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1 Controller Overview
This chapter provides an overview of the SAS controller and its technology. This chapter includes
the following topics:
"Serial-Attached SCSI (SAS) Technology Description" (page 9)
"Controller Description" (page 9)
Serial-Attached SCSI (SAS) Technology Description
Serial-attached SCSI (SAS) is a method for connecting computer peripheral devices that employs
a serial (one bit at a time) means of digital data transfer over thin cables. The method is specified
in the American National Standard Institute standard called Serial-attached SCSI (Small Computer
System Interface), also known as ANSI/INCITS 376-2003. In enterprise computing, SAS is of
particular interest for access to mass storage devices, particularly hard disks.
Serial-attached SCSI offers the following advantages over older parallel SCSI technologies:
•
The cables are thinner, and the connectors are less bulky.
•
Serial data transfer allows the use of longer cables than parallel data transfer.
•
Problems related to crosstalk are less likely in serial interfaces than in parallel interfaces,
because there are fewer conductors in the cables.
•
The hardware for serial interfaces is less costly than the hardware for equivalent parallel
interfaces.
SAS offers data transfer rates in excess of 3 gigabits per second (Gb/s), with potential rates of 10
Gb/s or more. Serial-attached SCSI provides an ideal solution for businesses with substantial
storage, backup, and archiving demands.
Controller Description
There are two internal SAS controller form factors, depending on the server model:
•
HP 8 Internal Port SAS Controller, a low-profile, 64-bit, 133-MHz PCI-X host bus adapter
which is available only as a factory-integrated core I/O option in certain servers.
•
HP Multi-Port Internal SAS Controller, an embedded controller on the server motherboard.
Both controllers are supported by the SerialSCSI-00 operating system driver bundle, and by
utilities delivered in the CommonIO bundle.
Both controllers have the same key features:
•
SAS data transfer rates of up to 3 Gb/s
•
Data protection through Integrated Mirror (RAID 1)
Serial-Attached SCSI (SAS) Technology Description
9
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