 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] H. THOMPSON        ]    PASS PROGRAM NOTE        ]        102936    ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  10/10/88  ]
 ] LSIS/282-7225      ]      RELEASE NOTE( )        ] REV B: 09/29/95  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ]   OI-8C AND SUBS              ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW (X)  GNC ( )  VU ( )  SM/PL ( )] OP0,G1,G2,G3,S2,S4,G8,G9,P9     ]
 ]                                   ]                                 ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA:  I/O                                             ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS:  SDPS                                          ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ]         MMU I/O ERRORS LOGGED FOR OVERLAY REQUEST                   ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ]    WHENEVER A REQUEST FOR MMU OVERLAY IS RECEIVED BY FCOS, FCOS     ]
 ]    WILL PERFORM TWO MMU READ TRANSACTIONS PER PHASE:  A MM BITE     ]
 ]    STATUS READ (ASSOCIATED WITH THE POSITION TAPE COMMAND), AND     ]
 ]    AN OVERLAY READ.  BOTH OF THESE TRANSACTIONS WILL BE PERFORMED   ]
 ]    BY FCOS BEFORE A RETRY IS ATTEMPTED IN THE EVENT OF A MMU TRANS- ]
 ]    ACTION FAILURE.  IT IS POSSIBLE THAT ONE OR BOTH OF THESE MMU    ]
 ]    READ TRANSACTIONS FOR EACH OVERLAY PHASE WILL CREATE AN ENTRY    ]
 ]    IN THE I/O ERROR LOG, AND THERE MAY BE UP TO FOUR I/O ERRORS     ]
 ]    LOGGED AGAINST A PARTICULAR MMU BEFORE THE ALTERNATE MMU IS      ]
 ]    TRIED.                                                           ]
 ]                                                                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]                                                                     ]
 ]    ONE SHOULD BE AWARE THAT, DEPENDING ON THE TYPE OF MMU FAILURE,  ]
 ]    THERE MAY BE ANYWHERE FROM TWO TO FOUR MMU I/O ERRORS LOGGED     ]
 ]    BEFORE THE SWITCH TO THE ALTERNATE MMU IS ATTEMPTED.             ]
 ]                                                                     ]
 ]    IF AN ERROR IS DETECTED ON THE BITE STATUS READ DURING THE MMU   ]
 ]    PRE-POSITION TRANSACTION, THERE WILL BE ONE ADDITIONAL I/O       ]
 ]    ERROR LOGGED.                                                    ]
 ]                                                                     ]
 ]    ALSO REFER TO USER NOTES DRS 28364 AND 33268.                    ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]LSIS:  HUGH D. STOVALL    DATE 11/21/95]                             ]
 ]     -------------------      ---------]                             ]
 ]ASD:   ERIC C. BINGHAM    DATE 11/21/95]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 12/01/95 ]
 ]PF MGR: KAYLENE F. KINDT  DATE 11/30/95]------------------- -------- ]
 ]       ------------------     ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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