 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] SMS: B28618      ]
 ]    S. VENITSKY     ]    BFS PROGRAM NOTE         ] DR:  106203      ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:  RID    ] OPS NOTE ( )  USER NOTE (X) ] DATE:  05/14/91  ]
 ]  (310) 922-1921    ]      RELEASE NOTE ( )       ]REV A:  09/06/94  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] OI-8F AND SUBS                ]  CREW ( )  GROUND (X)  DUMP ONLY ( )]
 ]_______________________________]_____________________________________]
 ]           MAJOR SOFTWARE AREA:            ] OPS MODES AFFECTED:     ]
 ]BSL( ) BSS(X) GNC( ) SEQ( ) SM/SP( ) IPL( )]      0, 1, 3, 6         ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA:  DOWNLIST                                        ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: MG038101/3.7.2.2                               ]
 ]_____________________________________________________________________]
 ] TITLE: BFS SOFT ERROR COUNTER (SEC)                                 ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ]                                                                     ]
 ] BFS DOES NOT ACCURATELY LOG SEC ERRORS ON THE DOWNLIST.  THIS IS    ]
 ] NOT A SERIOUS PROBLEM BECAUSE THE OCCURRENCE OF MEMORY ERRORS CAN   ]
 ] STILL BE DETERMINED BY THE FOLLOWING SEC SIGNATURES:                ]
 ] (1) SOFT SINGLE BIT ERRORS - WILL BE CORRECTED AND SEC WILL MOST    ]
 ]     LIKELY BE ZERO.                                                 ]
 ] (2) MULTIPLE BIT ERRORS - WILL NOT BE CORRECTED AND SEC WILL        ]
 ]     CONTAIN VALUES OF '1' OR GREATER AT THE APPROXIMATE RATE OF     ]
 ]     ONCE/MINUTE.  ONE OBSERVANCE OF A SMALL ('1' OR '2') NON-ZERO   ]
 ]     VALUE IS MOST LIKELY A MULTIPLE BIT ERROR.  TWO OR MORE         ]
 ]     OBSERVANCES ON THE ORDER OF ONCE/MINUTE APART IS ALMOST         ]
 ]     DEFINITELY A MULTIPLE BIT ERROR.  IF AFFECTED MEMORY LOCATION   ]
 ]     IS ACCESSED, EITHER GPC BITE ERROR WILL OCCUR OR BFS WILL BE IN ]
 ]     A CONTINUOUS RESTART. IF AFFECTED MEMORY LOCATION IS IN LOWER   ]
 ]     MEMORY, THEN CONTINUOUS GPC ERRORS MAY BE LOGGED DEPENDING ON   ]
 ]     FREQUENCY OF DATA/CODE ACCESS.                                  ]
 ] (3) SINGLE BIT HARDWARE MEMORY FAULT - THIS CASE IS DIFFICULT TO    ]
 ]     DISTINGUISH FROM (2).  THIS IS A HARDWARE FAILURE OF A SINGLE   ]
 ]     BIT IN MEMORY.  THE VALUE WILL BE CORRECT WHEN USED.  EXCEPT    ]
 ]     FOR GPC BITE ERROR OR BFS RESTART, THE SIGNATURE WILL BE THE    ]
 ]     SAME AS (2).                                                    ]
 ] (4) HARDWARE (CHIP) FAILURE - FOR EACH DOWNLIST CYCLE, THE SEC WILL ]
 ]     APPEAR TO HAVE AN APPARENTLY RANDOM VALUE BETWEEN ZERO - '7F'.  ]
 ]     '7F' IS THE MAXIMUM VALUE FOR THE SEC.                          ]
 ]_____________________________________________________________________]
 ] USER RESPONSE:                                                      ]
 ] (1) NONE.                                                           ]
 ] (2) THE GPC IS SUSPECT. IN OPS 0 AND PRE-DEORBIT BURN OPS 3, MOVE   ]
 ]     BFS TO ANOTHER SLOT. OTHERWISE, BFS SHOULD BE DECLARED NO-GO.   ]
 ] (3) USE THE RESPONSE OF (2) ABOVE.                                  ]
 ] (4) THE GPC IS FAILED. USE THE RESPONSE OF (2) ABOVE.               ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]RI: <S> G. ALBRIGHT       DATE 09/06/94]                             ]
 ]    --------------------      ---------]                             ]
 ]ASD:    W. R. PRUETT      DATE 10/05/94]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 10/05/94 ]
 ]PF MGR:DAVID STEPHENSON   DATE 10/04/94]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_____________________________________________________________________]
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