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  | d i g i t a l |    I n t e r o f f i c e   M e m o r a n d u m
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  Subj: Fast Memory Sweeps in KLERR


     This document describes the new KLERR feature that will  perform  a
     fast  memory  (FM)  sweep when a FM parity error is detected.  This
     feature will be in KLERR version 3 which  will  be  available  with
     RSX-20F V13-37.  It will go to the field with the TOPS-20 release 4
     third field test and TOPS-10 release 7.00 fifth field test.

     The FM sweep will be done only when KLERR runs and if a  FM  parity
     error  exists.   KLERR will run only when RSX-20F detects some sort
     of fatal error condition in the KL.  When KLERR  runs  it  executes
     several  function  reads  to  obtain the KL10 internal parity error
     flags, if the CLK FM PAR ERR H flag is set then a FM  parity  error
     exists.   At  this  point  a flag will be set so that after the 100
     function reads that KLERR executes the FM sweep will be performed.

     The FM sweep consists of examining all 16 AC's of each AC block and
     if  a  parity error occurs on the examine then a message is output.
     The specific operations involved in the sweep are:

          1. Disable parity error stops and clear clock error stop
          2. Put KL in halt loop
          3. Start KL clock
          4. Set AC block
          5. Read AC
          6. Read parity error flag and if error type message
          7. Repeat 5-6 for each AC in block
          8. Repeat 4-7 for each AC block
          9. Restore original AC block

     The FM sweep  output  consists  of  a  header  line  informing  the
     operator  that  a  FM parity error has been detected.  On this same
     line the block number, AC address, and AC contents of  the  current
     AC locked up in the FM address and output registers are typed.  Any
     errors detected in the sweep are  output  with  the  block  number,
     address and contents of the AC preceeded with a FM SWEEP -- prompt.

     The following is an example of output from KLERR when  a  FM  sweep
     occurs:



  KLERR -- VERSION V03-00 RUNNING

  DLYCNT: 000000
  DEXWD3: 060626

  DEXWD2: 000000
  DEXWD1: 000001
     KL10 DATA=040000,,060626
  TENAD1: 000000  TENAD2: 000007
     ADDRESS SPACE=EPT
     OPERATION=EXAMINE
     PROTECTION-RELOCATION IS ON
     KL10 ADDRESS=7
  TO10BC: 010000  TO11BC: 130000
  TO10AD: 066452  TO11AD: 066512
  TO10DT: 000000  TO11DT: 050000
  DIAG1 : 006400
     KL CLOCK ERROR STOP
     KL IN RUN MODE
     MAJOR STATE IS DEPOSIT-EXAMINE
  DIAG2 : 050000
  STATUS: 002100
     DEX WORD 1
     E BUFFER SELECT
  DIAG3 : 000000

  KLERR -- KL NOT IN HALT LOOP
  KLERR -- CLOCK ERROR STOP
  KLERR -- KL VMA: 000000 000441    PC: 000000 000253
  KLERR -- PI STATE: ON  , PI ON: 177 , PI HLD: 000 , PI GEN: 000
  KLERR -- FM PARITY ERROR-(BLOCK:ADDR/DATA) 1:5/ 252525,,252525
      FM SWEEP -- 1:12/ 252525,,252525
      FM SWEEP -- 1:11/ 252525,,252525
      FM SWEEP -- 1:5/ 252525,,252525
  KLERR -- EXIT FROM KLERR