6.14.7Transmitter Pre-Compensation with Cutback

This is an open-loop method of compensating for some of the signal loss that is most severe on the first part of a signal’s transition.

6.14.8Free Running Clock (FRC)

FRC is used to improve integrity of the clock signal by removing inter-symbol interference (ISI). By having a clock running at a constant neutralized. The free running clock is restricted for use with DT information unit transfers at 320 megabytes per second.

6.14.9Skew Compensation

Skew compensation of data signals relative to the clock signal; an Ultra320 SCSI device can establish skew compensation simultaneously for each of the received transitions on the data lines so that they occur at the correct time relative to the clock.

6.14.10Information Unit Transfers

IUT (or “IU Transfers,” also known as “packetized transfers”) is a method to encapsulate non-data information (like commands sent from the initiator to the target and status sent from the target to the initiator) into packets and transfer those packets at the maximum negotiated data rate of up to 320 megabytes per second. A method to transfer packets for a number of I/O processes without an intervening physical disconnection. A method to minimize overhead by eliminating several bus phase changes per I/O process.

6.15HOT PLUGGING/REMOVAL AND INSERTION OF SCSI DEVICES

The Maxtor Atlas 10K V SCA low voltage differential (LVD) disk drives are designed for use in “Hot Swap” applications within a properly designed and configured SCSI system. With care, system integrators can design storage arrays and/or SCSI buses using Maxtor Atlas 10K V disk drives that are “Hot Swap Case 4" tolerant.

Case 4 is defined as follows:

•Devices are powered and the bus may have active I/O processes ongoing, but the device being removed or inserted must be idle (no ongoing I/O processes during the insertion/removal).

•Ground connections to the drive must be made and maintained for 1 millisecond before, during, and 1 millisecond after the insertion/ removal. The SCA-2 connector used on the Maxtor Atlas 10K V disk drive meets this requirement.

•Device circuitry connected to bus pins must remain “glitch” free during power up or power down.

Note: In a multimode environment, any insertion or removal that changes

the bus mode causes a transceiver mode change reset event.

6-12 Maxtor Atlas 10K V