IBM 7133 D40, Руководство по обслуживанию

Страница: 61 / 306

If power is switched off to adapter 2, the loop is broken. The 7133 bypass card detects
the loss of voltage, goes into bypass state, and reconnects the loop. Adapter 2 is
bypassed as shown in Figure 24.
Forced Inline Mode
When a bypass card is set to operate in Forced Inline mode, its Mode light is green,
and its two Link Status (Ready) lights are off.
Forced Inline mode is used to disable the switching ability of selected bypass cards in
particular types of subsystem configuration. The types of configuration that might
require Forced Inline mode are those in which:
v
Two 7133s are connected to each other. In this type of configuration, Forced Inline
mode removes the risk that a fault condition might break the connection between the
two 7133s. The second example in “Higher-Availability Configurations” on page 54
shows a typical configuration of this type.
v
The disk drive modules in one 7133 are not all connected to the same SSA loop. In
this type of configuration, Forced Inline mode removes the risk that a fault condition
might cause the disk drive modules of different loops to be connected to each other.
Adapter 1 Adapter 2
Disk
16
Disk
15
Disk
14
Disk
13
Disk
12
Disk
11
Disk
10
Disk
9
16 4 5 9 8 1 13 12
Disk
1
Disk
2
Disk
3
Disk
4
Disk
5
Disk
6
Disk
7
Disk
8
A B A B
Figure 24. Automatic Mode: No Power at Adapter 2
Chapter 1. Reference Information
43