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Improving the Reliability and Availability of Computer Systems by Self-Checking and Monitored Processor Interconnections

IP.com Disclosure Number: IPCOM000034759D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 96K

Publishing Venue

IBM

Related People

Doettling, G: AUTHOR [+4]

Abstract

For checking a cable connection, two wires are required in the cable and two pins in the cable connector. This approach is called pin coding. The pins are selected such that one is at the far left and the other at the far right of the connector. Connectors with a greater number of pins are used to increase the checking reliablity. This permits detecting even those connections that are almost loose. At cable receptacle A on the processor side (Fig. 1) where the connection is to be checked, one of the pins, say, pin 1, is connected to ground, whereas the other, say, pin 62, is linked by a terminator to the voltage level at which the processor is operated (3 kohm to 3.4 V or 3 kohm to 5 V (Fig. 1)). The pin which is connected to a voltage level by a terminator is made accessible for the processor.

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Improving the Reliability and Availability of Computer Systems by Self- Checking and Monitored Processor Interconnections

For checking a cable connection, two wires are required in the cable and two pins in the cable connector. This approach is called pin coding. The pins are selected such that one is at the far left and the other at the far right of the connector. Connectors with a greater number of pins are used to increase the checking reliablity. This permits detecting even those connections that are almost loose. At cable receptacle A on the processor side (Fig. 1) where the connection is to be checked, one of the pins, say, pin 1, is connected to ground, whereas the other, say, pin 62, is linked by a terminator to the voltage level at which the processor is operated (3 kohm to 3.4 V or 3 kohm to 5 V (Fig. 1)). The pin which is connected to a voltage level by a terminator is made accessible for the processor. This can be done by direct connection to the processor chip or to any processor support chip (such as the memory management unit, the system bus adapter, etc.) which is accessed by a read command. The cable plug provides a connection to a wire, called cable connection check wire, for the respective pins. At the other end where the cable plug is connected to cable receptacle B, a jumper is installed for the cable connection check pins, say, from pin 1 to pin 62 (Fig. 1). If the cable is properly connected at both ends, the pin

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that is connected to a voltage level by a terminator is pulled down to ground level by the pin that is connected to ground (cable - jumper - cable). When all cable connection check points are at ground level, the cables are installed properly. This check should be made after power-on or as part of the machine error detection routines. Another reliability requ...