IBM RS6000 - 7026 - H70 Service Manual

Also see for RS/6000 7025 F50 Series: User guide Service guide Service guide

Example 2. Broken Loop (Cable Removed): Each disk drive module normallycommunicates with the adapter through one data path. Because data can passaround the loop in either direction, however, the adapter automatically reconfiguresthe loop to enable communication to continue to each disk drive if the loop becomesbroken.In Figure 3-6, eight disk drive modules should be connected to connectors A1 andA2 of the SSA adapter. However, the loop is broken because the SSA cable hasbeen disconnected from connector A2. Four disk drive modules are connected toconnectors B1 and B2 of the same SSA adapter.Although the broken loop is reported as an error, all the disk drive modules can stillcommunicate with the using system. The eight disk drive modules can communicatethrough connector A1 of the SSA adapter . The five disk drive modules cancommunicate through connectors B1 and B2 of the same SSA adapter (normal loop).Figure 3-6. Broken Loop3-86 Service Guide