IBM RS/6000 7025 F50 Series, Service Manual, Page: 158 / 362

Example 2. Broken Loop (Cable Removed):
Each disk drive module normally
communicates with the adapter through one data path. Because data can pass
around the loop in either direction, however, the adapter automatically reconfigures
the loop to enable communication to continue to each disk drive if the loop becomes
broken.
In Figure 3-6, eight disk drive modules should be connected to connectors A1 and
A2 of the SSA adapter. However, the loop is broken because the SSA cable has
been disconnected from connector A2. Four disk drive modules are connected to
connectors B1 and B2 of the same SSA adapter.
Although the broken loop is reported as an error, all the disk drive modules can still
communicate with the using system. The eight disk drive modules can communicate
through connector A1 of the SSA adapter . The five disk drive modules can
communicate through connectors B1 and B2 of the same SSA adapter (normal loop).
Figure 3-6. Broken Loop
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