HP I Dual Channel Ultra160 SCSI Host Adapter A6829A manual Maximum Data Transfer Rate, Tip

Installing the A6829A Adapter

Specifying SCSI Parameters

Maximum Data Transfer Rate

The firmware suggested default for the A6829A adapter’s maximum data transfer rate is the adapter’s maximum speed (160 MB/s). The A6829A can communicate with all LVD or SE devices that have speeds up to 160 MB/s. This includes the following speeds (synchronous communication over a Wide bus):

	•	Fast (20 MB/s)
	•	Ultra (40 MB/s)
	•	Ultra2 (80 MB/s)
	•	Ultra160 (160 MB/s)
	The actual transfer rate between the adapter and a SCSI device depends
	on the transfer rate that was negotiated between the adapter and the
	SCSI device. However, the actual rate will never be greater than the
	maximum data transfer rate set for the adapter.
	For example, if you set the A6829A’s maximum data transfer rate to
	NOLIMIT (which is same as 160 MB/s, in this case), and then connect a
	disk drive that has a maximum data transfer rate of Ultra2 (80 MB/s),
	the actual transfer rate will be 80 MB/s.
	HP recommends that you always set the A6829A’s maximum data
TIP
	transfer rate to MAX or NOLIMIT (whichever is applicable to the system),
	unless you are trying to debug a communication problem between the
	adapter and a specific SCSI device. Using MAX or NOLIMIT allows the
	adapter’s maximum transfer rate (160 MB/s) to be used.

You can set the A6829A’s maximum data transfer rate in two ways, as shown in Table 2-2 on page 24.

To set the maximum data transfer rate for A6829A HBA installed in PA-RISC based system, see “Setting Maximum Data Transfer Rate for A6829A Host Bus Adapter Installed in PA-RISC Based System” on page 30.

To set the maximum data transfer rate for A6829A HBA installed in Itanium-based system, see “Setting Maximum Data Transfer Rate for A6829A Host Bus Adapter Installed in Itanium‚-Based System” on page 34.

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