Description The Trusted TMR expander processor module resides in the processor slots of the Trusted expander chassis and provides the slave interface between the expansion bus and the expander chassis backplane. The expander bus allows multiple chassis systems to be implemented using UTP cable connections whilst maintaining the fault tolerant, high bandwidth inter-module bus (IMB) capabilities. The module provides fault containment for the expander bus, the module itself and the expander chassis, ensuring that the effects of these potential faults are localized and system availability maximized. The module is fault tolerant with Hardware Implemented Fault Tolerant (HIFT), Triple Modular Redundant (TMR) architecture. Comprehensive diagnostics, monitoring and testing provide rapid fault identification. Hot standby and module sparing configurations are supported, allowing automatic and manual repair strategies. Communication between the expander processor and the TMR processor is via the TMR expander interface module and the triplicated expander bus. The expander bus is triplicated, point-to-point architecture. Each channel of the expander bus comprises separate command and response media. Voting is provided at the expander bus interface to ensure that cable faults are tolerated, and the remainder of the expander processor operates in a fully triplicated mode, even in case of cable faults occurring. Communication between the expander processor and the I/O modules in the expander chassis is via the IMB on the backplane of the expander chassis. The IMB is identical to that within the controller chassis, providing the same fault tolerant, high bandwidth communications between the interface modules and the TMR processor. As with the expander bus interface all transactions are voted, localizing faults to Fault Containment Region (FCR) within the IMB should occur. The TMR expander processor module derives its internal voltages from dual redundant +24V dc power supplied via the module connector from the Trusted expander chassis backplane. Each FCR derives the required supplies independently. Non-critical monitoring and module status display functions (front panel LEDs) are also provided. Features Triple Modular Redundant (TMR), fault tolerant (3-2-0) operation. Hardware Implemented Fault Tolerant (HIFT) architecture. Dedicated hardware and software test regimes which provide fast fault recognition and response times. Automatic fault handling without nuisance alarming. Hot replacement. Front panel status LEDs.
