Avago Technologies MegaRAID SAS 8204ELP - Manual (Page 81)

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peripheral
devices A piece of hardware (such as a video monitor, disk drive, printer, or
CD-ROM) used with a computer and under the control of the computer.
SCSI peripherals are controlled through a SAS MegaRAID SAS RAID
Controller (host adapter).
PHY The interface required to transmit and receive data packets transferred
across the serial bus.
Each PHY can form one side of the physical link in a connection with a
PHY on a different SATA device. The physical link contains four wires that
form two differential signal pairs. One differential pair transmits signals,
while the other differential pair receives signals. Both differential pairs
operate simultaneously and allow concurrent data transmission in both
the receive and the transmit directions.
RAID Acronym for Redundant Array of Independent Disks (originally
Redundant Array of Inexpensive Disks). An array of multiple independent
physical disks managed together to yield higher reliability, performance,
or both, exceeding that of a single physical disk. The RAID array appears
to the controller as a single storage unit. I/O is expedited because several
disks can be accessed simultaneously. Redundant RAID levels (RAID
levels 1, 5, 10, and 50) provide data protection.
RAID levels A set of techniques applied to disk groups to deliver higher data
availability, and/or performance characteristics to host environments.
Each virtual disk must have a RAID level assigned to it.
SAS Acronym for Serial Attached SCSI. A serial, point-to-point,
enterprise-level device interface that leverages the proven SCSI protocol
set. The SAS interface provides improved performance, simplified
cabling, smaller connections, lower pin count, and lower power
requirements when compared to parallel SCSI. SAS controllers leverage
a common electrical and physical connection interface that is compatible
with Serial ATA. The SAS controllers support the ANSI Serial Attached
SCSI Standard, Version 1.0. In addition, the controller supports the
Serial ATA II (SATA II) protocol defined by the Serial ATA Specification,
Version 1.0a. Supporting both the SAS and SATA II interfaces, the SAS
controller is a versatile controller that provides the backbone of both
server and high-end workstation environments. Each port on the SAS
RAID controller supports SAS devices, SATA II devices, or both.