Planning For Serial-Attached Scsi Cables - IBM 8202-E4B Manual

Different types of power cord retention are available. Some of the most commonly used types of retention
include:
v Cable management arms
v Rings
v Clamps
v Plastic straps
v Hook-and-loop fasteners
Power cord retainers are typically found at the rear of the unit and on the chassis or pedestal near the
alternating current (AC) power cord input.
Systems that are rack mounted and are on rails should use the provided cable management arm.
Systems that are rack mounted, but are not on rails should use the provided rings, clamps, or straps.
Figure 137. Cable management bracket

Planning for serial-attached SCSI cables

Serial-attached SCSI (SAS) cables provide serial communication for transfer of data for directly attached
devices, such as hard disk drives, solid-state drives, and CD-ROM drives.
SAS cable overview
Serial-attached SCSI (SAS) is an evolution of the parallel SCSI device interface into a serial point-to-point
interface. SAS physical links are a set of four wires used as two differential signal pairs. One differential
signal transmits in one direction while the other differential signal transmits in the opposite direction.
Data might be transmitted in both directions simultaneously. SAS physical links are contained in ports. A
port contains one or more SAS physical links. A port is a wide port if there are more than one SAS
physical link in the port. Wide ports are designed to enhance performance and provide redundancy
incase an individual SAS physical link fail.
There are two types of SAS connectors, mini SAS and mini SAS high density (HD). High density cables
are typically needed to support 6 Gb/s SAS.
Each SAS cable contains four SAS physical links that are typically organized into either a single 4x SAS
port or two 2x SAS ports. Each end of the cable uses a mini SAS or mini SAS HD 4x connector. Review
the following design and installation criteria before installing your SAS cables:
v Only specific cabling configurations are supported. Many configurations could be constructed that are
not supported and will either not function correctly or will generate errors. See "SAS cabling
configurations" on page 155 for figures of the supported cabling configurations.
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Planning for cables