 +_____________________________________________________________________
  AUTHOR:                                          DR:              
  DEBORAH MCCLEAN        PASS PROGRAM NOTE               107443     
 ____________________                             __________________
  ORG/PHONE:          OPS NOTE (X)  USER NOTE ( )  DATE:            
  LSIS/282-7465            RELEASE NOTE( )               08/15/94   
 ___________________________________________________________________
  OI/FLIGHT EFFECTIVITY:          USER AFFECTED:                     
  OI-21 THRU OI-24                CREW (X)  GROUND (X)  DUMP ONLY ( )
 ____________________________________________________________________
         MAJOR SOFTWARE AREA:        OPS MODES AFFECTED:             
 SSW (X)  GNC ( )  VU ( )  SM/PL ( ) ALL                             
 _____________________________________________________________________
  SOFTWARE SUB-AREA: ANNUNCIATION                                     
 _____________________________________________________________________
  PRINCIPAL FUNCTIONS: SANU                                           
 _____________________________________________________________________
  TITLE:                                                              
  GPC FAILURE CONDITIONS CAN CAUSE EXTRANEOUS ANNUNCIATIONS           
 _____________________________________________________________________
  DESCRIPTION:                                                        
                                                                      
  IF A FAILURE CONDITION OCCURS THAT RESULTS IN BITS BEING SET IN A   
  SPECIFIC FULLWORD OF THE ANNUNCIATION BUFFER                        
  (CANB_ANN_MSG_BITS(7;59 TO 60)) WHEN THOSE BITS DO NOT CORRESPOND   
  TO ANY VALIDLY DEFINED ANNUNCIATION MESSAGES, THE SOFTWARE WILL     
  INCORRECTLY PROPAGATE THOSE BITS INTO ALL OTHER PRECEDING FULLWORDS 
  OF THE ANNUNCIATION BUFFER, RESULTING IN THE CONTINUOUS ANNUNCIATION
  OF ANY VALID ANNUNCIATION MESSAGES THAT THOSE BITS CORRESPOND TO.   
  THE SOFTWARE NEVER INTENTIONALLY SETS INVALID ANNUNCIATION BITS;    
  THEREFORE, IN ORDER TO ENCOUNTER THIS CONDITION, A FAILURE OF SOME  
  TYPE MUST OCCUR WHICH AFFECTS THE GPC PROCESSING RELATED TO SETTING 
  OF ANNUNCIATION BITS IN THIS PARTICULAR FULLWORD OF THE ANNUNCIA-   
  TION BUFFER.  THE EFFECTS OF THIS PROBLEM WILL BE LIMITED TO THE    
  GPC EXPERIENCING THE FAILURE EXCEPT IN THE FOLLOWING SCENARIO.      
                                                                      
     1) PASS MUST BE EXECUTING IN GPC 5                               
 AND 2) GPC 5 MUST EXPERIENCE A FAILURE WHICH CAUSES IT TO REQUEST    
        ANNUNCIATION OF AN INVALID ANNUNCIATION MESSAGE CORRESPONDING 
        TO A BIT IN THE SPECIFIED FULLWORD OF THE ANNUNCIATION BUFFER 
 AND 3) GPC 5 MUST REMAIN HEALTHY ENOUGH AFTER THAT FAILURE TO REMAIN 
        IN THE PASS COMMON SET UNTIL THAT ERRONEOUS ANNUNCIATION      
        REQUEST CAN BE SUCCESSFULLY ICC'ED TO OTHER PASS COMMON SET   
        MEMBERS.                                                      
                                                                      
  IF THE ABOVE SCENARIO OCCURS, THE RESULTANT ERRONEOUS ANNUNCIATIONS 
  WILL AFFECT ALL PASS COMMON SET GPCS.                               
 _____________________________________________________________________
 CONCURRENCE:                           APPROVAL:                    
 LSIS:  HUGH D. STOVALL    DATE 09/28/94                             
      -------------------      ---------                             
 ASD:    W. R. PRUETT      DATE 10/05/94                             
      -------------------      --------- DARRELL E. STAMPER 10/05/94 
 PF MGR: KAYLENE F. KINDT  DATE 09/30/94------------------- -------- 
        -----------------      --------- CHAIRMAN, SASCB      DATE   
 ____________________________________________________________________
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 +_____________________________________________________________________
                                                                      
                        SUPPLEMENTAL SHEET                            
                                                                      
 _____________________________________________________________________
  AUTHOR:                                          DR:              
  DEBORAH MCCLEAN        PASS PROGRAM NOTE               107443     
 ____________________                             __________________
  ORG/PHONE:          OPS NOTE (X)  USER NOTE ( )  DATE:            
  LSIS/282-7465            RELEASE NOTE( )               08/15/94   
 ___________________________________________________________________
  TITLE:                                                              
    GPC FAILURE CONDITIONS CAN CAUSE EXTRANEOUS ANNUNCIATIONS         
                                                                      
 _____________________________________________________________________
 USER RESPONSE:                                                       
                                                                      
 IF CONTINUOUS EXTRANEOUS ANNUNCIATION MESSAGES OCCUR, IT CAN BE      
 VERIFIED THAT THE SOURCE OF THOSE MESSAGES IS ERRONEOUS BIT SETTINGS 
 IN THE ANNUNCIATION BUFFER BY VIEWING THE SPECIFIED FULLWORD USING   
 SPEC 0.                                                              
                                                                      
 IF THE PROBLEM OCCURS IN A SINGLE GPC, NORMAL PROCEDURES FOR A GPC   
 WHICH HAS EXPERIENCED A HARDWARE PROBLEM SHOULD BE FOLLOWED.         
                                                                      
 BE AWARE THAT, IF THE PASS IS TO BE EXECUTED IN GPC 5, THE POSSIB-   
 ILITY EXISTS THAT THIS PROBLEM COULD AFFECT ALL PASS COMMON SET GPCS 
 IF A SPECIFIC FAILURE CONDITION OCCURS IN GPC 5.  IN ORDER TO CLEAR  
 THE CONDITION IF IT OCCURS, A RE-IPL OF ALL PASS COMMON SET GPCS     
 WOULD BE REQUIRED.  SINCE THE ANNUNCIATION BUFFER RESIDES IN THE SSW 
 BASE (AND NOT IN MAJOR FUNCTION BASE OR PROGRAM OVERLAY SPECIFIC     
 SOFTWARE) THIS CAN BE ACCOMPLISHED BY RE-IPL'ING EACH GPC IN TURN    
 AND THEN REINCLUDING IT INTO THE SET VIA GPC-TO-GPC OVERLAY IF       
 IT IS DESIRABLE TO AVOID RE-UPLINK OF MAJOR FUNCTION BASE OR         
 PROGRAM OVERLAY SPECIFIC DATA.                                       
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
                                                                      
 _____________________________________________________________________
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