HP Workstation x2000 hp workstation x2000 - Technical Reference and Troublesho - Page 135

Hardware Components SCSI Adapter Cards Additional SCSI Card Features The following table describes features of the Adaptec SCSI card. Feature Double Transition Clocking Cyclical Redundancy Check Domain Validation Description Changes the digital protocol to use both edges of the SCSI request/acknowledge signal clock. Allows designers to use Ultra2 cables. The signal in an Ultra2 SCSI runs a 40MHz, whereas data runs at only 20MHz or 80MB/sec on a 16-bit wide bus. Using both edges of the same signal at 40MHz, you can increase the data rate to 40MB/sec or 160MB/sec on a 16-bit wide bus. Provides extra data protection for marginal cables that are connected to external devices. The Ultra3 SCSI cyclical redundancy check detects all: • Single-bit errors • Double-bit errors • Odd number of errors • Burst errors up to 32-bits long Tests networks, cables, backplanes, terminators, and hard disk drives to ensure that the environment is operating at required specification. If reliability is at risk, the transfer speed is lowered. Chapter 5 135