Avago Technologies LSI53C1020 - Manual (Page 21)

Benefits of Ultra320 SCSI 1-7
Version 2.4 Copyright © 2001–2004 by LSI Logic Corporation. All rights reserved.
1.4 Benefits of Ultra320 SCSI
Ultra320 SCSI is an extension of the SPI-4 draft specification that allows
faster synchronous SCSI data transfer rates than Ultra160 SCSI. When
enabled, Ultra320 SCSI performs 160 megatransfers per second,
resulting in approximately double the synchronous data transfer rates of
Ultra160 SCSI. The LSI53C1020 performs 16-bit, Ultra320 SCSI
synchronous data transfers as fast as 320 Mbytes/s. This advantage is
most noticeable in heavily loaded systems or large block size
applications, such as video on-demand and image processing.
Ultra320 SCSI doubles both the data and clock frequencies from
Ultra160 SCSI. Due to the increased data and clock speeds,
Ultra320 SCSI introduces skew compensation and ISI compensation.
These new features simplify system design by resolving timing issues at
the chip level. Skew compensation adjusts for timing differences between
data and clock signals caused by cabling, board traces, and so on. ISI
compensation enhances the first pulse after a change in state to ensure
data integrity.
Ultra320 SCSI includes CRC, which offers higher levels of data reliability
by ensuring complete integrity of transferred data. CRC is a 32-bit
scheme, referred to as CRC-32. CRC guarantees detection of all single
or double bit errors, as well as any combination of bit errors within a
single 32-bit range.
1.5 Benefits of SureLINK (Ultra320 SCSI Domain Validation)
SureLINK Domain Validation software ensures robust SCSI interconnect
management and low-risk Ultra320 SCSI implementations by extending
the domain validation guidelines documented in the SPI-4 specifications.
Domain validation verifies that the system is capable of transferring data
at Ultra320 SCSI speeds, allowing the LSI53C1020 to renegotiate to a
lower data transfer speed and bus width if necessary. SureLINK Domain
Validation is the software control for the domain validation manageability
enhancements in the LSI53C1020. SureLINK Domain Validation software
provides domain validation management at boot time as well as during
system operation.