 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ]  M. SOMERS         ]    PASS PROGRAM NOTE        ]      103827      ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  10/12/89  ]
 ] IBM/ASD/282-7324   ]      RELEASE NOTE( )        ] REV A: 11/07/89  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI8B AND SUBS                 ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW (X)  GNC ( )  VU ( )  SM/PL ( )]     G9                          ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA:  TRANSITIONS, I/O                                ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS:  SACH, SBIO                                    ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ]        I/O ERROR WHEN RS GPC MODED TO STBY                          ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] UPON MODING TO STANDBY A REDUNDANT SET GPC THAT IS STILL IN COMMAND ]
 ] OF ACTIVE REDUNDANT SET BUSES, THERE EXISTS THE POTENTIAL THAT THE  ]
 ] REMAINING REDUNDANT SET GPCS WILL EXPERIENCE AN I/O ERROR ON A BUS  ]
 ] OTHER THAN AN IC BUS.  PARTICULAR SIGNATURES ARE SCENARIO DEPENDENT ]
 ] (E.G. WHETHER FC, PL, LB, MM, OR DK BUSES ARE INVOLVED, WHETHER OR  ]
 ] NOT THE ERROR IS UNIVERSALLY DETECTED, OR WHAT TYPE OF I/O ERROR IS ]
 ] ENCOUNTERED.)                                                       ]
 ]                                                                     ]
 ] THE PASS WILL NOT USE THE DATA, AND THE I/O BUFFER MAY CONTAIN BAD  ]
 ] DATA.  IN ANY CASE IT WILL BE A ONE TIME ERROR, AND THE DATA WILL   ]
 ] BE COMMFAULTED OR ERROR STATUS RETURNED WHERE APPROPRIATE.          ]
 ]                                                                     ]
 ] THE GPC IS IMMEDIATELY REMOVED FROM THE REDUNDANT SET.              ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]                                                                     ]
 ]  EXPOSURE TO THIS G9 RS ANOMALY CAN BE ELIMINATED:                  ]
 ]                                                                     ]
 ]  1. BY INHIBITING HDA (SPEC 100, ITEM 2) AND ENSURING THAT          ]
 ]     USER INITIATED I/O (E.G. SPEC, TCS/SACS, ECP) IS NOT ACTIVE     ]
 ]                                                                     ]
 ]  OR                                                                 ]
 ]                                                                     ]
 ]  2. BY TAKING THE GPC TO OPS 0 PRIOR TO MODING TO STANDBY           ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]IBM: WYATT COOPER         DATE 11/15/89]                             ]
 ]    --------------------      ---------]                             ]
 ]SSD: W.R. PRUETT          DATE 11/15/89]                             ]
 ]    --------------------      ---------] M.C. GREMILLION    11/16/89 ]
 ]PF MGR:MICHAEL BRIEDEN    DATE 11/16/89]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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