4-8 Operation DOC D00 025-A
4.6 Switching over to Dual-AMU
On switching over the passive AMU becomes the active AM U and if pos-
sible, the active AMU becomes the passive AMU. The connections of the
connection cables between AMU computer and control unit must be
changed over for the change.

Prerequisites

• 2 AMU computers are installed and in operation
• Both AMU computers are configured identically

Procedure

Step 1 Stop the command stream to the system:
• with the “HOLD” command for HACC/MVS
• by “Setting offline” the drives in the system
Step 2 Sw itch the AML/J off (Stopping the AML/ J system on page 4-4).
Step 3 C hange over the conn e c ti ons of the followin g cables at the con-
trol rack:
• Scanner interface cable X17 (COM 2)
• Ribbon cables XJ11, XJ5 and XJ3
Step 4 C lose the side d oor of the co ntrol cabinet
Step 5 S w itch the AM U (B) comp ute r on
Step 6 O pe n the AM U log in the menu with the command
Step 7 Switch the main switch S3 on the control rack on
Step 8 Switch the host to the Dual-AMU with the corresponding host
command
Figure 4-3: Plug bo ard of the AML/J co ntrol rack
XJ11 XJ3
XJ5
X17