January 10 marks the release of the first 160MBps SCSI cards. Adaptec—by many accounts, the industry leader in SCSI cards—is the first company to bring them to market with its Ultra-160 SCSI cards. These cards are twice as fast as Adaptec’s 80MBps Ultra-2 SCSI cards. This speed increase didn’t require a significant change in SCSI technology. The major technology shift in SCSI cards occurred between the 40MBps Ultra Wide SCSI and the 80MBps Ultra-2, explained Ravi Chalaka, Adaptec’s director of marketing for distribution channel products. At that time, Adaptec dropped the 1-line, single-ended technology and changed to 2-line, Low Voltage Differential (LVD) technology. LVD SCSI sends over two lines, using the voltage differential to transmit data. This change increased the data-transfer speed from 20MHz to 40MHz. With Ultra-160, Adaptec remains settled on LVD and 40MHz technologies. The main difference from Ultra-2 technology involves dual-edge clocking. With Ultra-2, “data was loaded only on the down part of the wave,” explained Chalaka. With Ultra-160, “data is loaded on the up and the down part of the wave.” Dual-edge clocking is the number one feature of Ultra-160. Adaptec is also adding cyclical redundancy check (CRC) error-checking to the SCSI cards. Ultra-2’s LVD technology made error-checking unnecessary for 80MBps transfers; as the speed increases, however, error-checking becomes more important. Chalaka outlined a fascinating, highly aggressive strategy: Adaptec will completely replace its Ultra-2 SCSI cards with the new technology. Adaptec will stop all production of Ultra-2 cards by March. In previous upgrades, Adaptec offered both the new technology and the older one, giving customers a choice. “By March,” said Chalaka, “we hope to stop shipping what the customer is currently buying. We are replacing six older products with four newer products.” According to Chalaka, “the price of the new product will be no greater, and in some cases, lower than the Ultra-2 cards.” Adaptec is eliminating the traditional move of offering older technologies for less money—an interesting strategic decision. “Everything will be Ultra-160,” explained Chalaka, “because it’s completely backward-compatible.” He added that this policy applies only to the premium hard-disk SCSI cards. Lower-technology SCSI cards will still be available to connect peripherals such as scanners and recordable CD drives. Chalaka said that the SCSI standards body has plans for 320MBps SCSI in 2 years and 640MBps SCSI in 4 years. The leading-edge SCSI standard will continue to have faster throughput than its fibre channel counterpart.
