IBM 7133 D40, Service Manual

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SSA Subsystem Configurations
The diagrams in this section show some sample configurations for the 7133. All the
configurations that are shown here are the simplest and provide the best ease of use.
If performance or availability are particularly important to the customer, however, more
complex cabling might provide a better solution; consult your marketing
representative for more details.
Under the standard SSA rules, you can mix any compatible SSA devices in a particular
SSA loop.
Rules for SSA Loops
Details of the rules for configuring SSA loops are given in the user or
maintenance information for your using-system SSA attachment hardware (see
Related Publications in the additional information appendix (in this book) for your
using system). SSA loops that include disk drives that are installed in a 7133 Model
D40 or Model T40 must also follow these additional rules:
v
A maximum of three dummy disk drive modules can be connected to each other in a
particular SSA loop.
v
The maximum permitted length for an external SSA cable that connects two SSA
nodes (for example, disk drives) is 25 meters (82 feet).
v
Under some conditions, the maximum permitted length for a fibre optic cable that
connects two SSA nodes (for example, disk drives) is:
– 3 kilometers (9842 feet) for multi-mode operations
– 10 kilometers (32800 feet) for single-mode operations
Otherwise, the maximum permitted length for single-mode and multi-mode operations
is 2.4 kilometers (7874 feet). See “Specifications for Fibre Optic Cables and
Connectors” on page 26 for details.
Cable Configurations
In the diagrams, the SSA connectors are numbered. These connector numbers match
those shown in “Internal Connections (Model D40)” on page 28 and “Internal
Connections (Model T40)” on page 30.
Chapter 1. Reference Information
47