General Description 1-5
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These SAS controllers are based on the LSISAS2108 RAID On-a-Chip
(ROC) device or the LSISAS2008 PCI Express-SAS/SATA I/O Processor
chip. These devices are compliant with the Fusion-MPT™ architecture
and provides a PCI Express x8 interface.
Note: All of these RAID controllers provide an x8 PCI Express 2.0
interface.
The LSISAS2108 ROC device provides an eight-lane, 5-Gb/s PCI
Express host interface, eight 6.0 Gb/s SAS ports or eight 3.0 Gb/s SATA
ports, and a full-featured, hardware-based RAID implementation. In
addition, it integrates a high-speed DDR/DDR2 800 MHz SDRAM
interface with a hardware RAID assist engine for parity calculations. The
LSISAS2108 ROC device provides the maximum benefits of a RAID
system and enables you to configure the system to satisfy your system
requirements.
The LSISAS2108 ROC device increases system performance and
provides fault-tolerant data storage. The LSISAS2108 supports data
striping across multiple drives, which reduces drive access time because
multiple drives simultaneously read or write data. The LSISAS2108 ROC
device backs up data with either data mirroring or a parity block. Either
backup method enables you to recover lost data in the event of a drive
failure. You can select the data backup method that best suits your
needs. A hardware RAID assist exclusive-OR (XOR) engine speeds
parity generation and checking and reduces system-access times.
The SAS RAID controllers integrate eight high-performance SAS/SATA II
PHYs and a PCI Express bus master DMA core. Each of the eight PHYs
is capable of 6.0 Gb/s SAS link rates and 3.0 Gb/s SATA II link rates.
These devices adhere to the PCI Express Specification, Revision 2.0.
The PCI Express software is backward compatible with previous
revisions of the PCI bus and PCI-X bus.
The SAS RAID controllers support the SAS protocol as described in the
Serial Attached SCSI Standard, version 2.0. The controllers also support
the Serial ATA II (SATA II) protocol defined by the Serial ATA
Specification, Version 1.0a and the Serial ATAII; Extension to the Serial
ATA Specification, Version 1.1. SATA II is an extension to SATA 1.0a.
In addition, the SAS RAID controllers support the following SATA II
features: