channel will become the dominant technology," says Hook. "Once Fibre Channel and parallel SCSI become equal in total implementation costs, people will switch over to Fibre Channel because of its ease of use, better connectability, and elimination of cabling restrictions."


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