IBM 7133 D40, Service Manual

Page: 67 / 306

Larger Configurations
Four more disk drive modules can be added to the base configuration in one loop. For
a balanced subsystem, however, it is recommended that the two groups of disk drive
modules be connected in two separate loops, each of which is connected to a separate
pair of connectors on the SSA attachment (see Figure 28).
No improvement in performance is gained if the disk drive modules are moved to other
slots and connected in more than two loops by way of an additional SSA attachment.
The cables are described in “SSA Cables for 7133 Models D40 and T40” on page 56.
The internal connections of the 7133 are shown in “Internal Connections (Model D40)”
on page 28 and “Internal Connections (Model T40)” on page 30.
For information about the rules for SSA loops, see the “Rules for SSA Loops” on
page 47.
1
2 2 2
2
7133 unit
4
5
8
9
1
16
12
13
4 3 2 1
Using system
A1 A2 B1 B2
5 6 7 8
Figure 28. Larger Configuration
Chapter 1. Reference Information
49