Compaq StorageWorks UltraSCSI RAID Enclosure (DS-BA370 Series) User's Guide (EK-BA370-UG. C02, September 1998)

Single-Ended I/O Module
UltraSCSI RAID Enclosure 5–5
Controlling the Fault Bus
The I/O module controls fault bus operation in the following manner:
• Provides a fault bus driver for improved signal transmission
• Distributes the FAULT_CLK and FAULT_DATA signals from the
master enclosure to the expansion enclosures
• Distributes the SHELF_OK and SWAP_L signals from the
expansion enclosures to the master enclosure
Error Reporting
The EMU monitors the status of the I/O modules for the following
error conditions:
• Installation of incompatible I/O modules
• TERMPOWER problems
Incompatible I/O Modules
An I/O module error condition exists if any of the following
conditions exist:
• One or more nonoperating I/O modules
• Installation of fewer than six operational I/O modules
• All I/O modules are not the same type
When the EMU detects an I/O module error condition, it
automatically reports the problem to the array controller. Any
operational controller will automatically turn O
FF without
implementing procedures to clear the cache module. The result is that
the controller will cease to operate and be in an error state, a state that
can adversely affect the integrity of the data.
Note
Existance of an I/O module error condition prevents the
subsystem from operating.