PJ41068: POSSIBLE NORM STATE TIME CHANGE ISSUE - PJ40381

APAR status

• Closed as program error.

Error description

• See Problem Summary.
  

Local fix

• na
  

Problem summary

• APAR NUMBER:  PJ41068
  PRODUCT:  z/TPF
  FUNCTIONAL AREA:  CLOCKS
  SHIPPED IN PUT:
  
  ABSTRACT:
  Due to PJ40381, global fields @U1ZID (GMT last midnight),
  @GMTDA (GMT day number), and @GMTDY (GMT date) may not be
  correct.
  
  PACKAGE CONTENTS:
  Source Segments:
  (C) base/macro/gclkx.mac
  (C) base/rt/cdtc.asm
  (C) base/rt/glbl.asm
  
  Object Only Binaries:
  None.
  
  Configuration Independent Binaries:
  None.
  
  Support Files:
  None.
  
  OTHER BINARIES TO BUILD: YES
  (C) <sys>/load/CDTC.so
  (C) <sys>/load/GLBL.so
  (C) <sys>/obj/cdtc.o
  (C) <sys>/obj/glbl.o
  
  COMMENTS:
  First, PJ40381 was intended to change GMT last midnight global
  field @U1ZID and keypoint B field CK9ZID to be relative to
  perpetual minute global field @C0CLO and keypoint B field
  CK9CLO. PJ40381 did change keypoint B field CK9ZID to be
  relative to @C0CLO and CK9CLO. When daylight savings time is
  turned on or off, CK9ZID is adjusted using the daylight savings
  time offset. However, the changes in CK9ZID are not reflected
  in global field @U1ZID. Therefore, @U1ZID is not adjusted when
  daylight savings time is turned on or off.
  
  Second, when command ZATIM DST ON has turned on daylight
  savings time and the system is cycled to norm state and PJ40381
  is applied, global fields @GMTDA (GMT day number) and @GMTDY
  (GMT date) will be wrong. On cycle to norm program CDTC sets
  GMT global fields @GMTDA and @GMTDY. These global fields are
  set by taking global field @U1ZID (GMT last midnight value) and
  applying the GMT difference to get local time last midnight.
  This value is a calculated local last midnight. The calculated
  local last midnight is compared to global field @U1MID (actual
  local last midnight). The GMT date is set based on whether the
  calculated last midnight is equal to or greater than the value
  in @U1MID.
  
  APAR PJ40381 changed how global field @U1ZID (GMT last
  midnight) is handled when daylight savings time is active.
  @U1ZID is now relative to @C0CLO (perpetual minutes clock).
  When daylight savings time is active, the GMT offset and the
  daylight savings time offset must be applied in order to
  compare @U1ZID to @U1MID. Currently, program CDTC does not take
  the daylight savings time offset into account when it
  calculates local last midnight from @U1ZID. As a result, the
  GMT day is being set incorrectly in @GMTDA and @GMTDY.
  

Problem conclusion

• SOLUTION:
  First, program GLGL and macro gclkx have been updated. Every
  minute program CTDF calls GLBL (using CROSC GLBAC) to copy time
  fields from keypoint B to globals. GLBL has been updated to
  copy CK9ZID to @U1ZID. Also, macro gclkx copies the time
  related global fields from the main I-stream to all other
  I-streams. Now, macro gclkx will also copy @U1ZID.
  
  Second, program CDTC has been updated. When the GMT date is
  being determined, the daylight savings time offset is applied.
  Program CDTC gets the contents of @U1ZID (GMT last midnight
  value) and applies the GMT offset and applies the DST offset if
  daylight savings time is active. This result is compared to
  @U1MID (local last midnight value) to determine the GMT date.
  
  COREQS: NO
  None.
  
  MIGRATION CONSIDERATIONS: NO
  None.
  
  BUILD COMMANDS AND INSTRUCTIONS: YES
  #maketpf commands for linux
  maketpf -f CDTC cdtc.o
  maketpf -f GLBL glbl.o
  maketpf CDTC link TPF_VERIFY_LINK_REFS=NO
  maketpf GLBL link TPF_VERIFY_LINK_REFS=NO
  maketpf CDTC link
  maketpf GLBL link
  
  UPDATED INFORMATION UNITS: NO
  None.
  
  See your IBM representative if you need additional information.
  
  DOWNLOAD INSTRUCTIONS:
  http://www.ibm.com/software/htp/tpf/maint/maintztpf.html
  
  APAR URL:
  http://www.ibm.com/software/htp/tpf/ztpfmaint/put/PJ41068.htm
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  Z/TPF

• Fixed component ID

  5748T1501

Applicable component levels

• R110 PSY

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