 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ]  PAUL TICE         ]    PASS PROGRAM NOTE        ]       55355      ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE:  12/04/85  ]
 ]  LSIS/282-7297     ]      RELEASE NOTE( )        ] REV A: 01/29/96  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ]  OI-07 AND SUBS               ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW (X)  GNC ( )  VU ( )  SM/PL ( )] 0, G1, G2, G3, G6, G8, G9, S2,  ]
 ]                                   ] S4, PL9                         ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: DOWNLIST, CYCLE-WRAP                             ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: SDLT                                           ]
 ]_____________________________________________________________________]
 ] TITLE:        DOWNLIST I/O CYCLE WRAPS AFTER MTU UPDATES            ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] ONE-TIME SVC INITIATED DOWNLIST I/O'S ARE USED TO ESTABLISH PSEUDO- ]
 ] SYNC AT: 1) THE BEGINNING AND END OF AN OPS/MODE RECALL WITH A      ]
 ] TARGET SET CHANGE OR OPS TRANSITION AND 2) SECONDARY GPC INITIALI-  ]
 ] ZATION WHEN A NEW GPC IS JOINING THE COMMON SET.  THE INITIAL       ]
 ] PHASING OF THESE ONE-TIME DOWNLIST I/O'S IS 24 MILLISECONDS BEFORE  ]
 ] THE 25 HZ TIMER INITIATED CYCLIC DOWNLIST I/O'S.  CUMULATIVE GMT    ]
 ] UPDATES OF APPROXIMATELY 19 TO 24 MSEC OR -16 TO -21 MSEC AND       ]
 ] INCREMENTS OF 40 MSEC EITHER WAY (E.G. 59 TO 64, -56 TO -61, ETC.), ]
 ] CAUSE THE ONE-TIME SVC INITIATED DOWNLIST I/O TO BE MOVED CLOSE     ]
 ] ENOUGH TO THE CYCLIC TIMER INITIATED DOWNLIST I/O SUCH THAT THE PMU ]
 ] BUS IS NOT FREED UP IN TIME TO START THE TIMER INITIATED I/O.  THIS ]
 ] RESULTS IN A DOWNLIST I/O CYCLE WRAP GPC ERROR (GROUP 7 CODE 5).    ]
 ] THESE GPC ERRORS WILL CONTINUE TO OCCUR, AS LONG AS THE CUMULATIVE  ]
 ] GMT UPDATES FALL IN ONE OF THE AFOREMENTIONED RANGES, AS FOLLOWS:   ]
 ] - 2 LOGGED BY ALL GPCS COMPLETING AN OPS/MODE RECALL WITH A TARGET  ]
 ]   SET CHANGE OR OPS TRANSITION                                      ]
 ] - 1 LOGGED BY ANY GPC DROPPED DURING AN OPS/MODE RECALL OR OPS      ]
 ]   TRANSITION (DUE TO TARGET SET CHANGE OR I/O ERRORS)               ]
 ] - 1 LOGGED BY A GPC ADDED TO THE CS (PREVIOUSLY LOADED OR IPL'ED)   ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ]                                                                     ]
 ] BE AWARE THAT THIS PROBLEM EXISTS AND, IF THESE GPC ERRORS AND LOSS ]
 ] OF PSEUDO SYNC ARE NOT DESIRED, DO NOT PERFORM CUMULATIVE GMT       ]
 ] UPDATES THAT FALL IN THE AFOREMENTIONED RANGES WITHOUT SUBSEQUENTLY ]
 ] GOING THROUGH PRIMARY GPC INITIALIZATION (REFORMING THE GPC SET).   ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]LSIS:   JEAN L. ZOPHY     DATE 03/19/96]                             ]
 ]     -------------------      ---------]                             ]
 ]ASD:   ERIC C. BINGHAM    DATE 03/20/96]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 03/22/96 ]
 ]PF MGR: KAYLENE F. KINDT  DATE 03/20/96]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_______________________________________]_____________________________]
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