IBM RS6000 - 7026 - H70 Service Manual

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

The SSA links must be configured as loops. The loop is connected to the internalconnectors at the SSA adapter card. These connectorsmust be a valid pair (that is,A1 and A2, or B1 and B2); otherwise, the disk drive modules on the loop are not fullyconfigured, and the diagnostics fail. Operations to all the disk drive modules on aparticular loop can continue if that loop breaks at any one point.Each pair of connectors has a green light that indicates the operational status of itsrelated loop:Disk Drive Module StringsIn the system unit, the disk drive modules are arranged in a string of 2 to 6 disk drivemodules. This string has its own two SSA connectors. This string is connectedthrough an internal SSA cable to a pair of connectors on the SSA adapter to makean SSA loop. (The SSA cables provide the SSA links.)Figure 3-2 shows the relationships between the SSA connectors and the disk drivemodule string in a system unit.Figure 3-2. A String of Disk Drive ModulesStatus of Light MeaningOff Both SSA connectors are inactive. If disk drive modules are connected tothese connectors, either those modules are failing, or their SSA links have notbeen enabled.Permanently on Both SSA links are active (normal operating condition).Slow Flash Only one SSA link is active.3-60 Service Guide